How do I determine if adding an air conditioner will overload a circuit? I'm going to take advantage of some Memorial Day sales and pull the trigger on a portable AC unit for my "basement-ish" (bottom of windowsill is mid chest, rather than head height) apartment.  Before I do this, however, I've been researching online, and I want to make sure that I don't buy something that's going to overload the electric circuit it'll be connected to.

For the bedroom, the breaker indicates 15 Amps.  The circuit will additionally have a desktop computer, two LCD displays, and a couple of lights.  How can I tell if a new AC unit plus the existing items is going to cause tripped breakers or worse?

The only way to know what load a device draws is to put the device in to service and measure the load. The rating on the back is interesting, but many factors affect actual loads. An easy way to measure real loads is with a Kill-A-Watt.

Expect breakers to trip at 80% of rating, under continuous load. So 12A in your case.


My breaker panel is in a sump closet, should I move it? I just purchased a new home and I'm going to replace the breaker panel (it's full and I want expansion room).  The panel is located directly above the sump pump in a small closet in the corner of the basement.  I was wondering if I should have it moved when it's replaced?  The one electrician I talked to (my realtor is a former electrician and also my Uncle) said it's not hurting anything.

First off -- if the sump/sump pump protrude above the surrounding floor level, then they are a 110.26(E)(1)(a) violation:

  (a) Dedicated Electrical Space. The space equal to the width and depth of
  the equipment and extending from the floor to a height of 1.8 m (6 ft) above
  the equipment or to the structural ceiling, whichever is lower, shall be
  dedicated to the electrical installation. No piping, ducts, leak protection
  apparatus, or other equipment foreign to the electrical installation shall be
  located in this zone.

Second -- even if the sump doesn't violate the letter of 110.26(E)(1)(a), it could still be seen as a violation of 110.26, as it poses a potential tripping or wet-surface hazard to someone working on the equipment:

  110.26 Spaces About Electrical Equipment. Access and working space shall
  be provided and maintained about all electrical equipment to permit ready and
  safe operation and maintenance of such equipment.

So, I'd move the panel if feasible; at the very least, I'd talk to the AHJ about it -- I'd want to have an official interpretation on file for such a situation, even if the panel can't move.

Also, will the closet itself let the panel door open the full 90deg, and is there a space in front of the panel above the floor at least 30" wide and 36" deep? If either of those things are false, then the panel must move anyway, as the NEC working clearance rules in 110.26(A) would then be violated.


How do you remove the handles on this faucet I'm trying to repair a leak in both faucets in this sink.

I think the first step is to remove the faucet but can't figure out how to do this.

I can't see a set screw. I tried gently prying with a screwdriver. I tried unscrewing the skirt by hand. I tried unscrewing the handle parts. These appear to be caulked on. There is no brand name visible.

I don't want to use too much force if doing it the wrong way.

Do I have to remove by undoing the nut on the supply line? There isn't a lot of room to access these nuts so not sure what tool to use, which is why I haven't attempted this. The whole thing looks fairly old since the supply line is a solid metal tube, not flexible.

Any ideas on how to remove these faucets?

Thank you Kris -- it was possible to unscrew the base. I ended up using a basin wrench to loosen the locking nut underneath the sink a tiny bit and then that made it really easy to loosen the faucet by hand.


Honeywell water heater gas control valve pilot won't stay lit I have a State Industries GS650YBRT 300 water heater with the Honeywell electronic gas control valve.

This hot water heater will not light.

I am able to get the pilot light to light and after a short delay, the indicator light on the control valve LED status light begins to flash normally.

At this point, the pilot button should be able to be released and the pilot light remains lit in order to select an operating temperature on the control knob.  However, as soon as the pilot button is released, the pilot light extinguishes, regardless of how long it is held in after the pilot light initially ignites.

Obviously the system is sensing the pilot light being lit in order to cause the control valve LED status light to flash.  The status light flashes once every 3 or 4 seconds and does not indicate any faults, so why will the pilot light not remain lit?

The device probably has more than one pilot light sensor...for safety.  The electronic one is saying OK, but a physical backup sensor may not be detecting the pilot flame.

If there is a small rod in the path of the pilot flame (the physical sensor), you might try cleaning it with a bit of emery cloth or steel wool.


Why are light fixture wires allowed to be lighter gauge than house wiring on the same circuit? why do cables joining the wall sockets in a house need to be thicker than the cables joining the light fittings? I don't understand and I need to know before I buy it.

The wires to the light fixture will only carry the current drawn by that particular light fixture (on the order of 1A or less, for simple fixtures). The wires in the wall between fixtures carry current for all fixtures on the circuit, and are protected by a fuse or circuit breaker in the main panel. The wires in the wall must thus be sized to carry the maximum current allowed by that circuit breaker. For 15A circuits, this is #14 wire; for 20A circuits, it is #12 wire.

Note that the wires to the fixture must also be sized to carry the maximum expected current, but that is (largely) determined by the manufacturer of the fixture. Light fixtures have a sticker somewhere stating the maximum wattage of bulb that can be installed. This is partially due to heat (not really a concern anymore with CFL and LED bulbs) and partially due to the size of the wiring.

Some (better quality) fixtures / equipment will also have internal fuses or breakers that are sized to protect the wiring in the cord.


Electrical wiring under deck If I run electrical wiring under a deck, what conduit and strap material / grading do I need? It doesn't have to be the underground / metal materials, right?

I like to build something similar to this

I found it on this website:

http://www.thedeanfamily.com/deck_5_.htm

Yes, PVC conduit is nice stuff.  Make sure to keep water from entering it, or it may carry water to places you don't want water. (that said, all outdoor conduit is presumed to be 100% full of water all the time, so you must use wet-rated wire).

You'll be using single wires in conduit, just like most commercial buildings.  You need wire marked for wet locations.  There are many grades of wire, but what I find on store shelves is THHN or THWN - the latter has the "W" wet rating.  The cost difference is so small that many places only stock THWN -- but check, don't take any THHN.

You can choose solid or stranded wire, stranded is a lot easier to work with, but sometimes more difficult to terminate.

You cannot shuck down Romex wire and use the white and black wires, because the interior wires are not labeled.  Shucking down to bare wire for bare grounds is fine.

You will need at least 3 rolls of wire.  It's most economical in 500ft rolls.

Green or bare for ground wires (if you use them)
White or gray wire for neutral (I recommend white, you can use gray to distinguish a neutral from a different circuit.)
Any color not mentioned above, for your hots.  Most people go black, but you are welcome to install a rainbow of colors if you like, the only rule is you must be reasonably consistent within your installation.  So if you use orange for switched-hot for lighting, stick with that.

You will need to run a ground wire with plastic conduit.  I recommend you run a ground wire with metal conduit - in the great outdoors, that stuff will rust, even if it's galvanized, which will eventually cause grounding problems.

If you have metal (commonly aluminum) boxes in your system, there will be a hole already tapped 10-32 for a ground screw.  Attach a pigtail of solid wire to that screw, and wire-nut it to your other grounds.  I use stranded wire myself, and a crimp-on ring terminal.

In your photo, that guy needs more support for some of those pipes, especially the long run on the left.   PVC needs support at closer spacing than steel EMT.

Don't even think about buying PVC at the big-box store or any national-chain seller, because they won't have all the parts.  They'll have brand X boxes and brand Y box covers, and no, they don't play well together.  BTDT.   Rather than have to go to the electrical supply house 3 towns over for the missing bits, create a relationship with the electrical supply house in your town and use the system they sell and fully stock. For one thing, it'll be cheaper - big-box creates the illusion of cheap, but nails you on all but the most mainstream.


What kinds of items should not be put into a sink waste dispenser? With some of the advanced food waste dispensers available today claiming to grind "anything" and do so quietly, it may be tempting to skip regular waste disposal, especially if taking the garbage out is not the most pleasant of chores.

While common sense dictates that bottles, cans or utensils (I didn't make the last one up) should not end up in a sink waste dispenser, what innocent-looking items should not end up there either?

From the operation manual of the most expensive Insinkerator:

  This product is designed to dispose of normal household food waste; inserting
  materials other than food waste into disposer could cause personal
  injury and/or property damage.

Not a surprising disclaimer.

  Do not put the following into a disposer: clam or oyster shells, caustic
  drain cleaners or similar products, glass, china, or plastic, metal (such
  as bottle caps, steel shot, tin cans, or utensils), hot grease or other
  hot liquids.

Why no hot grease though?

  Do not dispose of the following in the disposer: paints, solvents, household
  cleaners and chemicals, automotive fluids, plastic wrap.


Is a tilted drywall joint at an angled roof intersection to be expected? We have an older house and looking to sell it. We have a contractor in to add a small closet to my son’s room since we didn’t have one in there.

The problem is that the joint between the wall and slanted wall is crooked. When I asked the contractor about this he replied the following:

  I tried to put the closet in as square, plumb and level as I could. I had to shorten the right inside of the closet to compensate for the out of level roof and reduce that angle as much as I could to keep the new walls plumb and doors operating correctly. I don’t think we can adjust any further without negatively affecting more crucial lines and door operation.

Is this a valid point? I’m out of my element here.

I'm assuming the drywall at the top was not installed by the contractor, and he simply added the new drywall against it.  In this case his point is definitely valid, old drywall is going to be tough to butt up against, especially a slanted ceiling.  I'd just paint this and move on with life.  There is nothing structurally wrong done here, and I highly doubt anyone is going to notice, much less make a purchasing decision based on this!


"Plunge" VS "slide" using my sliding miter saw? I have a 7 1/4" sliding miter saw. It has the Diablo 60T blade.

Cross-cutting, I found out that it cuts "easier" when sliding the blade through the wood (like a handheld circular saw), than plunging/dropping the blade onto the wood (like in a non-sliding miter saw).

My question is, is this all in my head? Shouldn't it cut the same, since the blade is a circle and the same at any angle?

No, you're not crazy. The key is to consider how many of the blade's teeth are in contact with the workpiece at a given moment. The more teeth, the more resistance because you're essentially forcing each tooth into the material with your own muscle. Pulling will usually result in less resistance for the blade because it's cutting an effectively thinner depth at any point.

That said, it's not always best to do a pull or push cut. Some reasons to do plunge cuts:

You're trying to precisely orient the blade to a mark or other point in the center of the workpiece
You're attempting to minimize tearout on one face or another
You're making an incomplete cut

Also, there's possibly more risk of "blade walking" with a pull cut. Your arm is less prepared to resist motion if the blade does grab when you're already pulling toward yourself. I've witnessed some pretty hairy situations with very large radial arm saws walking into heavy boards. A 16" industrial blade doesn't like to stop suddenly with all its rotational inertia at play.

Push cuts are often inappropriate for trim work because they result in the blade tearing out upward, though what's usually the finished face of the workpiece.


What should I consider when buying a USB inspection camera? I have a slow leak in a stud wall; I know it is coming from 1 of 3 pipes.   I can replace any of the pipes without breaking into the wall; however I need a way to find out which pipe is leaking.   I can access the wall from the loft, or under the shower tray.     There are no cross timbers in the area of interest, so access is easy.

I feel that an inspection camera would help, as I own a laptop I see no point in paying for a screen so am thinking of a USB based camera.

You might call the local rental center and ask if they have something.  If you just need it once why buy?  An inspection camera is nice, but you might also be able to see what you need with a mirror.

Another idea might be to slide pipe insulation or split tubing over the pipes.  This can trap the leak and guide it to where you can see it.


How thick should the seam coat of thinset be for Hardiebacker boards in a tiled flooring application? I recently taped my Hardiebacker boards with alkalai resistant tape and applied some thinset mortar over it. However, I'm a bit concerned that I laid it too thick. If I put a 12" x 24" tile over one of the seams, it definitely rocks back and forth a bit. I know that large format tiles like that will typically rest on a thicker bed of mortar, so it should account for any of the seams, but i'm concerned about it nonetheless.

The mortar is feathered out to about 6" on either side of the joint. It's not as smooth as I had hoped and I'm also worried it will make getting a good, even comb hard to do. Should I take the time to smooth out the joints with a stone before tiling?

I think you will be fine.  As you pointed out, the thinset under the tile will offset any uneven bump in your subfloor.  An even comb of thinset isnt required.  whenever you press down the tile and level it, the thinset will move under the tile to compensate for any bump.

Usually i only put just a little between the hardiboards just to fill the gaps.  Having a perfectly flat subfloor is not necessary.


Is it OK to install a TV mount when it can't be attached to a stud at all mount points? I have a TV wall panel that can only reach two studs. I was wondering if it's fine to screw the left side and the center on studs, and have the right side anchored in the drywall.

My TV is 30lbs with the mount.

Also, the TV would be mounted a bit on the right of the TV mount. Does it matter if the weight is not 100% centered?

If you are concerned about the weight an easy solution is to put a sheet of plywood (or nicer wood, if it will still be visible once the TV is in place) across 3 studs.  Secure it with 2 screws into each stud.  Then screw the wall mount into the wood.

Doing it this way will definitely support the weight of any TV you might try to mount.  And allows you to mount the TV exactly where you want it without worrying about where the studs are.

You can paint over the wood to make it blend in with the wall but in most cases it ends up nicely hidden by the TV anyways.


How do I tile across two different wall materials? I would like to install a continuous pattern of tiles from floor to ceiling on a wall that is a combination of plywood (mounted to 2x4 studs) and a short concrete stem wall.

Is there a suitable backing/decoupling material I can install so I can tile continuously from floor to ceiling without an expansion gap, or do I need to change the wall tile design?

Easy peasy. Looks like there is a slight depth difference from concrete to plywood—not a problem.

Encapsulate existing plywood with 1/4” Hardibacker or other cementitious backboard using 2 1/4” galvanized roofing nails at all designated points. At the seam with the concrete, use fiberglass backer board tape and the same Thinset you use to set the tiles. You can set the new tile directly to the existing concrete as long as it’s smooth. If not, a skimcoat of Thinset mortar will even it out. If the difference is greater than 1/4” use 1/2” Hardibacker.

Use 1/4” Hardibacker and cover the plywood only. You have several options for the concrete. You could set stone tile or river rocks; many options. Since you want to go floor-to-ceiling with the new tile, for visual interest set a larger, thicker tile on the concrete as a “baseboard.” This base tile should be approximately 1/2” thick lug-back tile (or stone, etc.) which will meet the bottom edge of the hardibacker a quarter of an inch out. For wall tile, easiest installation is 1/4” thick, talc-back tiles.

If you post a photo of a design you’ve seen and want to use as inspiration, I’ll give directions on that particular installation process. Here’s an example of a tiled wall with a base different from the rest of the wall.

Post photos after your project is completed. Good luck!


Electric motor for opening gate? Our gate looks like this. It opens to the outside.

So I'm looking for an electric motor that I can install to open it by remote. But I have no idea where they're sold.

This gate used to have a motor on the top that would push the two gates and pull them back to close. If I remember correctly, the motor had two "arms" that would connect to each side.

But I've been searching the web and haven't found the appropriate motor.

Any help is appreciated.

NOTE: I cannot add motors on the side. My car won't fit if I put them there and my building doesn't permit it.

Not really sure why you’re having trouble finding a source. They’re called electric gate openers and if you have electricity already going to your gate, they’re easy to install. In remote locations, you can get solar powered ones.


How do I stain pine without streaks or blotches? I did some test staining on pine scraps, and I ended up with a cross grain arc that's darker than everything else. Where did I go wrong? (Or is it just the pine?)

(Related to this question, as a follow-up. I realized I had already accepted an answer to the original, so this should be a separate question.)

I recently built a pine bench, and I'm trying to figure out the best way to stain it. My wife and I decided on Minwax Hickory Gel Stain because we wanted a darker finish. The Home Depot paint/stain department employee also recommended it along with Minwax Wood Conditioner for staining pine.

I applied the Minwax Wood Conditioner (oil-based) to a scrap 1x12, and then 15 minutes later I applied the Minwax Hickory Gel Stain (also oil-based) with a foam brush and wiped it off with a rag 5 minutes later. I noticed there was an arc of darker color going against the grain on the test scrap. Any ideas how this happened?

I made very sure that I sanded with the grain (by hand), starting with 100 grit, moving to 150, and finally 220. The only thing that I can think of is I wiped the sawdust away with a very slightly damp rag, without paying attention to grain direction. Then about 15 minutes later I applied the wood conditioner. Could the be the cause of the streaking? I'd like to figure out the cause before I move onto staining my actual project.

Also, I applied a second coat of stain 8 hours after the first. I let it sit for about twice as long before I wiped it off this time. I didn't notice much of a difference in color from the first coat. Is there something about gel stains that it doesn't matter number of coats/how long it's left on?

EDIT: Here's a photo (the streak starts in the bottom left and goes toward the top right):

The random little spots running in a line vertically are test distressing marks I applied, to see how they would turn out when stained.

I prefer to use a thin, almost watery, stain applied with a cloth. Two or three coats, with a light sanding between coats gives a good finish. Maybe it's just the way I apply it but I can't get thick stain to go on as evenly as I'd like. I also haven't found any huge difference between similar products form any of the leading brands, so I don't have any preferences n that score.


My ceiling fan is sparking even though i have turned its switch off. What to do? Will it cause a fire? I was sitting in my room when I noticed that the ceiling fan was sparking and causing fumes. I tried turning it off but neither it stopped spining nor sparking. I'm really worried about whether it will cause a fire or something. It stopped only upon switching off the main supply. Pls help me asap.

With a lot of new ceiling fans, the "switch" in the box in the wall is nothing more than a wireless transmitter and the fan is permanently wired at the ceiling through the wireless receiver. So if that receiver unit fails shorted, the fan cannot be turned off. If you are not comfortable with electrical work, this is something that will require the services of a qualified electrician.


air conditioner pipe pvc glue I recently bought a new air condition. The guy who came to install it in my bedroom used PVC glue to joint two pipes the one of the air condition with the outside one(instead he could use something else), ..and this pipe get the air inside and water outside.
The first 24 hours there was a toxic smell of the glue even if it was off. I had the windows opened for hours and after I closed them , you could smell again the glue. Now(after a week) you can't smell anything except if you are under the air condition which it has a strange smell (maybe it is the air, when you turn it on), I can't understand if it smells glue or because the air condition is new.
Is now the air condition good for use?
I am worried if the smell is still in the pipe.

Keep the fan on for a week and all the solvents in the glue should out gass in this time, most water pipes are glued and charged with water within 24 hours and in a day or 2 the solvents are gone and don't show up in testing, have been through this several times. A total pain in my back side. After 36 hours the levels were not dectable on a MSA or RGA that the owner who insisted on CPVC when I suggested copper. I think his total bill on the 2 samples for each test was several hundred each + the cost of a technician taking the samples... Give it a day or 2 with the fan on and I believe you will find the same.


Does code prohibit using salvaged materials in new electrical work? Does code prohibit using salvaged materials in new electrical work?  Can wire, receptacles, switches, wirenuts, boxes, connectors, etc... be reused?

As long as the components meet current code they can be reused. For example if I replace all the switches and outlets in a home and the outlets are 3 prong and in good shape I will save them and the switches for small repair jobs. You would think after 35 years of doing this I would have truck loads but I only save the quality parts; backstab only devices usually go in the trash and I use enough for friends etc that I only have a medium box full.

Wire can also be reused but I usually will not save romex under 10 awg and then if only in like new shape. I will regularly save larger thhn/thwn wire and inspect it prior to reusing.

Even breaker panels can be reused if they meet current code but in many cases I save the older quality panels for subs in a pump house or garage because most of the time they are only 60 to 125 amp. With all the new AFCI and GFCI requirements I prefer getting larger panels for a home.


Should I have my old ceiling vacuumed before installing insulation? My house (built about 1890) has no insulation in the roof and so I plan to put in insulating batts.  There is a lot of old dust and a few possum droppings up there, and I have heard that the dust can contain lead from the leaded-petrol days.  Should I get someone out with one of those big roof vacuums to clean it up before adding the batts?

You can get simple lead test kits at your local hardware or box store. Check the "dust" for lead. If you don't feel comfortable testing it yourself, hire a pro to do it.  Try not to disturb the dust until it is determined to be lead free. Lead is only bad for you when airborne, so keep it in place, don't disturb it. Wear a dust mask or respirator to be safe.  If it is lead contaminated, do not use a vacuum to collect it. You will need to contract a lead remediator to do this with specialized equipment. Do NOT attempt to do this yourself or hire a non licenced person to remove it.  If there is no lead, you can remove the droppings and dust with a shop vac or hire it done.  Any no-lead dust is not big deal, but I would be inclined to remove any rodent droppings before installing your insulation.


How can I reduce flex/sway in my pergola? I'm starting my backyard renovation project.  I've put in a large concrete slab (18'x26').  Now I'm building a Pergola over the slab.
My pergola construction is as follows:
6  - 6x6x10 posts (Grade 1)
12 - 2x12x20 beams (Grade 1)
Posts are held to slab using Simpson Bases anchored into slab
Beams are held to posts using notches and double through-bolted on each post
Rafters are 2x8x16 that overlap each other 24" and are through-bolted diagonally at the seams.
The posts,beams, and rafters are built level (no slope)
Above the rafters I have some 2x4x8 runners (sloped)
Above the 2x4x8 I plan to add 2x2 runners
This is my basic construction.  I'm experiencing a little flex/sway in the structure but I'm not finished tying it all together yet.  I'm using Simpson H2.5 Hurricane straps placed diagonally on every intersecting rafter/beam/runner.
Will adding all of the hurricane straps help tie it all together, or, should I consider some cable tensioning "X" braces on my structure?  I was thinking of adding (2) "X" braces if it doesn't stabilize after I'm done adding all my Hurricane ties.
Anyways, any advice (good or bad) you can offer is highly appreciated.  This is my first pergola project and I'm not an engineer/carpenter.  I'm trying to do it as right as I can realistically do within my budget and skillset, so, be gentle.  :-)
Notes:
The 2x12 Beams Span 13' Between the posts
The 2x8 Rafters Span 11' Between the posts
The 2x8 Rafters are spaced 18 inches on center
The 2x4 Runners are spaced 16 inches on center
The 2x2 Runners will be spaced 12 inches on center

Triangles are stable, squares are not.
Finish the knee braces.
You might be able to make them more simply by making them from narrower material that will fit between the beam members as they are (ie, they don't need to be the same width as the post, so they can be the same width as the cut-down section of the post the beam is wrapped around.)
Depending on height and why you have double posts on one side, you could also X brace on that side between the double posts.


What is this panel in basement wall of 1940s house? When I removed a cabinet from our basement wall today I discovered the panel in the photo below. The panel is metal, approximately 2 ft wide and 1 ft high. It has five   1.5 inch holes in it, each one covered in mesh (see close up). Behind the mesh I can see gravel. This plate is located in the basement wall directly below the front door. The plate is approximately 4 ft from the basement floor, and 2 ft below ground level (i.e 2 ft below the front door). The house has a cinder block foundation (but there is no cinder block behind the panel). The house was built in 1949. There are no utilities entering the house near the panel.  Any ideas what it could be for? Many thanks!

Would this be in an area that snows or could get cold. It's not a coal chute as most of those were not under the front door. My thinking is this - Warmer air from the cellar escapes and keeps the area in front of the door free from ice and snow -hence the gravel which probably extends down the outside wall. Its a simple convection heat source and very energy efficient.


Can I put tile in my basement over Ditra and existing mastic? My basement has been prone to getting water for many years before I bought the house.  We're having the basement walls repaired (excavated outside) & sealed.  So this problem should go away.

The basement floor currently has linoleum tiles that are all coming up from the years of constant water damage. Beneath them is what looks like a black mastic.  Its hardened to the touch in most areas (there are a few sticky sections).

I understand it might have asbestos in it.  We had an asbestos inspection done recently and they tested the tiles (report says 0% asbestos) but it is unclear if they tested the mastic.  The room is over 1100sqft so it would be alot of work to get it all off the floor and the possibility of asbestos being in it makes removal that much less appealing.

I've read mixed things on the internet about thinset over mastic.  I was thinking about laying Ditra over the mastic to accomplish a few things:

I can lock the asbestos down, safe beneath the floor
I dont have to kill myself trying to remove it
Acting as a waterproofing material

My concern is thinset not bonding well to the mastic covered floor.  I've read that if I use a high quality thinset, I should be able to secure the Ditra to the mastic pretty well.  I'm considering using Laticrete 254  Platinum.

I also wonder if the mastic will hold moisture in the thinset and if so, if I should opt for an unmodified thinset instead (if both mastic and Ditra will be impervious to water).

Schluter may not warranty Ditra if your slab does not permit moisture and you use a modified thinset.

Laticrete Stratamat has a "mortar hydration vent" that is claimed to allow either modified or unmodified thinset.  I have found significant price breaks for Stratamat if ordered online.  Local suppliers are a bit higher, but sometimes worth spending extra for "I-gotta-have-it-now" moments.

I would do an experiment with a modified thinset and a couple of cheap tiles...  Test adhesion at 12 and 24 hrs..  Use the std. Rockford chisel-and-3-pound-maul shear test...(wear goggles).


Is the part pointed out by red arrow a stud? Consider the following image. Is the part pointed out by red arrow a stud? What is the blue part called?

The part pointed at by the blue arrow is a "doubled top plate".

In this case, the wall it's on top of is a load-bearing wall. You can tell because the inner ends of the ceiling joists rest on it. If you pulled that center wall out, there would be nothing to support the top plate and therefore nothing to support the overlapped, inner ends of the joists. Pulling that wall would end up causing collapse of the structure. Handy for demolition, not so much for a simple remodel.

It may well be load-bearing even if the joists run all the way from outer wall to outer wall - that would depend on the height of the joists. Are they tall enough (and therefore strong enough) to span the full width if that wall were removed? To make that determination, though, would require looking at the structural design of the building, and might require the services of a structural engineer for confirmation before removing that center wall.


voltage draw differences on GE Spectra electric range/oven My wife tells me not to use the clock timer on our GE Spectra 220v range/oven, but rather use the Microwave timer since it's 110v.  She contends that everything on the GE 220v range/oven no matter the clock, timer, range top coils, or the oven uses 220v to operate.  I told her logically it would seem that even though the wattage/volts is 220v that it steps up or down depending if you use the timer, or rather it may take less volts to heat soup on the 6" or 8" coils versus the oven to bake something.  I through out a computer term....dynamic allocation....for the voltage it would take to run less demanding options on the GE Spectra. If your set the timer it has to be a very low draw, so much so that you would have a hard time comparing that to using the timer function on a microwave that runs on 110v.

That would require way more smarts than the current mains electrical system has.  Mains electrical is a constant-voltage system (as opposed to a constant-current system like you find inside a fluorescent ballast).  Mains will be 240V at all times.

Most stoves work by either switching 240V on and off, or doing some wave-shaping tricks that chop off part of the 240V waveform.  At less than 50% chop, peak voltage will be somewhat less than 240V, but not less enough to be helpful for life safety.

Now, in America 240V is delivered as split-phase with a center-point called "neutral".  120V circuits are wired between a phase and neutral.  That means if you get between 240V and ground, you'd only get bit by 120V.  Most ovens use the neutral to allow clocks, electronic controls and the oven light to be 120V, meaning you can use common incandescent light bulbs instead of weird 240V bulbs that would be hard to find.

If she is complaining about being shocked, then perhaps she actually is being shocked.  There are two ways to wire an oven - a 4-wire connection which is as safe as any modern equipment, or a 3-wire connection which omits ground, and potentially catastrophically, connects neutral to the chassis of the oven. (WTH?) The idea is that the neutral wire is unlikely to fail on an installation that is rarely disturbed.

Well. The problem is that if the neutral wire does fail, then it most definitely electrifies the chassis of the oven.  The oven electronics may not flow enough current to electrocute someone, but the oven light definitely would.

So if the oven has a 3-wire connection, that is something to take very seriously. I would recommend retrofitting a single ground wire from the oven to the panel or intermediate location, and removing that pesky neutral-ground strap on the oven that connects neutral to ground.  Once the oven chassis is properly grounded, at that point she is just mistaken.


Why does my heat pump's fan always stay on when in heat mode? I have a heat pump. This unit does have emergency heat. I only know this because I have used it. I noticed that the other day the fan stays on with the heat on. The fan switch set to auto and the temp set way below the actual room temperature. I removed my thermostat to examine the wiring and it has E and W2 connected together. Could this be the reason for the fan constantly running?

The heating fan will run for a cool down after the heating elements are turned off. If you listed your Furnace Model and your thermostat model we could check the wiring for you and suggest what you need to do.

But yes it sounds like the Thermostat is wired incorrectly.


GFCI outlet tripping My son has 2 regular outlets the second leads to the first of 4 GFCI outlets in the kitchen. When he uses either regular outlet it trips the GFCI. We changed both outlets although there was no apparent defects or damage. It still trips the GFCI. We then changed the GFCI. Again it trips when either of the two regular outlets are used. He can use the GFCI (the one that trips) with no problems and the three after the one that trips are fine. Which makes me believe the problem lies before the GFCI outlets begin.  It drives me nuts when I can figure things out. Anyhow here's a list of the order of the outlets.

Regular - Regular - GFCI( the one that trips) - Switch for above sink light - GFCI - GFCI

How GFCI is wired below:

Left side one 3 whites
Right side 2 blacks
Bottom ground

GFCI outlet wiring drawing ,,,,,,,,,,,

I think Kenny above was right.

From your wire count, on the load side, it looks like one black and one white go off to the properly-working GFCI outlets (which as others have pointed out need not be GFCI since they are downstream of a GFCI) while the "regular" outlets are probably getting a white from the GFCI load side, and a black from somewhere else (line side of the GFCI probably unless someone has accidentally mixed two circuits here).

This should be pretty easy to sort out and clean up, you just have to figure out which cable is the line feed, which goes to to downline kitchen outlets, and which goes to the downline regular outlets.


can KY jelly be used in a pinch if no silicone plumbers lubricant is available? this is NO joke! The tub faucet is in pieces right now and wanted to have repaired before the man of the house returns from his daily labors. I've replaced before but used no lubricant. That may be why it needs repaired again after 5 years. Everything was put together right but the faucet handle is extremely tight. Referred to the good ole internet but that question has never come up! REALLY???

KY is water soluble, so would be pointless as a lubricant for plumbing fixtures. In a pinch, maybe petroleum jelly would work.


Can I use a single dimmer switch to control multiple lights? I want to setup a parallel circuit for 10 light fixtures.... Can I use 1 dimmer switch to control all 10 light fixtures all at the same time?  Is this possible to make?  Thanks in advance :)

A given switch has a specified limit on the total power it can control. Add up the total wattage of all the bulbs and if this is less than the limit for that dimmer, then it should work. Note that for LEDs you use the actual wattage not the equivalent wattage for an incandescent which gives the same illuminance (lumens).

Also the dimmer switch must be one which is designed to control LEDs. A dimmer switch from decades ago probably won't work. For years I used a 30 year old programmable dimmer which was approved for incandescent bulbs to control an LED by using one incandescent and one LED in the two bulb fixture.


Is running a portable air con unit on a highly loaded circuit going to be a problem? The electrical situation in our house is that almost all of the outlets are on the same circuit/breaker and when there is too much load the breaker will trip. We need a new cable run to part of the house to separate the outlets... It is warming and I decided to plug in the portable air conditioner. I am concerned that if there is too much load in the house the voltage supplied to the portable air con might be too low, which in particular I know motors don't like... In this situation could the voltage be low enough to cause problems or will it be ok until the electrical upgrades are done?

The breaker will trip before the voltage sags, but if you're tripping breakers with any regularity, you have bigger problems.

It's time to have a marking party and label each outlet/device for which breaker it is (give them names like Thor  Hulk  Ironman etc).  Get a Kill-a-Watt measure the actual amps of the appliance.  Then label that too.  Now you aren't flying blind.  Tell the family "no more than 16" or whatever.

You will find that almost all the load comes from a very few appliances.  Don't make coffee with the A/C on, or whatever.


How do I anchor an acrylic claw foot tub? I have been working on remodeling my bathroom.  As part of the renovations we have decided to replace our old tub with an acrylic claw foot tub.  The tub is extremely light weight.  I am assuming that it needs to be anchored some how so that there isn't constant strain on the plumbing for the drain.  I talked to the plumber who helped me move the plumbing when I first started the remodel, but he did not have any answers for me.  My floor is ceramic tile, and there is basement below the bathroom so I can get underneath the floor if needed.  What is the best way to anchor this tub?

Here are a couple of pictures of the tub:

And from underneath:

I believe you just set it on the floor and let the weight of the tub and connected drain pipes keep it from moving.

If you are really worried about it moving you could mount some sort of small block to the floor behind where each leg will sit.  It would not be attached to the blocks but with for of them the tub would not be able to move.  But that may not work well with your tile floor.


Raised bulge lines on ceiling Can someone please tell me what is going on in my house. Almost all he rooms are starting to form these raised bulges lines from wall to wall on the ceiling.  They are raised and don't move when pushed on. I'm at a loss.

12-14-19 update
So the raised lines on the ceiling only seem to be getting worse.  Protruding more than before.  Every ceiling on the first floor has them now. Second floor ceilings don't show any as far as I can tell.  Not sure what is causing it.  I had my roof replaced and some roof ventilation installed when we bought the house last year.  Only seems to be getting worse as time goes on.

This is normal, they are just the seams between the drywall panels. Even the best drywall installers can't make a perfectly level joint. But, a skilled installer will feather them so they are not noticeable under most circumstances.

Based on the shadow, your picture has oblique (low-angle) lighting, it will accentuate the seams. If you have a long wall, put a flashlight near the wall skimming the surface. You should be able to see the seams on your walls also.


Extremely long dryer vent line, non efficient dryer my house is older, and my Dryer vent line runs the length of my house, which is approximately 30 feet.  I am constantly sucking water out of my vent line.  My new dryer still takes forever to dry clothes...  I need help! any suggestions?

Your dryer manufacturer will have specifications for maximum vent line length, including max distances depending on type and size of vent and how many turns.

It is very important that you:
- use rigid rather than flexible line whenever possible
- minimize elbows and turns
- make it as short of a run as you can (never exceed manufacturer's max)

It is not unusual to have a 30' length, but it should be rigid pipe. Check out this chart.


Wall surface is too smooth after spackle I had a hole in some drywall that I repaired with spackle paste. I sanded it down so it is level with the existing drywall. The problem now is that the spackle is smoother than the surrounding drywall. How can I create the same texture in the spackle so that it looks seamless when I paint over it?

If the drywall has a substantial amount of texture, you'll find 'texture in a spray can' at your favorite big box store. Probably get the one that says, "orange peel" on the label. Like this: spray texture

If it's just a tiny bit of texture, use a thick nap paint roller and start putting coats on. You'll have some texture in no time.


If I buy only one tool between a tile cutter and a wet saw, which one should I buy? If I have to buy only one tool between a manual tile cutter and a wet saw, I wonder which one you would recommend.

I have never done tiling  before and this is my first DIY tile project for a small bathroom. The floor tiles I bought are 1 ft x 2 ft porcelain. I do not want to buy an expensive tool or multiple tools, since I do not think I would do another tiling project in the near future. When I check the prices of the two, they seem to be more or less same in around $100.

Thanks in advance,

I do not think I would do another tiling project in the near future.

It may be best to rent or borrow a wet saw; Buy one on eBay; or sell your new one on eBay afterwards as a used item.

(community wiki because an unanswered question with answers in  the comments is like a faraway tap dripping in the night.)


Can there be too many seams in a dryer vent pipe? BACKGROUND:

We have to vent our dryer outside and we will NOT be using
any form of flex pipe.
The whole thing will be vented with rigid
4" aluminum vent pipe.
It is going to take a total 18' of pipe and one 90 degree elbow in order to make it an exterior wall. We have chosen to go to a wall versus out the roof top since we don't want to mess with installing a vent box on the roof. It would also create unnecessary angles that we would rather avoid, and even though the exterior wall is further away, there is no elevation change, etc.
Including a diagram to show what I'm talking about...

QUESTION:
As long as I connect the pipe sections correctly (with the crimped ends pointing away from my flow source) does it matter how many seams I have? Problem is, I can only get ahold of 5' sections of pipe. No one seems to carry anything longer, even places like Ferguson, etc.

OTHER:

I am under the impression as long as I am under 25' I should be fine.
I am also assuming that the 90 degree elbow "counts" as 5', so my total run is around 23'.
Since the dryer was originally vented into this attic/crawl space about 30 years ago, anything is better than the current set up!

The number of seams is really not the issue.  The length is, but this is probably a better solution than alternatives.

When you put the pieces together, you should arrange that the downstream sections fit over the upstream, so the interior transition doesn't have an edge that lint catches on.

Another subtle thing, would be to try to put a slope down from the elbow to the exit, so any condensation runs out.  Avoid any dips.
I put aluminum tape on mine to seal the joints and keep it together.


Does this wall tile's mortar contain asbestos? I have some missing tiles behind my sink cabinet and had to clean up some pile of crumbled material from this mortar. This is an old house but the bathroom tiles could have been remodeled since the 1980s. Does it seem to contain asbestos? I just found out it was used in some mortar mixes prior to the 1980s.

There's really only one way to tell with a building that is old enough that it might be there (and it "might" be in many things, whether or not it was common in those things.)

That way is to take a sample and send it to a laboratory for analysis.

I once got curious and looked into what that involves, and it's essentially some fancy microscope work that does not look particularly likely to be easily replicated by the home scientist.


How to fix gaps between flooring planks in mid-1800s house? I live in a mid-1800s house, which I plan to sell this Spring. The original (I think) wood flooring has gaps between the planks, some pretty sizable (photos follow).

Is there any good fix for this? I've seen people use wood filler/epoxy, and it didn't seem to turn out well. Perhaps doing that and painting/dying it black might work better.

I've heard the "old" solution was to pack those spaces with rope, but I don't think that would look better than the status quo.

Any suggestions?

Photos, big gap:

Medium gap:

Small gap:

I think those gaps in the floor are part of the charm of old wood flooring. I definitely would not slosh epoxy all over them. I guess it partly depends on the style of the house and the type of buyer you're trying to attract. Original wood flooring may be attractive to some people if it's restored nicely.


What to do first in a basement? Dricore then frame on top? Or frame and then lay dricore? My thinking is to use blue wood with a plastic barrier underneath, and then lay dricore up to the finished walls.

However, the dricore instructions say that framing should be on top of the sub-floor.

This is a 2-y.o. basement with no signs of moisture yet.

Is the framing on top of dricore actually necessary?

The framing in a basement is non structural. The only weight on the walls is the wall itself and minor loads from shelving, etc.

The purpose of Dricore is to isolate everything from the floor and walls except the plastic spacing material on the bottom. Dricore is also installed with a small gap at the walls. If you build on top of the Dricore, the studs are kept away from any moisture that may seep through the basement floor or seep through the walls.

Keeping the studs from touching the basement walls also helps create a thermal break to assist with insulation. Additionally, an air-gap behind the insulation also increases the R value.

Build the walls on top of the Dricore. Pin the Dricore to the floor as directed.


How to seal where the wall meets the floor? My house was built in the 40's.  It is in upstate New York.  There is a draft in the bedrooms where the exterior wall meets the floor, which is hardwood.  I can think of several ways of sealing the draft.

Use transparent caulk where the baseboard meets the wall and where the baseboard meets the floor.
Temporarily remove the baseboard and do something more effective -- perhaps paint with something like mastic or flexseal (having first put down masking tape), or perhaps somehow install a strip of some sort of tape or barrier sheet to cover the line where the wall meets the floor.  Put the molding back.
We are thinking of getting rid of the hardwood floor and replacing it with laminate, because the floor is uneven and creaks and squeaks something crazy.  If we do this, maybe there is some special procedure to be done after removing the old floor and before putting in the new laminate.

There are several ways the air can reach the gap between the floor and wall.  Your best solution would be to find the entry point and seal it there.  Unfortunately, that's almost impossible so your next best answer is to seal the gap between the wall and floor.

Your first answer, caulking above & below the baseboard, is the least obtrusive but would be the least permanent.  As the wall and floor flex with changes in temperature, humidity, and load, the 2 seals could break loose.  The seal against the floor is also likely to be knocked loose with regular sweeping and foot traffic.  Although better than no seal, it's not my preferred approach.

I did similar to your second answer in the laundry room of my own 1929 home.  I removed the baseboard & trim, stuffed any gaps over 1/8" (2-3mm) with foam, then caulked over the foam and reinstalled the trim & baseboard.  It's amazing how much air leaks through such a small gap!  The water lines to my washer froze several times before I sealed the gap; the space hasn't dropped below 50F since I sealed it.

If you remove the hardwood to replace it, remove the trim as well and use the opportunity to seal any gaps where the wall meets the floor.  Walk around the floor inch by inch and screw down (not nail!) anyplace that moves or squeaks.  A simple web search will find more about eliminating floor squeaks.  Also look into a roll underlayment to go between the subfloor and new, floating, laminate.  This would isolate the laminate from the subfloor to eliminate another source of squeaks and cover gaps in the subfloor, reducing drafts from below.


Can I add concrete from the old posts in the holes for the new posts and pour fast setting concrete on top? I am about to install galvanized steel posts in fast setting concrete (QUickrete Fence n Post).
Someone suggested that in order to save money I could break up smaller pieces the old concrete bases (I will have to do that anyway so I can move them to the car to dispose them) and put some of these smaller pieces of concrete in the holes and pour fast setting cement in.

Would there be any problems with this move?

It would be appropriate to substitute your old concrete for the gravel at the bottom of the hole (assuming you broke it small enough...), but I wouldn't mess with the concrete mix itself.

Think about it: you'd be upending the factory mix by adding more 'gravel'. Manufacturers have thought about the mix more than we can imagine, so I'd defer to them.

While I get that hauling more bags of concrete and more waste is a pain (maybe dribble the waste concrete out in 5# increments in your household waste, if permitted), you might take comfort in amortizing your work over the life of the posts.


Can't make progress with a hammer drill into 60 year old concrete I have a Ramset Hammer drill with the Hammer drill option set, speed set at low [1], and a new 1/4" masonry/concrete bit. I can't get more than an 1/8" in about 15 minutes of incremental drilling with wax and cleaning.
I have tried other area's and in the foundation wall and got the same result.

The drill is in forward and in hammer mode, thank you -). The drill is not cordless, but I have had it for 30 years when I use to install Kawneer and Vistawall Curtain walls and skylights (commercially).

The bit still has the hammer flutes/blades and the are not chippedits new.

There isn’t any aggregate in the wall that’s what is odd, it’s like a solid slurry of Portland cement. - think plaster consistency, tough stuff in 3 of the four walls tested. The drill is in hammer mode the select switch mode is set and on setting 1, low speed to prevent over-heating of the bit.

I’ve drilled steel I-beams with this drill up to 1/2”, and modern concrete (90’s) with the same bit type, the drill it’s just like a Hilti, same bits will work. I got them from ‘Fasterns inc.’ [mobile construction delivery service]. Thanks for the feedback and thoughts, much appreciated.

Are you using it on the hammer drill setting? Some hammer drills allow you to turn it off and use it as a regular drill. Old concrete becomes very very hard and without the vibration of a hammer drill, you basically can''t get into it.


High EMF from electric wiring I'd recently been given an EMF meter and when I turned it on, the EMF around most of the house was around 15 head height. If I'm downstairs and raise it to the ceiling it's well above 100 and the same upstairs putting it towards the floor. Now this is a bit worrying as we've been living in this house for the last 16 years but not only that I've recently had kids and where my 3-year-old sleep's he's being pummelled with 20 gauss.

I'd turned all power off at the fuse and proceeded to remove fuses to narrow down which circuit was causing the high levels. My first thought was it must be the light circuit as it was the roof and floors that had the highest readings but it turns out it was the outlet circuit that's causing the issue.

I've done some research and found that a neutral wire returning via a different live wire can cause this to happen and is in fact quite a common issue.

So my question is where and how is it best to start to find where that neutral wire has gone astray?

I'm currently in the process of getting our old fuse box replaced with a newer version. So thought now would probably be a good time to look into getting this sorted. Thanks for your help in advance.

That's a big job.  I had to sort out a bunch of wiring in an old factory which had a lot of neutral problems.  I shut off service to the building and, at the panel,  "pulled off" one hot and neutral off each circuit and did a series of diagnostics, checking for resistance between it and the rest of the neutrals, and resistance between the hot and neutral, and hot and other neutrals - alternating whether night-lights were plugged in or not.  If anything seemed out of the ordinary I followed it to the next junction box and carefully troubleshot, and the next, and so on until it tested clean.  (this was a real mess as many circuits were MWBCs.)  I don't recommend this, but I also had a 120v extension cord coming from another building, and connected the pulled-off circuit to that, and sniffed for voltage being anywhere it should not.  I would not recommend doing that with 230v, that stuff bites hard.

It can help to install a GFCI breaker (UK: RCD) in your panel, as they will trip if there is any cross-neutral activity between circuits.  You can move it around from circuit to circuit. Likewise you can put GFCI outlets on any point in the branch circuit, which will protect everything downstream.  In fact, many service panels have an outlet right next to the panel, and you could install a GFCI in there, attach a hot and neutral wire to the "load" side, and use that to test each circuit in turn.  I wish I had thought of that in hindsight!


How do I stop weeds in desert landscaping? The primary culprit is actually grass.  Grass killer isn't an option because there are fruit trees involved.

My understanding is that a couple of inches of rock will stop them.  My wife disagrees.  Who is right?  Or does it need to be thicker?

(We currently have about 1" of rock the builder put down and it's clearly not enough.)

It might be a bit late, as the rock's already down ... but the easy method would've been to put down a layer of landscape fabric before you put down the inch of rock.

I have no idea how much rock would stop grass ... I'd think there'd be other factors in play (eg, what size of rock, amount of void space, how good the soil is underneath, etc.)

If you don't have much grass nearby, and you didn't do this in an attempt to kill off an existing lawn, the seeds likely came in with the fill soil; if you pull the grass as it comes up (before it goes to seed), you should be able to kill it off


Is corrosion on top to an otherwise working electric water heater dangerous? I moved into a house with an electric hot water heater.  The heater is old (11 years) but works just fine. However, the top of the tank has extensive corrosion, especially around the connections for the pressure relief valve and water in/out connections. I just flushed the tank, and there didn't appear to be any sediment (the water was at least visibly clear the whole whole time). I can't figure out how to check the anode rod, as I can't find a nut on the top of the tank (but maybe it is obscured by all the corrosion).

Do I need to worry about this, since everything is working? Or could the corrosion weaken the tank and cause it to explode?  Obviously, if the tank fails, I will replace it. But, I'm wondering if its condition is a safety hazard and I need to pre-emptively take care of it.

No matter what, it won't explode. Maybe a little bit of splat. But no boom. Ok, really, more of a squishing sound, the sound of your feet splashing through the puddle created when it fails. :)

There may well be an anode, connected to the input line. Or at least there was one, probably corroded away now.

Assuming a little water on the floor won't hurt anything, I would buy an inexpensive alarm that senses the presence of water on the floor. Its just a pair of contacts that set off a battery powered alarm when water bridges the gap. When it goes off, buy a new heater.

If some water in that area will be a problem, then the heater should be in a low pan that will catch a leak. If not, then consider a preemptive replacement, as this heater probably has only a few more years in it anyway.


How can I convert wall lights to under-shelf lighting? I have a home office, which currently has a couple of wall lights (controlled by switches on the wall, so part of the normal lighting circuit).

I'd like to install some wall-supported shelving, and the lights are in the way. I'd also quite like to have some lighting (possibly LED strips) under the lowest shelf to light the desk.

It seems to me that I should be able to just extend the wiring from the wall lights down the wall, and connect the under-desk lighting that way, so that it continues to be operated from the wall switches.

My question is: what's the correct way of going about this? I expect the light fittings will just have some wire coming out of the wall - should I install a backbox and some sort of front panel (with a socket, or just a fuse?) Should I angle-grind a channel in the wall and extend the wire, and if so how should I terminate it then? Or can I just chocbox the wire outside the wall and fill it in a bit?

Yes you can just extend wiring. However, exactly how will depend on the particular circumstances of your wall.

You can get plates that just have hole for the wire to come out of - this one from B&Q or this one, also from B&Q for example - so you could fit one of those. If the wire would get in the way then cutting a channel down to the correct height is the best bet. Make sure you use suitable conduit to protect the wire. You can then fit the plate at the lower level. You can use a blanking plate over the existing outlet, if you have enough depth you might be able to fit the plate flush with the wall.

I wouldn't chocbox outside the wall - that wouldn't pass code.

This might be one of those jobs that you have to get an electrician for - given the regulations.


Adding a return vent to a hot office I have an office with a significant amount of computer equipment in it that generates quite a bit of heat and is regularly 3-12 degrees warmer than the rest of the house when I'm working in there with the doors closed. (My house is a pretty large 5-bedroom house, so I'm not too worried about this affecting any large-scale balance.) Unfortunately, this room has no air intake vent. It does have a register from the HVAC. The room regulates its temperature fairly well with the doors open and I can feel a draft blowing out through the cracks in the doors when they're closed, so I think an air return is needed.

It's a squarish room with the HVAC register (4" x 10") under the window on the floor and the doors are on the opposite side of the room next to an air retrun vent in the hallway (it's quite close to the furnace and seems like a rather large cavity, not a long run so minimal friction). I've added a (bad) drawing of my office and what's on the outside walls. There is a basement below and a bedroom above this office, so neither the ceiling nor floor are really accessible.

Office Layout (the office is surrounded by black lines, the grey lines just show the outside rooms/areas, red show existing HVAC things):

Other than right around the door area, most of the walls are fairly off-limits due to what's on the other side (obviously not punching a hole into the garage, the bathroom is already too small, not making it smaller, and don't want to add anything to the foyer area for aesthetic reasons). I think the two areas that provide the most opportunity for adding an air return vent are either tapping directly into the air return cavity (shared with the hallway) or just opening up a new return pseudo-duct over the doors from the office to the hallway.

My concerns (I'm an engineer but no HVAC guy):

Because I largely want to remove heat year-round, I think the return vent should be on the wall near the ceiling (this is fortunate if I go over the door into the hall).
I'm concerned about noise transfer from the hall to the office or office to hall (I have a 3yr old, nuff said)
I'm not sure what HVAC codes & permits might be needed in this area of Indiana (Carmel). I think I might need a permit of some sort if I do HVAC duct work.
Something in my gut tells me I shouldn't tap into that air return cavity directly with the hallway having a large vent right there at the same spot on the other side of the cavity.
I understand this might not be 100% perfect with the heat generation in the office, but I'd like a large improvement and I think this will do it. Adding additional air conditioning into this room is likely too costly of a solution.

My questions:

Is there an obvious answer here? Is it bad to just vent the hot air into the hallway next to that air return vent out there?
If I go above the door, should I punch one hole in my office as high as possible with the second hole in the hallway as low as possible to maximize hot air going out while minimizing noise transfer?
How large should the holes be? If I go above the doors, should just 1 work or should I put 2 in, one over each door?
Should I use a "register booster" or other powered device to help push air through the return vent that I'm adding?
If I cut a hole into the existing cavity, how do I keep all of that drywall dust from going into my furnace (filter)? Or do I just do that and swap the filter out when I'm all done?
Is there something else I should be asking? I can definitely cut some holes into drywall but this is all new to me.

We’ve had several similar problems. We’ve solved them by 1) undercut the door, 2) through wall grille,3) through wall grille with sound baffles,

You’re right, you can’t “push” more air into the room without providing an air relief. (It’s the old straw example...you can’t blow into it if you have your finger over the other end. )

1) The simplest and quickest is to cut about 3/4” off the bottom of the door. We’ve done this several times and it works well, except you’ll loose a lot of your sound control. (The 3/4” will about the area of your grille.)

2) providing a through-the-wall grille above the door is also simple and you will also loose some sound control. This option has never turned out good for us. The grille is up near your ears so passerby’s can hear everything better.

3) We added a grille above a company’s presidents office door with sound baffles and it worked great. We cut the grille in just above the door header on the office side, then extended a duct with sound baffles up the stud space to a grille on the hall side near the ceiling.

The studs were 16” on center and we used the whole stud space. The duct was about 20” long and had 4 baffles. The baffles are made of strips of duct board mounted perpendicular in the stud space and about 4” apart alternating from side to side. This makes the air travel back and forth through the space. (We often use this design on large supply ducts to trap the sound of the motor noise coming on and going off on the supply side of heating/ac systems.)

It sounds like you have enough air when the doors are open...it’s just a problem when the doors are closed. (The straw example.) So, providing a “relief” vent seems like it will solve your problem. You’ll be “pushing” air out so it should not affect the house return air grille located close by.


Why do my pipes creak 10 minutes after using them? Our recently installed bathroom uses existing pipes that were previously plumbed into cut out sections of joists, with no cladding.

Approximately 10 minutes after use there is a quite loud creaking.

We were advised this was because of the absence of cladding, and that quick solution is to use expanding foam in between the pipe and timber joist, to act as cladding.  this avoids the much bigger job of completely refitting pipes and pulling up floor/re cutting joists.

The pipes are easily accessible at the moment as we are renovating (we have the ceiling off in the room below bathroom, but the bathroom itself is all tiled up).

Will this work, any other ideas?

I don't see why not.

The creaking is caused by the pipes rubbing on the joists as they expand and contract when first the pipe heats up as hot water runs through and then cools down as the water left in the pipe cools down.

If you wrap the pipes in insulation this will have the dual effect of stopping the creaking and keeping the hot water in the pipes warmer for longer.


Attach rim joist to post supporting roof I am going to build a small deck for a front porch to replace a concrete slab. The slab had a column that held up a post going to the roof above.

If I replace the slab with a deck, the corner post needs to go through the deck to support the roof overhang of the house above it. What are my options for accomplishing this? Should I have a post go all the way from a footer to the roof and then attach my deck to it somehow? What are the choices? Notching? What about making my footer come up high enough so that the rim joists of the deck can rest on it?  Another alternative might be to pour or build a column of concrete (with brick or stone on it) and then attach the deck to that somehow.

The picture shows the old column that I tore out. There is a temporary support in place now. The old column was hollow, made from 1x lumber. Should I go back with a solid 6x6 post?. That seems overkill, not to mention how heavy it would be to lift it up there.

Thanks for any and all ideas.

It is mostly a style and preference choice.  The original half inch lumber post is probably not structural, though it could well have been a cheap replacement for one which was more substantial.  From what I can see of the eves, a 4x4 or 6x6 post is appropriate.  Some jurisdictions require heavier columns beyond a certain length, usually about 10 feet.  Raising a 6x6 post is not that hard with a helper or two, or straightforward solo job with block and tackle attached to the temporary support.

A properly designed and built deck should have no trouble supporting a post.  You could build the deck with an equivalent support which is not in the way:  slanted support, temporary horizontal truss, etc.

If you like the look of a stone or concrete base, it should not rest on the deck.  Build it into the ground (depth as required for freezing conditions in your climate) and finish the column on top of it.  Build the deck around the column—it does not need to be tied together and it is probably better there be a small gap (1 inch?) to allow for independent settling.

You could also support the roof with a 45° to 60° post fastened to the side of the house.


Can I run a bathroom fan and a bathroom light off 14 amp twin and earth Can I run a 14 watt bathroom extractor and the bathroom light both of 14 amp twin and earth

Yes a fan is usually a very light load there is nothing wrong with them being on the same switch.

My jurisdiction requires the fan to run after the light is turned off (or motion ceases) for up to 15 minutes. But prior to this it was quite common to have them on the same switch.


How can I even out my subfloor? I bought a fixer-upper knowing little about how much of a headache I was creating for myself.

I've recently removed the hardwood flooring that was lain directly on the joists (no subfloor) of my second floor bedroom. I'm now laying a subfloor and will install hardwood flooring on top of it.

After screwed (yes - screwed) down most of my plywood, I noticed that my joists were uneven. As you go from one joist to another, they drop by as much as 1/2-3/4 of an inch. This is noticeable and I would like to correct it. Fortunately, I can easily unscrew my plywood (ha!)... but now what?

I'm leaning towards putting shims between the joists and the plywood subfloor, but I don't see much talk about doing that online. What kinds of shims should I put on the joists? Do they run along the joist or perpendicular to it?

Backtracking a little, the joists seem to be low because they were partially cut (I have no idea why) where they would otherwise rest on the bearing wall. I've put some blocking underneath them to provide some level of contact between them and the bearing wall, but I can't (and frankly don't really want to) raise them to be level. It has crossed my mind that I should replace them. Advice would be appreciated here, too.

It would be a straightforward process to shim all the low joists along their lengths. One would go about this by finding the highest joists and then shimming all the rest to be even with those highest joists. Of course this requires removing all of the existing subflooring.

It would require also that the highest joists be checked lengthwise to see if their top sides are straight. They may be high because they have bowed up during their aging. If they have bowed up then it would be necessary to adjust those joists first before tackling the lower joists.

There are multiple techniques to find the shim up amounts for each joist. Probably the easiest is to place long known straight members across the high joists at right angles. The bottom of the straight member represents the top edge of the shim that needs to be installed.

Another technique is to use a nylon string line stretched across the top of the joists and having its height adjusted so that it just skims the top of the highest joists. The string can be attached to vertical 1"x2" boards that are temporarily nailed or screwed to the face of the outermost joists across the room.

It would require multiple strings or straight members across the length span of the joists to get the reference level for each shim.

A really good way to make the shims is to acquire nice straight members such as 2"x4"s (or 2x6s) that are the same thickness as the joists themselves. One by one a 2x4 can be clamped to the side of a low joist with its top side adjusted to the string or cross reference straight member. Once carefully adjusted and clamped in place the 2x4 can be scribed with a line that follows the very top of the existing joist. A power saw is then used to rip the shim from the 2x4 to make the shim piece that attaches to the top of the joist. (Take extra care in cutting carefully and along the correct side of the line). The shims can be installed in place with construction adhesive and small finish nails or pneumatically shot brads.

The straight 2x4 material can be used to make two shims from the two straight edges. A more economical way is to use just one side of the 2x4 and then run the remaining piece through a table saw with the straight edge against the fence to restore the piece to two straight parallel edges to get it ready for the next shim marking.


Why can't I find a stud in this wall? I have problem locating my stud in my wall. I have tried many different ways to locate my stud but the results are weird.

Using Stud Finder:
The reading results are different everytime and weird. I get stud reading at higher location but than no reading right below. Please see attached image for the reading results
Using Magnet:
I use magnet to find the metal screws/nails but I found out all the screws/nails are 8in apart. Please see attached image I have mark all the screws I found mark with blue tape.
Knocking:
The entire wall sounds the same to me.
Electrical Outlets
I have two outlets on the wall. I open the cover but some how I can not tell if is attached to the stud or not and I use stud finder but I got not reading either from the left or right.

I was able to locate studs from other wall in my room but not this one.

I'm really appreciate if anyone can help me out on this weird wall.

The safest approach is to actually cut the wall open and see what you are really dealing with. While it involves drywall repair and paint, it also doesn't involve heavy fragile expensive items being hung based on conjecture. While the wall could be brick, it could also be studs (steel or wood) with resilient channel (somewhat age of building and local building practices dependent) - one of the features of resilient channel is better sound isolation, which is good for a party (common) wall. But some places a party wall is nearly always going to be 18" or more of masonry for fire purposes.

The wall shown here uses resilient channel, which is what I was looking for an image of, but also some other techniques that may well not apply.

You may find that you can "see" the resilient channel (or furring, as it may also be) better changing the studfinder direction (turn it 90 degrees, and sweep up and down)


How tight should threaded brass pipe fittings be? I'm working with 3/4" brass fittings, which seem pretty robust.

Some plumbing fittings should be only finger-tight. My friend said I should use 2 wrenches to make these as tight as I can, and then some.

How tight should I make them?

EDIT: I am plumbing water, but I'd like to learn to plumb gas, too.

As a general rule, fittings with tapered pipe threads (NPT) should not be assembled to a specific torque because the torque required for a reliable joint varies with thread quality, port and fitting materials, sealant used, and other factors. (Source: Parker Hannifin Catalog 4300 Port End Assembly, page T7)

Leakage path through NPT threads occurs between the very peaks of one thread and the very valley of the opposing thread. No matter how tight you make NPT threads, a leakage path still exists. It is the function of the sealant to block the path between the male and female thread.

This is most helpful!

Most screwed piping is tightened until it feels "right" and the fitting is pointing in the desired direction. What the experienced mechanic is often "feeling" is how the fitting is getting tight. Screw it into until it starts to seat. Then up the force a little by yanking. If each yank gives less movement, you probably have a sound joint. If the movement stops suddenly, you have probably bottomed out. The experienced plumber knows when to stop before he damages the fitting or boss. Caution is advised, tapered pipe fittings into an aluminum boss as excessive torque can crack the boss. This is especially true when using Teflon tape because the low friction of Teflon makes it easy to over-tighten.


Motion sensor with bypass switch? I wish to have a motion sensor on the lights in my garage, but I also want to have an override switch that works normally, and does not require a specific pattern to toggle the override in the sensor.

Is this circuit workable?

                / Wall switch
        +------0   0-----+
        |                |
--Phase-+-----Sensor-----+-------+
               |  |             Lights
--Neutral------+--+--------------+   |
--Earth------------------------------+

The lights are 4x flourescent tubes in two double fittings, but I may add more later.  Or may replace with LED fittings if that helps.

Essentially I'm trying to replicate the function of an Occupancy Sensor wall plate, like this:

For some reason these aren't available in New Zealand.  Voltage is 230 VAC at 50Hz.

The main reasons for concern are that:

the sensor will have live voltage on both sides even when the sensor is off.
the lights will not be isolated from power simply by turning off the wall switch.  Adequate labelling at the lights should cover this("WARNING DUAL SUPPLY!  Disable sensor AND check for voltage before servicing.")

Related to but not a dupe of

How should dual motion sensors be connected?
multiple motion detectors wired together

As I discuss in the answer you linked, that is fine.  There are some minor glitches in your drawing, but nothing worrisome.   Try

                / Wall switch
        +------0   0-----+
        |                |
--Phase-+-----Sensor-----+-------+
                 |              Lights
--Neutral--------+---------------+

(ground removed for clarity, actually it's needed at all devices assuming NZ code does not delete this popular requirement). And this is strictly a schematic, the wiring method must be such that currents balance in each cable or conduit.

A quality, modern motion sensor with its own neutral isn't going to have a problem with its LOAD hot being externally hottified by a switch or other motion sensor.

A maintainer, especially one who has looked around the room and observed motion sensors, should be shutting off power at the circuit breaker.  I have no sympathy for someone who wants to work the circuit "hot", unless NZ Code has a variation that says I should.  For all the servicer knows, it's wired with a switched neutral.


Water leaking from sprinkler system (by house) after opening up this spring I have my system winterized every year, when I started it back up this year, I noticed a pretty significant leak coming from under the circled black circular thing on top of the system (see picture attached).  This happened when I opened up the water valve in my house and then opened both valves outside.  I haven't noticed this in the past so I think this is the first time. I am not sure where to begin.  Each time I open up the right valve, which I believe is the one that allows water to go to the sprinklers, it leaks.  I have posted a picture and not sure what other info you need.  Any help you can provide would be greatly appreciated.  Thanks!!

That part is probably an anti-siphon valve, required by code for sprinkler systems. These have a one way valve which prevents back flow of water in the sprinkler piping from flowing back into the house in case of a pressure reduction in the house. Turn off the water to the sprinkler system and open up the unit and examine it.

Simple cleaning of the seal may restore functionality, but you can get rebuild kits for these anti-siphon/back-flow valves. I think it has a replaceable seal which may deteriorate.


How can I rewire half switched receptacles? In my bedroom the bottom half of all receptacles are controlled by one switch. Is it possible to have just one receptacle with top and bottom hot all the time?

The top half is hot all the time the bottom half is controlled by one switch.  Keep in mind there are six other receptacles in this room that are the same way controlled by the same switch. When I took the receptacle out the right side tab had been removed.  The top right screw had a black wire, the bottom right had a red wire, the top and bottom left screws had separate white wires.  I changed the receptacle out as suggested, I capped off the red wire and I capped off the white wire that was attached to the bottom left screw. I attached the other white wire to the top left screw and attached the black wire to the top right screw. I now have none of the receptacles working at all. What did I do wrong?

Yes. The tab between the upper and lower sections of each of these outlets have been broken off on the hot (black) side of the receptacles. There are separate wires running to the upper and lower sections. One is always hot and one is switched.

On the outlet you want always hot on both sections, first determine whether the upper or lower section is the switched section. After the power is turned off, disconnect the black wire on the switched part of the outlet. Cap that wire with a wirenut (and tape for backup). Disconnect the black wire from the always hot side of the receptacle. Make two short pigtails of black wire (about 3-4" each), strip both ends of these wires and attach one end of one of these wires to the upper screw and one end of the other wire to the lower screw on the hot side of the receptacle. Twist the other end of these pigtails together, along with the always hot black wire coming into the box.

This is effectively re-establishing the connection that was removed when the tab between the upper an lower sections was removed to make one half switched.

If there is only one white wire going to the receptacle, you don't need to do anything to that wire.  However, if there is a separate white wire going to the switched half of the outlet, the tab on that side may also be broken, and then you would need to treat it the same as the black.  That is, disconnect the switched white, cap it, create pigtails for the white side and attach them as you did with the black side.

Thanks to DoxyLover for pointing out the possible multiple circuit issue.

Supplement

As pointed out by @Johnny in a comment, an even easier solution is to replace the existing receptacle with a new receptacle that has intact tabs connecting the upper and lower sections (receptacles are very cheap) . Again, you would cap the wires connected to the switched half on the old receptacle, but then you only need to connect the black and white wires from the unswitched side to their respective screws on the new receptacle. The intact tabs will deliver power to both sockets on the receptacle.


Replaced pressure balancing unit in Kohler Rite-Temp temperature control, now valve body is leaking I have a Kohler Rite-Temp temperature control for my shower that was having trouble regulating hot and cold (it was either all hot or all cold). I took it apart and replaced the pressure balancing unit per the instructions that came with the replacement (roughly like here, but with replacement instead of cleaning: http://helptopics.us.kohler.com/link/portal/5641/5712/Article/2303/K-305-Rite-Temp-Valve-Cleaning).

The problem is that when I put everything back together, I noticed there was some water running out from under the controller when I turned the shower off. I took it apart again and ran it with the cover off. When I turn the dial to the off position, a large amount of water appears to be flowing from the valve body for about 15 seconds. In the picture below, the water appears to come out of the bottom where the little hole is as well as the two screws on either side.

Is this normal and I've just never noticed because the covers were on?

Have you checked to make sure the O-rings are seated properly? Also, I had better luck when I replaced the mixing cap and the PBU together. Kohler offers lifetime replacement on these parts, so if you can wait you can save some $$$.


Can I safely ground a light fixture if the ceiling box has two hot and one neutral wire (no ground wire) Checking for dupes, I saw this question, but the situation appears different as my box is metal, among other things.

I'm fairly new to electrical projects, so bear with me. I recently installed a new light fixture in a ceiling connection in a new building.

The fixture has black, white, and exposed ground wires, and came with instructions to:

Connect the black wire to the black wire
Connect the white wire to the white wire
Connect the ground wire to the green screw, and then to the ground wire.

So I checked that the power was live on a meter, then re-metered after cutting it to ensure it was safe, and proceeded to connect the wires as described, using the white, black, and brown wires in the ceiling.

When put the power back on, the light turned on.  But when I hit the light switch, I got a fireworks display and tripped the circuit.  After some research, it would seem that the "brown" wire that I assumed was the ground (by process of elimination) was more likely meant to be red (damn you, burnt sienna!), and was in fact a second "hot" wire, probably for a ceiling fan, or maybe a 240V device.  I'd connected the second "hot" wire to the exposed ground on the lamp, which was... not awesome.

So, I reconnected the black and white wires, and since there's no ground in the box, just connected the lamp ground to the green screw on the crossbar that's now screwed to the metal box.

I get that my worst initial mistake was not testing the voltage on each individual wire before connecting the fixture.  And I get to apply that next time, since I'm not dead.

But here's my question:  Is the lamp still grounded, given that it's screwed to a bar in a metal box, or does the lack of an actual ground wire in the box mean I can't ground it?

If I can't ground it, how concerned should I be when changing the bulb?

EDIT:  Some clarification points -

The building is very new.  I think it was completed in 2008
The box in the ceiling (more like a cylinder, really) is metal, but I don't know if it's connected to some kind of ground wire behind it, as it's attached to the ceiling and I didn't try to remove it.
There were three insulated wires in the cylinder: White, black, and brownish red
The black and red both were "hot" on a meter; the white was not

Sometimes when ceiling boxes are roughed in, they use x/3 with ground cable so that they can supply 1 switched hot, 1 neural, 1 hot/switched hot, and 1 ground to the ceiling box.

This allows a ceiling fan to be installed in such a way that the fan can be controlled either by a separate switch, or using only the attached pull chain. In this situation the red wire in the cable is usually disconnected and capped at both ends, and is only intended to be connected as needed.
You may be able to verify this by opening the switch box, and verifying the wiring at the switch. If this is the case and the extra hot wire is not needed, it should be disconnected and capped at both ends. Once that's complete, you can move on to determining if you have a proper grounding conductor.
Grounding Conductor
If the building was renovated/built in 2008, it's not likely the circuit does not include an ground conductor.  However, there are multiple ways to satisfy the grounding conductor requirement according to NEC 2008 250.118.

A copper, aluminium, or copper-clad aluminum conductor.
Rigid metal conduit.
Intermediate metal conduit.
Electrical metallic tubing.
Listed flexible metal conduit meeting specific conditions.
Listed liquidtight flexible metal conduit meeting specific conditions.
Flexible metallic tubing meeting specific conditioins.
Armor of Type AC cable as provided in 320.108.
The copper sheath of mineral-insulated, metal-sheathed cable.
Type MC cable where listed and identified for grounding in accordance with specific criteria.
Cable trays as permitted in 392.3 and 392.7.
Cablebus framework as permitted in 370.3.
Other listed electrically continuous metal raceways and listed auxiliary gutters.
Surface metal raceways listed for grounding.

Checking for a Grounding Conductor
The most accurate way to verify whether or not there a proper ground connected, would be to check for continuity between the junction box and the grounding electrode system.  In most situations this is not an option, so another test must be performed.
Checking Continuity to the Grounding Electrode System
To run this test you'll either have to be within reach of; or be able to run a lead to, the grounding bus in the main service panel.

Set your multimeter to the continuity setting or the lowest
resistance setting.
Place one lead on the grounding bus bar in the load center.
Place the other lead on the junction box under test.

If the meter beeps or gives a reading close to 0, the box and the load center are electrically connected.  This means there is a proper grounding conductor installed.  If the meter does not beep or has a reading of infinity, the box and the load center are not electrically connected.  You'll have to install an approved grounding conductor throughout this circuit, if you want proper grounding.
Checking Continuity to a Known Good Ground
If you have a known good ground nearby (from another circuit, for example), you can use this ground to test for an equipment ground at the box in question.

Set your multimeter to the continuity setting or the lowest
resistance setting.
Place one lead on the known good ground.
Place the other lead on the junction box under test.

If the meter beeps or gives a reading close to 0, the box and the known good ground are electrically connected.  This means there is a proper grounding conductor installed.  If the meter does not beep or has a reading of infinity, the box and the known good ground are not electrically connected.  You'll have to install an approved grounding conductor throughout this circuit, if you want proper grounding.
Check Continuity to the Grounded Conductor
If neither of these options are available, the next best option is to check for continuity between the box and the circuits grounded conductor (neutral).  These two conductors should be electrically connected (bonded) at the main service panel, so checking continuity between them can (usually) determine if there is an equipment ground.
WARNING: This method relies on the circuit being installed correctly. If the grounded conductor (neutral) is (incorrectly) connected to the grounding conductor anywhere along the circuit, this test may give invalid results.

Set your multimeter to the continuity setting or the lowest
resistance setting.
Place one lead on the grounded conductor (neutral).
Place the other lead on the junction box under test.

If the meter beeps or gives a reading close to 0, the box and the grounded conductor (neutral) are electrically connected.  This means there may be a proper grounding conductor installed.  If the meter does not beep or has a reading of infinity, the box and the grounded conductor (neutral) are not electrically connected.  You'll have to install an approved grounding conductor throughout this circuit, if you want proper grounding.
NOTE:
All continuity testing should be carried out while the circuit is dead. Shut off power to the circuit at the breaker before working on the circuit, and verify the circuit is off using a non-contact voltage tester.
Electricity is dangerous and can lead to property damage, injury, and death.  If you do not feel comfortable working with electricity, please contact a qualified Electrician.


Grounding subpanels located ~100ft from main breaker Based on this question on EGCs in conduit (in the context of branch circuits) and this question on conduit as a sole ground source, I would like to know whether two subpanels, located ~100ft from the main breaker panel, can be grounded to the main panel through the buried EMT connecting them.

This is how my system (kinda) looks:

I have two 100A subpanels fed from one 100A main breaker. Eventually, I plan to upgrade to 200A service and each subpanel will have its own 100A breaker (still in the main breaker panel).

This will mean two sets of hots and neutrals (four ungrounded conductors and two grounded conductors) with each panel receiving one set. I am trying to determine if I need to run a separate EGC for each subpanel (ex. two 8AWG Cu wires), a single EGC to both subpanels (ex. one 8AWG Cu wire, as intimated by the first linked question), or if the EMT connecting the main panel to the subpanels serves as an NEC-approved ground.

After calling my city's building inspectors, I was told the buried EMT can serve as the grounding conductor between a main breaker panel and a subpanel if the conduit also uses grounding strap fittings to bond the conduit directly to a busbar. The panel knockout to conduit/locknut physical contact is not sufficient.


Dryer exhaust from 2nd floor through crawl space, out roof This is my setup, 1986 built town home. I just purchased a dryer and before connecting it, I decided to inspect the 4" tube going from the dryer, up behind the wall to the crawl space / attic and out of a hole cut from the roof.

This is what I found:

That's just a 12" segment, I kept, it was like this for 12 feet. While I assume, total blockage is bad, I presume that so is even this amount of lint stuck to wall of the tube. (Is that right or did I remove it for nothing?)

Anyhow, they had a aluminum flex duct tube tube going through the wall, but I'm wondering if perhaps it would not be best to replace it with a rigid smooth (without the flex ducting) aluminum tube for the straight section that goes from the bottom the wall behind the dryer into the crawl space. Then at both ends, replace it with new, clean flex duct tubes.

I'm also thinking of adding a secondary lint filter so this doesn't happen again.

Any advice, or what to use is appreciated, I want the safest solution.

If possible, you want everything rigid: the connection from the dryer to the wall, the duct in the wall, and the duct in the attic. Sometimes rigid for the connection between the dryer and the wall is difficult to get right with a rigid duct so if you have to go with flexible duct then use the smallest piece practical.

A secondary lint trap is probably not worth the effort. instead, invest you money in a dryer vent cleaning kit, which is a brush with a couple of screw-together flexible rods that you can chuck in to a drill. Clean your duct using this brush once a year.


What are the specs for the Aprilaire 600 humidity sensor? The manufacturer replied to me that the humidity sensor used in their devices is "proprietary".  They didn't even answer my first question: "is the device based on capacitance or resistance?"

In this other stackexchange question I asked about how I might alter the circuit to deliver more humidity than the device does when turned to the maximum setting; the device reads 45% and turns off while my house only gets to 35%.  That question presumes a mechanism based on capacitance based sensor, and includes a circuit for how to "fool" the device into seeing a lower humidity than the sensor "sees".

In order to execute on this modification, though, the information I'm asking for in this question would be very helpful.  Regardless if the humidity sensor turns out to be resistive or capacitive technology, knowing the specification would allow me to design a circuit modification.

Has anyone been able to find the specifications or do your own test on the humidity sensor component used in Aprilaire humidity controllers?

The sensor on my controller looks like this:

The idea that the sensor was based on capacitance is true, but the idea to "design a circuit modification" will not work, because the output of the sensor is digital.
The sensor is from Sensirion and is known as a SHT11:

The SHT1x digital humidity sensor ... As with every other Sensirion sensor type from the SHTxx humidity sensor family, they are fully calibrated and provide a digital output.
The SHT1x humidity sensor series (including SHT10, SHT11, and SHT15) is Sensirion’s family of surface-mountable relative humidity sensors. The humidity sensors integrate sensor elements plus signal processing on a tiny footprint and provide a fully calibrated digital output. A unique capacitive sensor element is used for measuring relative humidity, while temperature is measured by a band-gap sensor. Its CMOSens® technology guarantees excellent reliability and long-term stability. The humidity sensors are seamlessly coupled to a 14-bit-analog-to-digital converter and a serial interface circuit. This results in superior signal quality, a fast response time, and insensitivity to external disturbances (EMC).

It appears that although the chip is calibrated during manufacturing, there is no possibility of changing the sensor's calibration because it's done in one time programmable memory.

The calibration coefficients are programmed into an OTP memory on the chip. These coefficients are used to internally calibrate the signals from the sensors. The two-wire serial interface and internal voltage regulation allows for easy and fast system integration.

There are published projects that use sensors like this one, and it would probably be possible to connect an additional processor, such as an Arduino, then send a serial signal to the humidity controller that followed the protocol of the chip, but really was coming from a program which altered the digital message.  This seems like an awful lot of effort, though.
I suspect that the specs listed above are enough, I haven't covered the serial protocol, but generally, the specifications for the sensor is two wire digital serial communication.
Reference: Sensirion SHT1X Reference Page