When to use 住在 and when to use just 住? I have encountered the following sentences:

以前人们住这样的房子
现在人们住这样的房子

Why do these sentences NOT use 住在? I have learned that 住 takes 在 in order to take the location noun after that.
Or maybe is it a chance that 住 carries completely different meanings from  住在, and the both are grammatically correct?
I am a native Chinese speaker. We say "住这样的房子" or "住在这样的房子里". These two are both correct, and they mean the same thing. 

"住在这样的房子" sounds wrong to me."住这样的房子里" may be correct but sounds weird.

As you may have already known, the time "以前" or "现在" do not affect the form of the verb.

Hope this helps!