In new construction, does drywall sit on top of the subfloor or finished floor? Or does it even matter? We are going to be putting in wood flooring and tile flooring in the bathroom.

 

Drywall goes up before the finished flooring goes down.

 

Is this a trick question?

You can certainly put the floor in first if you want, but you will need to protect the floor from all the drywall mud that is going to get slopped on it and all the sanding dust that is going to fall on it. For this reason, if you have a choice, you wait to put the finished floor down until the walls have been finished and painted.

Drywall should usually be kept up off the finished floor in any potentially wet location.

 

Sorry. It's not a trick question. We are renovating a small house and after doing a lot of demolition we saw that there are several areas where the drywall is sitting on the finished wood flooring, yet there are also areas where there drywall is sitting on top of the subfloor. I'm confused why anyone would do this. I'm sure that since the house is so old and has changed ownership a few times, weird stuff happens, but still.

Now, that I know that drywall is supposed to sit on top of the subfloor and not the finished floor... Should I go and try to fix some of these areas so that the drywall sits directly on the subfloor?

 

Probably not worth messing with. All it proves is that the drywall was hung first (while subfloor was the only floor there) and the finished floor was added after the drywall was hung and finished... which is what one would normally expect to see. Anything else can be chalked up to "remodeling".

Your drywall is probably elevated about 1/2" above the subfloor and that is really all that matters. A wood floor is supposed to be kept about 3/4" away from the perimeter walls anyway, so its not like the 2 will ever touch. Baseboard and baseshoe covers the gap.

 

Mobile homes have the interior walls set on the finished floor because it's quicker. I painted for one builder who used to lay his hardwood floors first but he finally seen the error of his ways I wouldn't be overly concerned unless there are other issues.

 

I wanted to emphasize this remark from X:
You want a gap between the floor and the drywall to prevent the drywall from sitting in any spilled liquid. Hence you don't want the drywall sitting on any flooring.

 

Oops. I think we've made a little boo boo. In the process of doing demo on an old house, we did notice that some areas of drywall were installed directly on top of the finished flooring, and like a true amateur that I am thought that this was actually correct. So in areas where we have had to repair and add completelely new drywall, we added drywall all the way to the bottom and thus touching the finished wood flooring.

Now, I guess I need to decide what to do here. I suppose in areas such as the bathroom because of high moisture, do you think I should go ahead and fix it by cutting off a 1/2" of drywall from the bottom? And what about the living room? There is no obvious plumbing and thus no moisture there. Should I bother with cutting off 1/2" of drywall from the bottom?

 

It's best to cut a 1/2" off the bottom, not so much for air borne moisture but for the times that liquid gets spilled [or even aggressive mopping] that might get water at the bottom of the drywall where it can suck it up like a sponge. Use a piece of wood as a guide and make a deep or multiple cuts with a utility knife to remove that 1/2"

 

Ok thanks guys. Just one final question. The small 1/2" gap between the floor and the lower drywall anel that we are talking about... You do mean that this 1/2" gap should exist between the finished floor and the lower drywall panel. Correct? We have hardwood floors as the finished flooring.

 

Yes, although spills can leak thru the hardwood making the gap not as critical. It doesn't have to be a pretty/neat cut at the bottom of the drywall since it will be covered by baseboard.

 

Sheetrock is generally installed from the top to the bottom laterally, anyway, which will leave a gap at the bottom. This gap will be covered by base molding. Normally constructed walls will be 97 1/2" tall above first subflooring (bottom plate, two top plates and 92 5/8" studs)