Bump on this. I'm in the same boat and wondering if I need a cut out in the carpet and subfloor to access the drain or can I just caret over it.

 

You don't have to raise the drain to the new floor height but it'll look better if you do. You really need to cover the not used drain otherwise smell can enter into the room or the moisture will damage the floor above it. Just trim around the cleanout drain.

 

I sure hope you meant a subfloor that's T & G like Advantec not just reguler square edged OSB.
Your also missing a step, You should not attach glued down tiles to OSB There needs to be a layer of 1/4 underlaymant sanded plywood layed so the seams do not line up with the seams below, attached every 4" on the edges and every 6 to 8" in the field.
Then fill in all the seams and flaws with nongypsom floor leveler or the flaws will show through the tiles.

 

Hi All,

This is my first post. I am finishing my basement and am in the process of putting in my subfloor.

My basement is a level concrete slab with cinder block walls.
I do not have any moisture problems, but am installing a moisture barrier anyways.

On the walls, I first put Drylock.

On the floor I put down 1/2" rigid foam with a 1/4" gap on all sides. I filled the 1/4" perimeter with "Great Stuff" expanding foam. I tuck taped all of the joints and laid them off center.

On top of that I am laying 3/4" treated OSB (nailed down with powder driven masonry nails).

On top of the OSB I am going to be installing vinyl tiles. This part of the basement will be where my wife does laundry.

I have 2 floor drains in the concrete. Both are 4" black PVC pipe. One is used to drain from my HVAC/water heater. Another is not used for anything. (pictures attached).


My questions are:

1. For the drain used by by my HVAC/water heater, is it OK to simply cut out a square in the subfloor for access, or do I have to raise it so the top is flush with the new tile floor?

View attachment 45712

2. The drain that is not used - can I just cover over it with my subfloor? Do I need to do something special to plug it?

View attachment 45713
There is water in the bottom, but I do not plan on using it for anything. If I can't cover it, how can I raise it up and make it level with the tiles?

I also have a standpipe where my laundry and tub drains into.

View attachment 45714

I'd like to avoid calling a plumber.
Thanks much!

--Michael
[/QUOTE

So apparently nobody has an answer. that sucks. I'm in the same boat and the internet is seriously silent on this subject.

 

I know it is an 8 year old thread, but since you breathed life back into it, I don't see the need in a subfloor on concrete. What would the purpose be? If the concrete floor is flat and smooth, install your floor covering directly over it. I would not recommend carpet, but a product like LifeProof LVP. Tile is hard and cold, but it is an option, too. LifeProof comes with its own underlayment attached, so it is a one time shot.

 

About the only benefit for subfloor on concrete would be a tiny bit of extra give.

 

So did you cover the not used drain? I have the same in what's going to be the laundry room.

 

Why would you want a subfloor in a laundry room?

 

Anybody? I would like to finish my basement but there’s a drain right in the middle and the floor slopes towards it. Do I just cover it? Cut into the subfloor?

 

Finish it with what? Don't often see subfloor in basement?

 

@kathrynkerekes Since you are not the OP on this 8 year old thread, where does yours start? You haven't posted any pictures so we don't know what your situation looks like.

 

 

My situation is worse. Small room VERY sloped into the drain. To the point where it's dangerous to walk. I'm going to shim with pressure treated wood and lay the subfloor over that.

 

@Queenfindlay you are responding to a 12 year old thread. THe OP never returned after his first post. If you want better responses, start your own thread and provide us with detailed information and post pictures so we can see what you see.