Ok here's the situation:

3/4" solid prefinished red oak 3 1/4" wide going over 3/4" T&G subfloor which is on joists 16 OC. Full basement, installation on first floor.

I've taken up the carpet in two rooms so far, the dining room is pretty near flat, but has some urin stains from a previous owners dog - and maybe a couple from our dogs before we got them trained. The other room - the office - has a couple stains also and has two peaks at seams of the subfloor panels. The one is about a foot from a wall and slopes down about 1/4" to the wall...another high seam is in the middle of the room and was a little over 1/4" high.

I've been able to sand the seams down (by hand!) a a little and would continue to do this if im' on the right track (its two small areas and I don't mind the work if it fixes it - since I don't have a power sander.

I have two main questions:

1. My installer says he'd replace what stained subfloor he could and treat/seal the rest (if they are under the wall, etc) - I thought initially that replacing the panels is the sure fire way of getting rid of the possibility of odor, but since it is T&G now, would replacing the panels weaken the subfloor? SHould I have him treat the existing panels instead? Or will the non-t&g panels be just as strong?

2. How do I know how far I should sand the high seams down before resorting to filling the surrounding valleys with roofing felt? At what point do i weaken the subfloor by the sanding of the seams?

Thanks in advance for your advice! This is a very helpful forum!

Steve

Hi Steve,

You say your existing subfloor is 3/4" T&G but you don't say what it is. Is it 4x8 plywood panels, OSB or T&G planks? IMO, it is NOT necessary to replace subflooring due to stains from urine UNLESS the subflooring is badly delaminating. All you need to do is paint over those stains with Zinser shellac/primer sealer. This will block out any odor from escaping. You may wish to do two coats. Also, covering it with asphalt felt then the flooring should stopped any odor from escaping. There is also a product called "Urine Off" available at flooring distributors but I haven't tried it. As for the high spots, it is easier and better to sand them flat as opposed to raising up the surrounding areas. Get a power sander OR use a block plane or a course rasp. This will remove the overwood much faster. If after you've done your best, let the installer address any high/low spot issues. Or ask him to do it now and pay for it. It sounds fairly minor. I would take me maybe ten minutes using my edger and some 20 grit sanding discs. I'd avoid removing subflooring unless it's rotting, delaminated or in some other way faulty. The odor can be contained fairly easily.

Thanks Gary - sorry forgot to add yes, it's 3/4" Plywood 4x8 Sheets

The urine stains are large, but don't seem to have compromized the plywood at all. I'm mainly interested in getting out any hint of odor that may (even if human noses don't detect it) trigger our dogs to "re-mark" the territory once our new floors are in.

As for the sanding, our installer seemed to think there was nothing to do - he wasn't recommending we do any flattening - he was going to just nail down all the boards tight and install. But for me, 1/4" is too much of a bump.