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installing hardwood floor in bathroom - subfloor issues

I am remodeling a half bathroom in my 1925 house. I've removed the existing tile floor which I believe was put down about 10 years ago. Under it was 4 planks of the old hardwood near the doorway and 3/4 inch plywood the rest of the way. See the attached picture for what I have to work with now.

I want to continue the hardwood from the hall into this bathroom. What do I do about 1) the missing subfloor around the plumbing and, 2) the joint in the waste pipe which is at least 3/4 inch higher than the old subfloor. The plywood was just put over the pipe and it bulged and was covered with tile. Being under/behind the toilet, I never noticed it until I got the toilet out.

Should I just lay the hardwood over the gaps in the subfloor? What about the waste pipe? Could it be moved so it doesn't bulge above the subfloor? Should I put down a thin layer of plywood and cover with 5/16 hardwood?

I want the hardwood to be seamless from the hallway into the bathroom.

Thanks for any advise.

Re: installing hardwood floor in bathroom - subfloor issues

Plumbing looks nasty, maybe even lead piping. Room's gutted, now is the time to redo it. Switching over to pvc, and going to 3" for the toilet should save you the room.

Re: installing hardwood floor in bathroom - subfloor issues

Agree with the previous poster- change out that plumbing!

Have you considered attaching 1/4" hardibacker to the existing sub-floor, and gluing down an Engineered wood floor to the hardibacker? Both the hardibacker, the adhesive and the engineered wood itself are going to be the best option for a bathroom installation where moisture is obviously a concern.

Good luck!

Re: installing hardwood floor in bathroom - subfloor issues

Ditto jkirk .....
besides consider the humidity the floor will be exposed to if there is a shower in this bathroom.
You might want to check with the flooring manufacturer if they recommend installation in a bathroom and the warranty coverage.

just a thought.

A. Spruce
Re: installing hardwood floor in bathroom - subfloor issues

Aside from a sweaty toilet, I will disagree with my comrades about installing hardwood in a 1/2 bath. The key words being "1/2 bath"! If this were a full bath, then I'd definitely be saying no, but in a half bath the only real water danger is going to be the toilet. As long as the supply lines and the seal at the base are good then the dangers of water are very low. What's most important is that there be no movement in the floor that can damage the wax seal at the base of the toilet. This is an issue with a floating floor because there is a foam pad under the hardwood that has flex and give. In the area of the toilet, do not install the pad, instead use plywood of the same thickness as the pad. This will give you the stable base you need. When I installed hardwood throughout my house, I included the 1/2 bath with the precautions mentioned and never had a problem with leaks or floor movement. Just keep an eye on the toilet that it never becomes loose or wobbly, if it does get the wax seal replaced immediately.

As for fixing the subfloor, what I typically do if I can't use readily available framing is to add in my own around the toilet flange that is attached to the surrounding floor framing with joist hangers. If your maximum span is less than 4', you can use 2x4's, if it's over 4' then use 2x6's. Cut the damaged area out as clean and neat as possible, install the framing so that it supports the loose ends of the existing subfloor, then fill in the hole with new material that is the same thickness as the existing subfloor planks.

Re: installing hardwood floor in bathroom - subfloor issues

Thanks for the info. I am getting a quote to redo the plumbing. Will see what that costs.

This is a half-bath only, no shower, so wood should be ok. The whole bathroom is really little more than a closet :)

Re: installing hardwood floor in bathroom - subfloor issues

If you are putting down "hardwood flooring" not laminated, the gaps in the sub-floor are of no consequence.

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