How can I repair a slightly bubbled area on my base floor without removing the carpet padding?
Asked by Maureen Watson 
6 months ago
Last Updated: June 14, 2024
Just had a quick thought… I was peeking under the carpet padding and noticed a little bubble in the base floor. Any ideas on how to smooth that out without tearing it up? 😱
It’s due to moisture. The OSB swells and becomes brittle. You can use rock-hard putty, prime the floor to seal it, or other fillers. It just needs a good filler.
If you just want to make it flat: remove the nails and use a power planer (preferably) or a sander with a low grit to flatten it. Then, renail or rescrew. If you want to do it correctly: determine the cause by examining underneath and correct it based on what you find.
For water damage, simply cut it out and replace it. If you don’t know how, call someone who shouldn’t charge a lot.
😂 Rip it all out if you are going to stay there and replace it with high-quality plywood subflooring.
You guys crack me up, just go over it with 1/4 plywood or adjust the floor level for the whole room. Alternatively, sand it down and fix it enough to put down snap-together flooring, it will be fine, I promise.
Probably got damp too many times before the roof was put on. Cut it out and replace it or use a belt sander with an aggressive grit. I always sand all my seams on OSB here before flooring just for that reason. It will always swell when it dries if it isn’t under a roof or tarp fast enough.
It does seem like water damage, probably from before the roof was installed. Use a scraper to make sure it’s all leveled or below the floor, getting rid of any loose or flaky parts. Fill it with construction adhesive. It’s flexible and sturdy. It doesn’t have to be perfect, but the smoother, the better.