Hi, The subfloor in my bathroom is rotten. Not horribly rotten, the underside of the subfloor is my garage ceiling and you can't see rot from underneath. But from the top, I can see pits and soft areas and flexibility in the subflooring boards, which are tongue and groove 1x6's. The rotten areas extend under the cast-iron bathtub and an interior wall. The 2x4 baseplate of the wall has some rot on the bottom. I doubt it's affecting the strength of the baseplate very much. I don't think there's any way around taking out the cast-iron bathtub. I don't know if it's reasonable to take it out whole and re-use it, or if it really has to be just trashed with a sledgehammer to be taken out. I might buy a new bathtub, which would be lighter. But, can I avoid taking out the interior wall? I was thinking that I could remove rotten subflooring boards one at a time, replace them with 1x6 boards, pushed under the interior wall. I would support the ends of the boards by pushing them on top of 2-by-whatever wood, screwed onto the next floor joist (and fastening them there with angle brackets, maybe). If the boards are removed one at a time, I don't think the 2x4 baseboard would sag significantly. I'd use oak 1x6 for strength. The room on the other side of the interior wall has a hardwood floor, and I hope to avoid having to remove part of the floor for this repair. I don't know if suitable 1x6 tongue and groove is available to replace the floor boards. If I got standard 1x6 oak boards, maybe I could rip off 1/4" and substitute them in, but it wouldn't be tongue and groove - I don't know if the tongue and groove is necessary for strength? Can one carve tongue and groove into the boards? Or perhaps it would be easier to take out part of the interior wall, so there's no load on the subflooring in the area that needs to be replaced. In that case I could take out all the rotten subflooring at once and replace it with plywood. I'm not sure how to rebuild part of the interior wall. But maybe it could be done without too much problem. I don't think this is a load-bearing wall, because it is parallel to the floor joists, and it isn't right on top of a floor joist. So I think it is only supporting its own weight. I don't think the floor joists are rotten. If they were, I think I would see the wood rotting from below, and the underside of the subfloor looks fine. So what do people think? thanks Laura

Hi and thanks in advance for any info. Converting a 25x13 garage into living space and when I took all the original sheetrock down I found that on the 2 exterior walls there are two 2x6's used as the bottom sill plate with 2x4 stick construction 16 on center in those walls. The 25' interior wall, on the other hand, has a single 2x4 sill plate with 2x4's 16 on center walls. I want to insulate/re-sheetrock/finish this space and the difference in 2x6 sills and 2x4 walls would cause me to have to start the sheetrock on those 2 exterior walls higher then I'd want if I use the current 2x4's due to the 2x6 sills below. Finally, baseboards and finish molding seems like it would be a nightmare given the differences in sills. What's the best way to handle this? Sister a 2x6 to each 2x4 to bring it to the edge of the bottom sill? Any other suggestions? Unfortunately, facing the current 2x4's with a 2x4 won't do it either. Thx.