Just started a bathroom renovation in my (new to us) 1961 ranch house built over crawlspace in NC. I planned on new floor, new vanity & sink, new toilet, but I want to keep the cast iron enameled tub and the tile surround on the walls above the tub. The old flooring consisted of 3 layers of linoleum, and a 23/32 plywood underlayment. The subfloor is diagonally laid 1x6 planks over 2x8 joists roughly 16" on center.
After I took up all the linoleum, it was clear that there was flooring water damage in the tub x wall corner on the side w/the showerhead. The underlayment was shot, and so was the subfloor plank in the corner. I trimmed the damaged plank off at the nearest joist and blocked the 2 joists w/2x6. But...turns out that the rot got to the bottom plate of the interior bathroom wall too. There's about a 10 inch stretch of the bottom plate w/moderate to severe rot. This particular bottom plate runs parallel to and directly above two doubled joists (not sure what to call them...they're not fastened but they are set less than 1 inch apart). By visual inspection in the crawlspace there is zero rot on the joists
The problem is...part of the rot is located behind the tub. Again, I'd rather not take out the tub or the tile surround above it. Below is a picture of the bottom plate damage. Any ideas or advice? Can I repair the bottom plate rot and keep my tub & tile?