We are repairing a water damage situation in our bathroom and have found that the subfloor is rotten all the way through. How do we remove the subfloor under the wall? This is where there is the most damage.
Cut as close to the wall as possible with a sawzall (locate and beware of water and drain lines in the floor) using a metal blade on the sawzall, cut the fasteners holding down the remaining subfloor by running the blade along the top of the joist. This is a tricky cut and may bend up a few blades, but you will be able to pry out the remainder of the floor. Don’t forget gloves and safety glasses.