In replacing a bathroom shower stall, we are replacing a piece of sub flooring with your typical shower damage to it. In replacing it, I noticed the exterior wall which runs parallel to the joist is only half on the joist itself. It went joist, subfloor (part of which is being removed, bottom plate. See illustration attached. Is it safe to be half over the joist with an equal width of old subfloor between it and the joist? Ideally, I'd like to box in a frame between the new joists to support the new subfloor panel, but that would not go under the bottom plate.