I have some French doors that have been leaking for sometime, when we took the current doors out and opned the Subfloor up, the rim joists under each side of the door frame was rotten along with about 4 inches of the 2x4 bottom plate. Luckily the sill plate is great and untouched and so is the joists. My Contractor I hired decided not to replace the rim jpoists as he said he couldnt get to it, he formed and poured concrete under each door frame. My new doors are coming I am putting in a Jam sill along with BUTYL flashing to try and prevent this again. MY biggest worry is the rotten Rim joists, Im afraid if water does penetrate it will just run between the concrete and subfloor creating a buckling of the floor also this concrete stops short of the Basement ceiling, I sure dont want it dripping on it. Anyone have any Ideas or seen this done. I have time to get the concrete out and do it myself right Before the door arrives.