What's the best way to repair a leaking window on a home that's surrounded by vinyl siding? Water only comes in during heavy rains. My dining room double-window appears to have a broken J-channel. The subfloor under the middle of the window is rotting/has a hole in it. I assume I have to fill in the hole by the window and possibly fix the J-channel, then pull up the carpet and cut out/replace that section of the subfloor, right?