Purchased my first property a couple of years ago. trying to finish an unfinished space, but need to resolve the water issue with the french doors/deck above. Was naive (and the inspector did not write up) a bad french 2nd floor door/deck combo. Looking at a fix. Basically french door looks gone, 2nd flor deck is bad, and the sheathing (unfinished basement) directly below the deck looks roted. Possible floor joist and rotted subfloor beneath french door. How big of a DIY is this? Contractor quoting 10k (reasonable?) to replace french doors (properly flash), move deck and replace deck (properly flash), remove siding and replace sheathing. Photos attached any thoughts greatly appreciated