This vinyl bow window was installed about 15-20 years ago:
Overall it looks and works OK, but the underside is wood and has severely rotted around the outer edges:
Here's a detail of one corner. There is a cut hole in both outer corners, with what appears to be a rusty bolt head visible inside. The wood appears to be plywood, and around the outside edge it has rotted to the point that you can easily break it away with your fingers. My guess is that this is due to water wicking back along the underside of the window when it rains, and it should have been constructed or flashed differently to avoid that.
How should this be repaired? In particular:
- Is it possible to disassemble and replace the rotted piece from the outside in a bottom-up approach, or would you remove the inner window sill and work downward?
- Is this even repairable or does this effectively guarantee there are deeper problems with the window?
- How would I prevent this rot from occurring again in the future?
Best Answer
Due to its age, I'd leave it & paint it a few times after a stain blocking primer. To correct it, just caulk & nail or finish screw a shoe molding onto the white outside edge to stop & eliminate the capillary action. A pre-drilled PVC molding would be perfect for this.