How can I repair bubbled paint and drywall around a leaking bay window that has caused damage over three years?
Asked by Olivia Le Gall 
3 months ago
Last Updated: June 18, 2024
So, when we moved into our house three years ago, we didn’t realize that this window was leaking. Now we’ve got some bubbled drywall and probably some rotted trim to deal with. I’ve already sealed up the window with some clear sealant, so no more water is coming in. But I’m not sure how to fix the bubbled paint and drywall around the bottom and side of the window trim, especially the area where the paint has peeled off. It’s a bay window, so that crease you see is actually a part of the wall structure itself. Any thoughts on how to tackle this? 
Begin by scraping off any loose material. You may need to seal it with a primer or drywall sealer if the paper is exposed. You might also have to replace the paper tape in that corner. Watch a few youtube videos on drywall patching for guidance. Take your time layering and sanding between coats until it’s smooth and even. Then prime and paint.
If you’re concerned about rot around the window, try removing the lower window trim to take a look. If necessary, you can remove a small piece of drywall, as it’s hidden under the trim. For the corner, just tape and spackle, then caulk the baseboard if it’s not rotted.
Is the window on the ground floor? If so, it’s not too serious. If it’s upstairs, check the area below too. It’s also a good idea to inspect behind the plaster for any signs of rot.
We removed a windowsill with decay for the same reason and found that it was connected to the moisture issue we were experiencing downstairs, which wasn’t directly underneath. It could possibly be due to a lack of ventilation, so we ended up renovating the entire room and will need to address the downstairs wall too.
Fix the window leak from the outside first, then move on to the interior repairs
I’d recommend sealing the window frame and the seal on the interior of the window
The exterior appearance may not be affected by the mold, but you might need to reseal the interior.