Hey everyone! I'm noticing that the exterior caulk on my windows has really worn down, and I have a few windows and sliding doors that are showing a weird tan or rust color underneath the siding. I think this might be caused by water getting in—what do you think? I've attached a couple of images for reference.
In the first image, you can see where I think I definitely need to caulk, marked with red lines. But I'm also wondering if I should be caulking the areas marked in blue, where the flashing or siding connects to the window opening. Any tips or advice on this would be really appreciated!
2 Answers
Yeah, you're spot on with the red lines! Those are definitely areas that need caulking, assuming your windows were installed right and the J-channels are doing their job. Just make sure you use the right caulk and prep everything properly; trust me, it makes a big difference. Some caulks just won’t stick well to old ones, so take your time with prep work. It’s so worth it in the end!
Absolutely! Spend some time prepping by removing old caulk and repainting where necessary. You’ll thank yourself later because applying new caulk is super quick once the prep is done.
Make sure to remove all old caulk first. You can clean the area with a little acetone to get it ready; just test it on a small spot first to ensure it doesn’t ruin anything. I recommend using a paintable white silicone caulk and smoothing it out with your finger and some water. DO NOT use Alex caulk—stick with something that binds well!

I totally agree! You might want to check if the installation was done correctly, though. If there’s a noticeable gap between the window and the siding, it’s definitely a good idea to caulk it up to prevent any rain from seeping in.