Dear Dave,
My RV’s window is leaking rain water. Can I fix it with silicone? The gasket is not that old. I bought the RV two years ago, used, and I think they put it on. —Debbie, 2005 Coachmen Freelander Class C
Dear Debbie,
You could try silicone; however, I think it would be best to remove the window and reseal it with the proper sealant, butyl tape. I believe the window is a Hehr product. Since it is 2005, it should be a typical outer window and frame with an inside ring that is fastened to the outer frame which sandwiches the two to the sidewall.
Use butyl tape to seal RV window
Normally all that is needed to seal the window is a putty-like tape, called butyl tape, around the outside frame that sits flush against the sidewall. When the inner frame is connected, it squishes the butyl tape and creates the best seal against moisture. No silicone is necessary, although some companies do run a bead of silicone along the top called a cap seal. All that does, in my opinion, is collect dirt and look bad.
The procedure is relatively easy. Either have someone on the outside hold the window, or apply some of the blue or green painters masking tape to hold the window in place, then remove the screws from the inside. Then you should be able to push the window out. You might have to use a razor knife to cut some of the old butyl tape or silicone, if someone applied that.
Clean off all the old sealant with Goo Gone, which is what I found works the best. This is a good time to inspect the frame to make sure there are no gaps that moisture could penetrate. Then run a new strip of butyl tape around the frame and reinstall.
Again, if applied correctly, you will not need silicone or any other type of sealant.
You might also enjoy this from Dave
Can I seal my RV’s windows without taking them out?
Dear Dave,
Is there a way to seal around the RV’s windows without removing them? Is there a sealant that can be used around the outside of the window that is safe to use with the various exterior wall materials? —James, Coleman 2515RL 2020
Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”
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Silicon does not cure everything. It is just a bad path sometimes.
I have never been satisfied with silicone caulk for any use at all. It attracts dirt. Whenever it must be removed it leaves behind a coating of some sort to which almost nothing will adhere.
People will argue about using silicone saying it is fine and another coat will stick just fine. I agree with you. Once cured, it is impossible to get all the residue off. Some say paintable silicone will work, but I have found it too is very hard to remove. Plus the silicone will not adhere to the butyl. Geocell is the only way to go. I used it to seal the bottom edge of my toy hauler ramp where the frame meets the fiberglass. Still good after 5 years.