Window Caulk

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ktzrv

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Joined
Apr 28, 2021
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8
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Pittsburgh
I noticed on our new to us rv, that none of the windows have any caulk around them. Is this normal? The windows are sealed with butyl tape, but then there isn't any caulking around the window.

So, tell me experienced RV'ers. Do your windows have caulk around them?
 

Rene T

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May 20, 2011
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Farmington NH
The rv’s I’ve had always had a small bead of clear silicone caulk on the top and down a couple of inches on both sides.
 

ktzrv

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Joined
Apr 28, 2021
Posts
8
Location
Pittsburgh
The rv’s I’ve had always had a small bead of clear silicone caulk on the top and down a couple of inches on both sides.
That's good to know. We had a superrr small leak in one window the first time we took it out and after further looking realized that there is zero caulking on any of the windows. Not even clear caulk. I think I will apply some caulk to the windows for some extra water proofing. It can't hurt, right?
 

Gary RV_Wizard

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Feb 2, 2005
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At our Silver Springs FL home
The window frame is leak-sealed with a caulk or butyl tape under the frame, between window and sidewall. That's the primary waterproofing. Then a bead of clear sealer of some sort (silicone is common) is applied along the exposed top edge and some/all of the side to avoid water attempting to seep underneath the frame. [Frameless windows don't have this secondary seal.] The bottom edge is left unsealed so that any water that does get under can run back out.

Leaky windows require that the frame be removed from the sidewall and cleaned up, then a new under-frame seal applied.
 

ktzrv

Member
Joined
Apr 28, 2021
Posts
8
Location
Pittsburgh
The window frame is leak-sealed with a caulk or butyl tape under the frame, between window and sidewall. That's the primary waterproofing. Then a bead of clear sealer of some sort (silicone is common) is applied along the exposed top edge and some/all of the side to avoid water attempting to seep underneath the frame. [Frameless windows don't have this secondary seal.] The bottom edge is left unsealed so that any water that does get under can run back out.

Leaky windows require that the frame be removed from the sidewall and cleaned up, then a new under-frame seal applied.
Thanks for this info. I put a little bit of caulk on the window and if that doesn't work then I will remove the window and put new butyl tape to create a new seal on the window.
 

Kirk

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Oct 30, 2005
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191
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Full-time , Escapee
The addition of that bead of caulking along the top and usually at least partially down the sides of the windows was first introduced to prevent the black streaks that rain would make when it ran over the butyl tape that is a dark color and then down the sides of the RV. It may add somewhat to the life of the seal from that butyl tape, but that is secondary to the original purpose of it. Even today there are a few RV manufacturers who do not do so, but if it were mine I would clean it well and then do the job myself as those black marks are a bear to remove.
 

ktzrv

Member
Joined
Apr 28, 2021
Posts
8
Location
Pittsburgh
The addition of that bead of caulking along the top and usually at least partially down the sides of the windows was first introduced to prevent the black streaks that rain would make when it ran over the butyl tape that is a dark color and then down the sides of the RV. It may add somewhat to the life of the seal from that butyl tape, but that is secondary to the original purpose of it.
Oh, that's interesting!

After caulking the window and replacing the gutter, all of our leaks have stopped. If it ever starts to leak again I will just remove the window and replace the butyl tape in the window. This should hold us for a little while.
 
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