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evy's avatar
evy
Explorer
May 21, 2015

Flat window vs curved wall (pictures)

I red a couple of threads about this issue, but in my case my fiberglass walls are slightly less curved then the "normal" OEM Ford van walls,

Take a look at my pictures.

I will be installing two 15"W x 24"H windows, one on each sides, and two 12"W x 20"H windows, one in the rear door (passenger side) and one in the side door (closer to the rear).

I live in Canada so everything is taxed and overpriced (compared to US prices) I will be buying most of my parts in the US but I needed to have the windows now, So I found an RV parts store that had them in hand at an ok price (you tell me) 120$ and 140$ each + 15% taxes.

So there is already a foam gasket behind the exterior window lip, I will be adding another 3/4" wide grey gasket (see pic) they called it "dom dom"
I will be removing the excess grey gasket (24h later) with a razor blade and finally sealing everything up with silicone. Again I have never done this before this is what they told me at the RV parts store. Do you have anything to add?

As you can see from the inside picture with the finishing frame, the 8 screws are all in the back and near the corners, I will add a 1.5"x1.5" wood stud around the opening and finishing off with temporary 1/4" plywood shims, I will be installing the finishing 1/4" plywood when the wiring and insulation is done.

Ok here's a question.
Can I seal the outside of the window like I mentioned earlier and maybe a week later remove the inside frame with the 8 screws, remove the wood framing and the plywood shims, to seal the small gap between the window and the outside fiberglass wall with silicone as a precaution then re-install the wood frame (adding industrial glue this time) + temporary plywood shims.
Once all that is done I can have the inside walls sprayed with 1.5" insulating foam, sealing the outside of the wood frame, so with all these precautions I will lower the chance of any leaks, right?


















Moderator edit to re-size pictures to forum recommended limit of 640px maximum width.


please see the thread titled "Good News for Picture Posting stuck at the top of this forum. Thanks.

4 Replies

  • I replaced the seal strip on my air conditioner last winter. Those seals are extremely thick, but they compress really well and totally fill any gaps. That seal is also fully water resistant. Remember that it seals the base of the AC to the roof. If you use that, it should fill the gap really well and then you can seal the perimeter with something like ALEX from home depot for added insurance.

    Jose
  • Silicone would be OK in this application. It is an excellent sealant in compression between two surfaces, as long as the sun doth not shine on it.

    I'm thinking the best thing would be a butyl rubber gasket, a thick one, and then seal edges on the outside with a urethane or polymer sealant. I like Geocel 2350, a close cousin to Geocel Proflex RV.
  • Silicone would be a bad choice of sealant. Better to use a proper RV sealant such as Dicor (the non-self leveling type).
  • I would remove the foam gasket- use either a foam gasket or butyl tape (dom dom)- not both. The butyl will make the seal- any silicone is purely cosmetic. You will need to use several layers of butyl, enough that it squeezes out the entire perimeter- be aware that the top and bottom will protrude more than they are in the pictures, because the center will be held out by the butyl.
    The interior framing you add needs to be contoured to the wall to give a stable base- the contour will be subtle, but otherwise you will be trying to flatten the sidewall to follow the window.