Flangeless Window Installation Details
We are building a DBL stud wall with 1/2″ plywood sheeting, 1/2″ plywood rough opening. Flangeless Tilt and Turn windows. The wall is only 8″ thick. We will be trimming the exterior with 1×4 PVC trim overlapping the window/rough opening and caulking. This trim will then be the base for roll shutters.
Is there a drawing detail for installation and taping, I didn’t see any in the Library. I have seen limited video instructions.
Is there benefit to using a 12″ flashing tape or product to completely cover the rough opening on the sides and top? My thinking is to connect the vapor barrier to the outside Weather barrier and then seal the windows to this frame for continuity?
On the exterior, would you use vapor permeable tape on all sides or just the bottom? or would you leave the bottom open and seal it from the inside of the window for drainage?
Thanks, I might just be over thinking all this.
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Replies
You should read this how-to article by Jake Bruton: Flangeless Windows Done Right. He explains how he installs European-style windows that sit within the rough opening. He uses a face-sealed approach to water and air management.
> Is there benefit to using a 12″ flashing tape or product to completely cover the rough opening on the sides and top?
Flash the opening to the extent it could ever be victim to water. 'My mantra is, “Flash the rough opening, not the window,”' says Mr. Holladay in this article (https://www.greenbuildingadvisor.com/article/installing-windows-in-a-foam-sheathed-wall) and I agree with him.
> On the exterior, would you use vapor permeable tape on all sides or just the bottom? or would you leave the bottom open and seal it from the inside of the window for drainage?
The 'vapor permeable' aspect of the tape is a red herring; I suspect it doesn't matter much. Leaving the bottom open is important and then following up with the interior seal as you say. My preferred method has become low expansion foam as a backer, which is then trimmed and coated with a robust, flexible sealant.
Thanks guys, After I posted, I just noticed the "Related Questions" section just right of mine and found most of what I was looking for.
Patrick, Thank you for addressing my particular questions. The tutorials do not show any flashing tape or Air/Vapor barrier connecting between the inside of the window and the vapour barrier on the interior wall. It is always just framed or plywood. So that was my ask, what about connecting this junction, does it affect air tightness or moisture? is it necessary