I am installing a new window where the surrounding sheathing is Gyplap – an exterior GWB product. I want to air seal the new window to the surrounding Gyplap because beyond that, running behind the brick cladding is some kind of tar paper that doesn’t seem to be well sealed. Are there any recommendations for adhering building paper like Tyvek to the Gyplap paper surface? Just looking at DuPont website for example, there are so many tape/flashing products, I’m not sure which ones, if any, would work well with or are designed for a paper surface.
Replies
I’d imagine any flashing tape with and acrylic, pressure-sensitive adhesive would have no problem adhering to the paper. But as it’s old paper and possibly contaminated, you might want to prime the surface to ensure the tape sticks to it. Something like Tescon Primer RP, which is made for situations like yours, or even Gardz, which you can probably find at your local paint or hardware store.
If you are talking specifically about the Gyplap surface I suggest you use a liquid flashing product. Since paper is porous liquids will stick because they tend to wet the surface they are applied to.
Personally I would use Prosoco R-Guard. It comes in a sausage tube and also in a standard caulking tube. Check any of the Matt Risinger Build Show videos on YouTube. Use the search term R-Guard, or maybe "water sealing a new window installation". Matt does a demonstration on his own house. There is also a Prosoco product called Air Dam that is used on the inside to seal the window frame to the jamb along with a backer rod of foam that you press into place and then use the Air Dam. Using a backer rod prevents a mass of sealant because you want a seal that can move in and out but stick to the jamb and the window frame