Outie 2x picture frame – some questions
Working my way through the advice in “Installing Windows In a Foam-Sheathed Wall”, https://www.greenbuildingadvisor.com/article/installing-windows-in-a-foam-sheathed-wall, at Step 1 I think I want outie windows, and at Step 2 I think I want housewrap on the exterior side of the insulation. So far so good.
At Step 3 I think I want to go with the 5th option- a picture frame of 2x lumber because to my eye it looks to make air sealing easier. My air control barrier is to be the exterior face of the sheathing. After sealing the seams in the sheathing, membrane (peal-and-stick or liquid applied) would bring the seal to the “inside” surfaces of the rough opening (the sides facing the window assembly). The picture frame would be installed, and the air seal extended with membrane to the “inside” surfaces of its rough opening. And if I were to take the belt-and-suspenders approach and also form an air seal with the interior drywall, that would also be sealed to the rough opening.
Is that likely to work well? Or is there an easier way?
In my case the picture frame will need to extend the rough opening out something like 4-1/2 inches. Would it work to drill 2-1/2″ deep (for example) countersinks and consequently 2-1/2″ shorter screws for attaching the picture frame to the wall studs (so maybe 5″ screws rather than 7-1/2″ screws)? What screw type, size and spacing would be appropriate? I’m planning on a 4 ft x 4 ft or 4 ft x 3 ft window with a nailing flange.
Thanks for your thoughts.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part