When applying 2″ rigid foam on exterior walls on new construction, how are the windows secured to the plywood jamb extensions?
macarullah
| Posted in Green Building Techniques on
Does the rigid insulation on the exterior negate the need for a poly vapor barrier on the inside?
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"Extension jambs" as you call them should provide for a lumber frame around the perimeter of the rough opening on the exterior sde that is flush with the foam. The window flanges are nailed to the lumber frame, just as you would attach to conventional framing. If the windows do not have flanges, there are steel band clips, the same as are used when installing windows in masonry openings.
You do NOT want an interior side vapor "barrier".
Q. "When applying 2" rigid foam on exterior walls on new construction, how are the windows secured to the plywood jamb extensions?"
A. I assume that the "plywood jamb extensions" you are talking about is the plywood window buck. The window is secured one of three ways: (1) by the window flanges; (2) with steel masonry clips, or (3) with trim screws through the window jambs.
Q. "Does the rigid insulation on the exterior negate the need for a poly vapor barrier on the inside?"
A. Yes. Building codes do not require the use of an interior vapor barrier -- only a vapor retarder.