How To Air-Seal and Trim an Insert Replacement Window
Your window installation isn't done until you've caulked outside and installed stops inside.
Remodeler, Mike Sloggatt: I like to use foam on all my installations to make sure there’s a good air seal. Just make sure you use a good window and door foam. Put foam along the entire opening, starting at the bottom. Get a good bead. While the foam sets up on the interior, run backer rod around the outside gap of the window to seal it properly before putting on the exterior trim. Even though it will be covered with trim, I tool it a little bit to get a good seal.
This window system comes with an exterior stop cover—a lot more convenient than having to bend up coil and figure out how to cover that space. I need to cut the stop cover at 35 and ¾.
Narrator: Once Mike has installed the stop cover, he runs another bead of sealant around the perimeter, closing the gap between the stop cover and the existing brick mold trim. The sealant is a solvent-based siding and trim caulk. It’s available in dozens of colors to match popular windows and doors. Mike trims the foam with a knife and scrapes away the excess. He uses a molding bar, although any scraping tool will work. Mike trims down the original window stops, removed earlier, to match the thickness of the new window. He dry-fits the stops, starting at the top; then he fits the sides, and finally he secures them with an 18-gauge brad nailer.
Mike Sloggatt: I’ve reapplied the old stops to match the original casing.
All Videos in This Series
Inspect existing windows and measure for insert windows
Shim, level, and fasten the insert window
Air-seal and install interior and exterior trim
