The 2017 FHB House is a production-built house in a small development of net-zero-ready houses in Wilder, Vermont, all with a focus on affordability and universal design principles. It’s designed to be quickly built and easily duplicated while meeting stringent air-sealing and performance standards and a strict budget.
The windows of choice for the FHB House are by Mathews Brothers. We like triple pane windows because they provide more R-value than a double pane, are less likely to have condensation than a double pane, and there is some added marketing value, as well. We used their Clara Starrett Energy Core double hung windows.
Here’s how we installed and air sealed the windows:
Installation starts with prepping the rough opening. As I mentioned in my post, “Detailing Window and Door Openings,” we start with Zip System stretch tape on the sill. The stretch tape molds into the corners, providing and airtight seal between the Zip System sheathing on the exterior and the Zip System sheathing that makes the jamb of the rough opening.
We continue the air sealing with Zip System tape around the rest of the rough opening. We also add a strip of roof underlayment at the sill that will be used for counterflashing under the window flange and over a clapboard. The window is then dry fit into the opening and the edges of the flange traced on the wall.
A bead of Titebond WeatherMaster Ultimate MP Sealant is applied inside the pencil line marking the flange.
The window is then put in place, plumbed, and nailed off. The strip of roof underlayment visible beneath the window will lap onto the clapboard to direct water away from the wall.
Zip System flashing tape applied over the flanges at the header and jambs.
On the interior, the gap between the window frame and rough opening jamb is sealed with Titebond X-Treme Window and Door Foam. Once dry, any foam proud of the window is shaved off.
Tescon Vana Tape is applied to the window frame and rough opening jamb on all four sides as one final step to air seal.
I suppose if air still finds a way to get through all those barriers I’ll concede defeat. But so far, I’ve noticed that this method is a very effective approach to air-sealing windows. It does take more time than the “old way” of installing windows, but then again, taking an extra step or two to ensure a quality, air-tight installation always does. It’s worth it in the long run.
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I see you used a double hung window. I thought double hung and sliders are the worst for air sealing. Casement and hopper style windows the best. So inform me what's happening here.
Thanks
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I see you used a double hung window. I thought double hung and sliders are the worst for air sealing. Casement and hopper style windows the best. So inform me what's happening here.
Thanks