Some of you may have taken the time to watch my video series with Fine Homebuilding about properly installing flanged windows in multiple assemblies. Those methods apply to most windows installed in the USA. However, they don’t apply to flangeless or “European style” windows, including the triple-glazed, tilt/turn windows preferred by many high-performance builders.
Of course, some of the fundamental principles are the same, shingle-style lapping for example, is the only way to detail any window flashing, as well as using a back dam and creating a slope at the sill of the rough opening. In this article I will share how we are installing flangeless windows in the wall assembly that we utilize most commonly. On the project shown here the windows are from Schuco, though many European-style windows install similarly. I would refer to this install as a face-sealed system.
Locating the window in the opening
Over the past five years we have not built a home with a finished wall thickness less than 7 ½ inches. Most likely on our builds that includes 2×6 framing (5 ½ inches) plus ½ inch drywall inside and 1 ½ inch ZIP R-sheathing outside. Warming the wall with the insulated sheathing has become a standard detail in our homes. Having this thick wall gives us an opportunity to make choices about how our Euro-style, flangeless windows are installed.
The window could be pushed outward in the assembly. Like a flanged window, this presents more challenges for water management because the window is closer to the weather. Moving the unit to the interior face of the wall better protects the unit from the elements, but in doing so, also moves the unit away from the sunlight…