Window in insulated wall

Windows can be installed in line with either the exterior or the interior surface, or in the middle of the rough opening, as shown in Figure 11, in walls, including highly insulated wall assemblies that may be dimensionally thicker than conventional walls because of added insulation. Installing the window in line with the interior wall will help to reduce the potential for condensation on the glass as it is in a warmer location but may require deep sill flashings and window trims on the exterior.

This reduces window exposure to wind-driven rain but relies more on flashings to deflect water. Installing the window in the middle of the wall, as shown, requires less exterior flashing and trim, and provides space for an interior window sill.

Garage doors that separate heated garages from unheated space or the exterior must be weatherstripped. Fireplaces must be equipped with doors or enclosures to restrict air movement in the chimney when the fireplace is not in use. These improvements are not air barriers, but should help to reduce air leakage.

Figure 11

Window in insulated wall

Source : Canada Mortgage and Housing Corporation (CMHC)