LISTEN...

When you add an air barrier and extra insulation to the exterior of a building, you'll be dealing with windows and doors that are now inset into the wall instead of flush to the surface.

If your window or door unit is of decent quality, the primary task is to make sure that the installation is well insulated, air sealed and without thermal bridges.

Installing exterior insulation includes refitting the opening units to the new thermal boundary, and provides an opportunity to improve the installation conditions.

What do you do here?

• Pulling windows flush to the interior means that you have to install deep flashing on the exterior to make up the difference. This is challenging to do correctly.
• Pushing the windows flush to the exterior means that you'll have a deep window well on the inside, requiring a structural window "buck" and extensions on window and wall finishes.
• Setting the window in the middle of the opening creates a compromise between deep window seats and deep flashing.

Providing for a thermal break requires planning. Remember the 'levels of intrusion' - how much surgery do you want to do...and how much can the owner afford?