Insulated external structural sheeting

This type of sheathing attaches to the exterior of the building and can carry an R-value factor, thus breaking the thermal bridging. Products like R-4HP from Building Products of Canada (BP) and Neopor from BASF Canada are available. If seams are sealed as part of an overall system, these can be an effective air barrier. Even taping the seams of external rigid foam plays a part.

Cost, and the time and training required to install materials correctly.