LISTEN...

Applying air barriers and insulation to the exterior of an existing building is going to change the thermal and moisture behaviour of the assembly.

IMPORTANT CONSIDERATIONS:

• DRYING POTENTIAL INSIDE AND OUT - Allow for materials to dry toward the interior AND the exterior.
• MOISTURE PERFORMANCE - A material applied to the exterior is going to get wet. Plan for durable layers that shed moisture easily.
• FIRE RESISTANCE - Plan for materials that resist the spread of fire and/or have a multi-hour fire rating.
• DURABILITY - Plan for materials that will last for the life of the building (or longer!) and think about the recyclability or reuse.
• USE FLASHING and MEMBRANES TO SHED BULK WATER!

The object of making a building airtight is to prevent air leakage and moisture transfer into assemblies. Additionally, putting insulation on the exterior is an effective way to improve the thermal performance of an existing building.

But be aware...depending on your climate zone, you'll need to add a specific thickness of exterior insulation to keep the original structure warm and to prevent moisture condensation inside the assembly. Ask your energy advisor for help in planning the proper sequencing of control layers.