Literature Review on Building Envelope, Heating and ... - Beeshive.org

Upgraded Thermal & Air Tightness Wall Systems
The Canadian Home Builders’ Association (2001) described wall systems with upgraded
thermal performance and strategies to ensure air tightness as well as moisture
performance as compared to conventional 38 x 139 mm (2 x 6) framing constructions.
Similar wall systems are described in the builders’ reference manual prepared by the
Alaska Craftsman Home Program (ACHP, 1995):
• single stud walls with exterior insulating sheathing;
• single stud walls with interior strapping;
• double stud walls;
• standoff walls;
• rigid insulating core panel walls;
• stress-skin panels; and
concrete wall construction.
Single Stud Walls with Exterior Insulating Sheathing
A rigid or semi-rigid insulating sheathing board is added on the exterior (Figure 1), with a
membrane or rigid air barrier system. A balloon-framing method could be used to reduce
thermal bridging. For a 38 x 139 mm (2 x 6) framing, minor modifications to standard
construction practices would include the following.
• Space studs on 600 mm (24 in.) on centres.
• Replace structural sheathing with diagonal wood or metal bracing and insulating
sheathing, except where structure sheathing is required.
• Recess header joists to allow for higher insulation level at the joists.
• Install continuous vapour and air barriers.
• Upgrade insulation between the studs. Spray-type insulations provide a uniform
insulation level and reduce air leakage. High-density spray-type insulations may
provide higher thermal resistance per unit thickness than batt-type insulation.
PERD-079: Task 2 - <strong>Literature</strong> <strong>Review</strong> 13