Exterior Wall Insulation
The minimum insulation requirements for exterior above-ground walls has increased to a minimum RSI value of 3.85 (R22). This requirement can be met by using 2x6 wall construction and high-density batt insulation, which will yield an in-wall-cavity insulation value of RSI 3.85.
Increasing the insulation values for exterior walls helps to control heat loss through the ‘building envelope’, which is any surface of a building that is exposed to the outside elements. This requirement even helps to keep homes cooler in the summer, reducing the need for air-conditioning in the summer. To find out more about how the Green Homes Program addresses the insulation effectiveness of the entire building envelope, view Basement Wall Insulation and Window Performance.
By-law Language:
Table 9.25.2.1. Minimum Thermal Resistance of Insulation RSI, m² °C/W for Buildings of Residential Occupancy Forming Part of Article 9.25.2.1. |
||
Building Assembly |
Value Required |
|
| Attic Spaces | 7.0 |
|
| Roof Joist Assemblies (Cathedral Ceilings/Flat Roofs) | 4.9 |
|
| Frame Walls (including frame crawl space walls) | 3.85 |
|
| Concrete or Masonry Walls (other than foundation walls) | 2.1 |
|
| Suspended Floors | (Framed) | 4.9 |
| (Concrete Slab) | 2.1 |
|
| Foundation Walls | 3.85 |
|
| Concrete Slabs on Ground at, above, or below grade (insulation under all slab area and around edge of slab) | 2.1 |
|
| Radiant Heating Suspended Floor Assembly Over Heated Area (insulation between heated floor and heated area below) | 2.1 |
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