- Build a wooden framework on top of the entire outside wall to hold the insulation and support the new siding (see Figure 7-10). Ensure the air and vapour barriers are properly installed.
- Alternatively, a lightweight frame wall (such as a Larsen truss) can be hung from the rafters or supported on a bottom plate out from the old wall. This would allow two layers of snugly installed batt type insulation, one horizontally behind the frame, the other vertically between the studs. Using this method, RSI 3.5 (R-20) or higher can be installed.