Description

Using 140 mm framing in external walls allows for a better insulated, warmer home and has practical advantages on the building site too. There are different requirements for 140 mm and 90 mm timber framing to be aware of.

A second insulation-related benefit is that the extended overhang possible with a 140 mm bottom plate makes it easier to specify insulation around the vertical slab edge (see Figure 1). BRANZ research has found that vertical slab edge insulation can greatly improve thermal performance. The tables in Appendix F of H1/AS1 give construction R-values for a range of slab floors incorporating R1.0 vertical slab edge insulation.

Scope

This article includes:

• The 90 mm and 140 mm Code differences
• 140 mm framing vs other options
• An investment with a decades-long return