Description

Warm roofs are becoming popular – not just for commercial buildings but for residential houses too. What’s the science behind them and how should they be installed? BRANZ found answers by retrofitting an existing residential house.

Recently, BRANZ retrofitted its ventilation test building with a warm roof:

Roofing rethink: warm roofs, healthy Kiwis - Build 202 (2024).

The project sought a practical and straightforward way of retrofitting residential dwellings so they could benefit from the warm roof methodology alongside new-build homes.

Regardless of whether it’s a new or retrofitted roof, planning is important. It’s necessary to understand what a warm roof is and the different ways of building them to see if the method can be used in your project.

Scope

This article includes:

• What defines a warm roof?
• Air and vapour control
• Different options
• The key challenge
• Each layer has a role
• Winter results from the ventilated deck