Warm roofs: Understanding recent trends in NZ

The focus of this project was to identify current developments in warm roof systems and construction techniques. BRANZ roof research over the last years has concentrated on cold roofs and passively ventilating these to minimise moisture risks. This scoping project enabled BRANZ to better understand warm roof system technology, its benefits, potential shortcomings and recent developments. As part of the research, BRANZ also estimated the embodied carbon footprint for a number of common warm roof systems. <br><br>Warm roofs have the potential to improve the performance and resilience of New Zealand educational, commercial and residential buildings by improving thermal performance and avoiding condensation issues. Essentially, a warm roof is a bonded sandwich with an outer waterproof shell, thermal insulation in the middle and a rigid inner sheeting (often metal). Warm roof designs are becoming more popular in New Zealand. A better understanding of warm roof systems available in New Zealand assists both the Ministry of Education and MBIE. It informs their decision making in choices around warm or cold roof systems. Schools would benefit from warm roof designs as they have suffered from moisture problems with cold roof construction. This project tied in with results of previous work and field studies where we have seen that, even with vented roof cavities, moisture issues cannot be avoided under all circumstances.