Cold roofs? Warm roofs?
What’s the main difference between roof construction options? BRANZ explains the science to help you design better roofs.
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What’s the main difference between roof construction options? BRANZ explains the science to help you design better roofs.
Strong wind causes damage to houses, particularly their roofs. A recent BRANZ study started by defining ‘extreme winds’ before developing retrofit solutions to ensure roofs on older houses are adequately secured.
BRANZ was called into a Dunedin school where too much ventilation caused excessive condensation in a large roof space. Understanding why this happened points to warm roofs being better in some locations.
Twenty years ago, roofs didn’t need to be specifically ventilated. Today, things are different. That’s because 21st century homes are more airtight, and if they aren’t aired, condensation may form.
A local volcanic eruption is a substantial risk to the Auckland region. Research into the impact of multiple volcanic hazards on the roofs of buildings showed that they generally deal well with volcanic ash and flying rocks landing on them.
Ventilation of cold roof designs in New Zealand doesn’t always go smoothly. Here, BRANZ physicists hand over to a couple of professional builders who have long been at the coalface dealing with roof moisture issues on their projects.
BRANZ research has provided reassuring results for those wanting to add passive ventilation in roof cavities to counter condensation. Corrosion of metal fixings inside the roof space remains low, even in extreme marine environments.
BRANZ physicists have developed a useful calculation for designers to work out the minimum number and area of vents required in roof spaces.
Recent BRANZ research has confirmed how moisture gets into roof spaces and highlighted the critical role ventilation has in removing it.
In response to industry questions, BRANZ recently launched a research project into corrosion rates in vented roof spaces. Two roof spaces have been built in an unforgiving coastal environment and will be monitored.