The NZ Metal Roof and Wall Cladding Code of Practice is a comprehensive design & installation guide, and a recognised related document for Acceptable Solution E2/AS1 of the NZ Building Code.
Internal air quality is a major cause of respiratory illness, which has been reported as costing the country $6 billion per annum, with respiratory-related illnesses accounting for one in ten of overnight hospital admissions.
Dust mites grow up to ten times faster in damp environments and contribute to allergic reactions and asthma.
The most recent BRANZ Home Condition Survey identified mould ranging from moderate to severe in 22% of New Zealand houses. Mould was worst in rental accommodation, where much of our most vulnerable population live.
In addition to the health effects, excessive internal moisture impacts material durability. In the roof space, this can affect the roof cladding, underlay, purlins, trusses, fasteners, and seriously affect the durability and structural integrity of those components without being apparent to the occupants.