From the mid-1990s to around 2005, thousands of Aotearoa New Zealand homes were constructed with designs, details, materials and methods that resulted in leaks. In many cases a lack of maintenance made the problem worse. Where rainwater couldn’t drain away, it frequently led to damage in the wall assemblies.
BRANZ research indicates that problems with weathertightness may also exist in buildings constructed since 2005.
Resources for designers and builders
When building a new home, it is up to designers, builders and engineers to ensure that it is weathertight. BRANZ provides information in many different formats about designing and constructing weathertight homes.
-
Building Basics: Weathertightness
This book aims to provide guidance for builders and associated subtrades in the basics of weathertight construction of light timber-framed residential buildings.
View more -
Industry perceptions of weathertightness failure in residential construction
This study report (SR442, July 2020) investigates industry beliefs about why weathertightness issues persist in new residential builds and how these issues can be mitigated.
View more -
BRANZ Research Now
Industry perceptions of weathertightness issues in residential construction. This fact sheet summarises the findings in study report SR442.
View more
Services for manufacturers and distributors
BRANZ can evaluate the weathertightness of different construction systems and building materials through laboratory-based and on-site tests of air permeability, watertightness and wind resistance.
-
Weathertightness testing
We use a range of methods to evaluate the weathertightness of roofs, wall claddings and other external openings such as windows, doors, meter boxes and pipes.
View more -
Building materials performance testing
We use accelerated weathering, ultraviolet (UV) light and moisture exposure to test the mechanical strength retention and durability of building materials and products, including plastics, metals, cement, timber and wood-based materials.
View more -
Building materials durability testing
BRANZ tests the durability of building materials, components, and construction methods to determine if they will remain functional over the 5, 15 or 50 year period required for compliance with New Zealand Building Code clause B2 Durability.
View more
Updated: 5 May 2025