Underlay and cavities

Install cladding systems in accordance with manufacturer's requirements, along with documentation from the designer and building consent.

Fixing cladding over a drained and vented cavity is more weathertight than direct fixed cladding systems. Regardless, it must be installed and finished correctly.

• Read more on drained and vented cavity construction: BRANZ Wall Cladding Installation 
• Read more on exterior cladding penetrations: BRANZ Cladding Penetrations

E2 External moisture is the section of the Building Code that relates to external roof, wall claddings and external openings constructed to prevent external moisture from causing undue dampness or damage.

• Building Performance - Building Code E2 External moisture 

Weathertightness design basics

Learn about the four key principles of weathertight design:

• Deflection - how is water deflected from walls and critical junctions?
• Drainage - if water gets in can it drain?
• Drying - if water can't drain, can it dry?
• Durability - will materials be durable if occasionally wetted?

• Read about the 4 Ds of weathertight design: BRANZ The 4 Ds - deflection, drainage, drying and durability 

Learn more about how exterior elements of the building help make up the lines of defence against water.

• Read: BRANZ Lines of defence

Learn how air movement and pressure moderation impact cladding and weathertightness.

• Read: BRANZ Air movement and pressure moderation