Description

BRANZ regularly receives queries about hold-down fixings to the exterior walls of timber-framed buildings. This overview sets out the fixing requirements in NZS 3604:2011 for resistance to uplift for the various framing members.

In high wind conditions, roofs are subject to powerful uplift forces. Both the roof and its framing must be securely fixed, so the uplift forces travel down through the building structure to the foundations.

Where a roof is supported by a lintel over a window or door, it is critical that the load is properly transferred around the opening.

However, it can seem strange to have multiple straps and other hold-down fixings on exterior walls of timber-framed buildings where there are openings in the wall and none to other walls where there are no openings. Is this correct?

Scope

This article includes:

• NZS 3604:2011 is an Acceptable Solution
• Roof fixings
• Fixings in walls
• Openings in walls
• Fixing the bottom of walls
• Proprietary fixings available
• Distribution of fixings can seem uneven
• Cheap to add more
• These are minimums, you can do more