Description

Considering the key requirements of a plumbing system early in a house design can lead to a smoother consenting and building experience, fewer call-backs and happier clients.

When BRANZ arranged inspections of 200 new houses under construction, some of the most common problems involved plumbing. In over a third of the houses, there were framing cut-outs to accommodate pipes that were larger than permitted in NZS 3604:2011 Timber-framed buildings.

Cladding penetrations for pipes that were not properly sealed to the wall underlay – a potential weathertightness risk – were also among the top 10 defects.

Scope

This article includes:

• Plan well to avoid problems
• Basic requirements
• Design and planning pointers
• Think about the water supply layout
• Gradients and floor joist depth
• Floor waste gully traps
• Drainage, sanitary plumbing and venting a 2-storey house
• Include maintenance access
• Plan the work sequence