External Moisture Penetrations

This section should be read in conjunction with External Moisture and Flashings.

A penetration is any hole cut in a roof or wall cladding to accommodate projections such as pipes, ducts, chimneys, roof lights doors and windows.

This section focusses on roof penetrations only. The type of penetration design is determined by:

  • the size of the hole,
  • shape,
  • the roof pitch,
  • the type of roof,
  • the catchment area,
  • placement on the roof, and
  • aesthetic requirements.

Designers are urged to consider what type of penetration design matches the building application and their customer’s needs, and detail accordingly, rather than allow the installer to make an on-site decision.


See it in action with Roofguide

Many of the penetration details in the Code of Practice are expanded on with step-by-step, interactive 3D instructions in the RANZ Roofing Guide, developed by the Roofing Association of New Zealand in association with the NZMRM.

Works on desktops, laptops, tablets and phones.

Clause Number: 
Revision Category: 
2 - Editing and rearrangement
Revision Detail: 

New referral to RANZ Roofing Guide for further information.

Draft Clause: