NZS 2295:2006 Pliable, permeable building underlays

Builder building a house

Standards New Zealand and the P2295 committee are seeking feedback on a draft amendment to NZS 2295:2206 Pliable, permeable building underlays.

NZS 2295 is intended to provide practical guidance for manufacturers and importers of underlay material intended to be used in New Zealand, and for users specifying underlay to select the appropriate products.

Amendment No. 1 of NZS 2295 Pliable, permeable building underlays was driven by the need for a standard that reflects up-to-date test methods and products that are currently in use within the New Zealand building industry. NZS 2295:2006 was developed and allowed the use of synthetic underlays limited, however, to use in walls. Further research and in-service performance with synthetic roofing underlays has since been completed and reviewed.

This amendment incorporates the following changes to the previous editions:

  • inclusion of performance requirements, related test methods, and limitations of use for synthetic roofing underlays, including deletion of W1 class due to non-use
  • minor changes to specifications and limitations for wall underlays, including deletion of W1 class due to non-use
  • updating reference documents.

The P2295 committee wishes to ensure that synthetic roof underlays introduced into the New Zealand market have properties appropriate to the range of conditions found in New Zealand buildings. The committee is undecided about whether the proposed new ‘retention of condensate test method’, or some variant of it, is the most appropriate means of ensuring condensation on the underside of the underlay is safely managed, at least for synthetic roof underlays.

The committee wishes to use the public comment process to engage with and draw on New Zealand and global researchers and building practitioners’ knowledge and experiences to assist with this decision.

You can view or download the draft amendment on the Standards New Zealand website. The closing date for comments is 27 January 2017.

Published in building.