NZ Construction News (Jun / Jul 10) Accepted! A Concrete Acceptable Solution for E2 External Moisture of the NZ Building Code

01 Jun 2010

Accepted! A Concrete Acceptable Solution for E2 External Moisture of the NZ Building Code

Rob Gaimster - Cement & Concrete Association of New Zealand (CCANZ)

Some time ago in this column (Unacceptable Not To Have An Acceptable Solution - Concrete Masonry and the Building Code. July 2009) I lamented the fact that the concrete industry, along with house builders wishing to benefit from concrete masonry’s weathertight credentials, were seriously disadvantaged by the absence of a concrete masonry Acceptable Solution (AS) under Clause E2 External Moisture of the New Zealand Building Code.

Well, I’m pleased say that as a result of assistance from the Minister for Building and Construction, along with the support of organisations such as the Registered Master Builders Federation (RMBF) and BRANZ, not to mention more than six-years of lobbying by CCANZ, this frustrating situation is about to be remedied with the development of E2/AS3.

Complementing the Department of Building and Housing’s (DBH) on-going review of the Building Act and work currently underway on E2/AS1 (for traditional lightweight construction), the timely development of E2/AS3 is firmly in-line with the National-led Government’s desire to reduce compliance costs, streamline consent processes and remove what it considers obstacles to the building sector’s productivity.

The primary reason for the lengthy period involved in obtaining agreement to proceed with E2/AS3 has ironically been that as concrete masonry, and concrete in general, do not have a weathertightness issue, policy makers have seen no reason for an AS.  While at a certain level this may appear logical, it has led to a worrying situation amongst Building Consent Authorities (BCA) across the country, which in certain instances has increased compliance costs and impeded the consent process.

The periodic refusal of increasingly risk averse BCAs to grant consents for concrete masonry designs, on the basis that the Building Code does not contain an AS for concrete masonry weathertight, has resulted in inconsistencies between those BCAs that have adopted a pragmatic approach and those that have chosen an overly cautious and prescriptive interpretation of the regulations.  This has made it increasingly difficult for the weathertight advantages of concrete masonry systems to enhance New Zealand’s building stock.

The development of E2/AS3 will however, contribute greatly to alleviating BCA uncertainty in the area of weathertight concrete masonry design, and in turn allow for a more inclusive range of building materials from which builders, designers and their clients can choose.

Unlike E2/AS1 and E2/AS2 Earth Buildings, E2/AS3 will be a CCANZ document, separate from, but referenced within the New Zealand Building Code.  It will also be sufficiently broad in scope to incorporate not only solutions for concrete masonry weathertightness, but also solutions for tilt-up and precast concrete weathertightness.

CCANZ has assumed E2/AS3 project management responsibilities for the development of a suitable and robust technical solution for concrete masonry weathertightness, and is currently liaising with industry through a working group comprised of representatives from stakeholder groups.  Following the September 2010 completion of the technical solution, DBH will undertake management of the E2/AS3 public consultation and implementation processes, with publication scheduled for around March 2011.

During the interim, the New Zealand Concrete Masonry Association and BRANZ publication, Concrete Masonry: Guide to Weathertight Construction ( is available for free download, and provides designers with access to a comprehensive set of instructions that provide weathertightness for all applications of masonry.

The decision to proceed with the development of E2/AS3 can only be described as a positive outcome across the board.  Not only does it demonstrate the acumen of a Minister dedicated to reaching workable solutions to thorny issues, but also the benefits achievable through pan (construction) industry discussion and cooperation. The E2/AS3 documentation of weathertight solutions for different concrete systems will remove any inequitable practices, intentional or otherwise, on the part of BCAs, and in turn afford those wishing to build comfortable and strong concrete homes every confidence and opportunity to do so.