Olds: Unfair to compare current external plaster facade systems with outdated building systems of 10 years ago


Bold, world-first innovations, and thorough testing with mandatory technical assistance to each project nationally sets Rockcote & Resene Construction Systems apart from the rest.

I confidently recommend plaster as an effective medium for protecting future projects — and I have science, technical support, processes and qualified tradespeople on my side to ensure plaster as an exterior solution exceeds all expectations.

First things first — the construction sector weaknesses discovered in the late 1990s and 2000s tarnished plaster products like no other.

They changed the face of the construction sector forever, with sweeping changes to the building code and responsibilities held by individuals in how they applied products and skills to a project.

Second — it’s unfair to all concerned that the external plaster facade systems and external facades and cladding of 2015 are still compared with the outdated building systems and general construction practices of 10 years ago.

When it’s written, much is stated that plaster is the cause of construction sector issues when, in fact, plaster, to a very large degree, was the “visual” result and not necessarily the cause.

In turn, the obvious first port of call was the plasterer rather than the cause, which could have been many and varied — such as poorly installed deck membranes, roofing, detailing, incorrect ground levels — the list goes on.

This drove the perception through to today, which is why I write this to clarify some of the misconceptions in the market, and to provide some clarity and surety going forward.

Since approximately 2003 and, officially in 2005, the requirements for compliance with the New Zealand Building Code – E2 (external moisture) changed.

With this we saw the introduction of a verification method for external claddings/facades — E2/VM1 (external moisture/verification method).

Most, if not all suppliers and manufacturers of external claddings/facades, including weatherboard, plaster facade and fibre cement sheet products, have undertaken this testing. It demonstrates the performance of walls with multiple connections such as windows, doors, balustrades and movement joints.

Residential external facade VM1 testing is thorough, and completed in a specialist weathertightness chamber at BRANZ.

One of the tests even involves drilling holes through the finished cladding during the wet testing stage to ensure that not one drop of moisture crosses through the cavity to the structure.

This type of testing with introduced or simulated failure provides confidence that if, during the construction process, something moves, or is introduced post construction, that there is robustness designed within the system that will not impact on the structure or integrity of the building.

These days, many facade products, and certainly all Rockcote & Resene Construction Systems’ cavity-based facades, are tested to prove compliance with the performance requirements of the New Zealand Building Code.

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