According to all the most recent research on faults in Class 2 buildings, and the available research on Class 1 buildings, the most common fault and the fault most likely to cause irritation, litigation and contribute to increasing PI premiums is waterproofing failures.
The four areas of most concern are 1) waterproofing at balconies, 2) box gutter failures, 3) cavity wall failures and 4) internal wet area waterproofing. Two issues in particular plague Class 2 apartment buildings; leaks at balconies and internal wet area waterproofing failures.
The reasons for these failures are multifactorial and in consequence the remedies require some careful thought on the part of the design and documentation team.
Two key problems are:
1. National Construction Code (NCC) is a minimum standard only. It is not intended as a guide to good practice, or even adequate practice, and designers and documenters need to understand that slavishly following the recommendations in the Code and the Australian Standards it calls up are potentially a recipe for failure.
Developers and developer builders are often tempted to design down to the standard rather than provide a durable solution.
2. On site miscommunication/misunderstanding - Subcontractors are unable to interpret documentation, do not know the Australian Standards they are being asked to apply and have insufficient knowledge of the behaviour of the materials they are using. The builder and the subcontractor cannot effectively deliver a durable waterproof detail if they cannot follow the documents, and this is likely to be the cause of disputes.
Mecca is presenting two CPD Webinars next month that have been designed to address waterproofing problems and close the gap between design intentions and on-site delivery of the project.
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