Blown insulation systems making a comeback


By Safe-R Insulation (NZ) Ltd general manager Wade Maurice

We all know that the majority of New Zealand’s ageing housing stock is not adequately insulated, and while an effort is being made to retrofit ceilings and floors, the absence of wall insulation dramatically reduces the benefit of this effort.


The key to good thermal performance is a completed thermal envelope — and without adequate wall insulation this is not attainable.


A variety of wall insulation systems have been retrofitted to New Zealand homes. Traditionally these were installed by small-scale operators with limited technical capabilities using products such as blown cellulose or sheep’s wool.


The absence of regulated installation systems and quality moisture repellent materials put off most consumers, which resulted in very few homes being retrofitted using these techniques.


Expanding wet foam systems, installed via small holes in the linings, gained popularity during the 2000s, but clarification on the requirement for building consents, coupled with bad publicity (mainly focused on the shrinkage of the foam), reduced the popularity of this system.


The good news is there are new alternatives to removing the linings or cladding when retrofitting wall insulation. Blown insulation systems are again making retrofitted wall insulation viable, and there are a number of solutions available.


Those considering retrofitting wall insulation should realise that it is important to choose a company that uses an audited system.


This should include assessment of the building to ensure it is suitable, and that the product shouldn’t introduce moisture to the cavity during installation. It should feature some form of water repellency, a proven cladding reinstatement method and documentation showing compliance with the New Zealand Building Code.


The installation of all wall insulation requires a building consent, but exemptions may apply to systems in some areas. A reputable company can help you through this process and ensure you get a great result from the new retrofitted wall insulation.

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