Home Forums General Discussion Building permits for insulating walls. Reply To: Building permits for insulating walls.

Gleb Speranski

Hi All,

The only determination that I know of was issued by DBH back in 2011. Wall insulation retrofit guidance is available at this link … http://www.dbh.govt.nz/UserFiles/File/Publications/Building/Guidance-information/pdf/retrofitting-insulation-in-external-walls-guidance.pdf

In the nutshell, the document explains that while building work associated with the wall insulation retrofit must conform to the Code, insulation products installed do not have to meet H1:

The Building Code performance criteria listed below are the relevant provisions of the Code to consider when assessing retrofitted wall insulation and whether it complies with the Code. Other Building Code performance criteria may also need to be considered for the building work associated with retrofitting insulation. For example, removing and reinstating structural wall linings or drilling holes through studs would require compliance with the Building Code clause B1.3.1. However the insulation itself does not need to comply with B1.3.1 as it is not part of the structural system of a building.

It is useful to highlight upfront that the R-value of the retrofitted wall does not need to comply with the Building Code clause H1 Energy efficiency. There is no doubt that insulation is retrofitted to improve the wall R-value, but from a regulatory point of view retrofitting insulation is simply an alteration of the ‘thermal envelope’ described in H1.3.1(a). Unless the cladding, framing and linings of the wall are also reconstructed it is hard to consider how the ‘thermal envelope’ has been reconstructed, which would trigger compliance with H1.3.1(a). Therefore, the energy efficiency provisions of the Building Code are not mentioned in this section, which lists the performance criteria that insulation retrofits must comply with.

I was not aware of the MBIE determination and would like to find out more about it. Can you please provide a link to it?

Kind regards,