Home Forums General Discussion Underfloor insulation mandatory? Reply To: Underfloor insulation mandatory?

Gleb Speranski

Hi Ian,

Thanks for your reply. The issue with the Code is not so much in insufficient levels of thermal efficiency required (even though that is important as well) but in the fact that the Code offers absolutely NO means to validate whether those levels are actually achieved.
Insulation gets ticked off by council’ inspectors visually- mainly based on the fact that it is present (installed). How well it was fitted and, subsequently, how well it is going to work is NOT being checked. There are some more vigilant inspectors who are trying their best but even they don’t have a guidance document to work against. NZS 4246 for installation of insulation is not recognised in the Code as the compliance document and NZS 3604 does not even mention insulation even though that one is a builder’s Bible.
In our research we evidenced very poor thermal performance in new builds- in a brand new home with R2.6 insulation in walls, the in situ performance of the entire wall was R1.3.
It is never one problem only: in my experience it is a combination of things- poor thermal design, products not being fit for purpose and, of course, installation.
So, here we are having ‘performance’ requirements that are insufficient on one hand and often not achievable on the other.
After walking streets of Christchurch in August I was horrified to see that energy efficiency does not even feature in new houses being built around Wigram. It looks like the opportunity to improve the housing stock in the city is being wasted which is a real shame.
I recently presented a paper on the issue of insulation in new builds at the Building Better New Zealand conference in Auckland.