NELSON BUILDING REPORTS

New insulation standards for Nelson/Tasman May 2023

Recent changes to the New Zealand Building Code have not bothered just tinkering with the insulation requirements for new homes.

They are going to double for the ceiling. Rather than R 3.3, this will be required as R 6.6.

That is quite some insulation depth, 350 mm, more than three times the thickness of the original R 1.9 standard that was originally made compulsory for new houses back in 1979.

It’s hard to change the walls much without increasing the depth of the studs to 140 mm. Wall stay at R 2.0.

Timber floors on piles are another substantial change, going from R 1.3 up to R 2.5.

These new insulation regulations in the Building Code were implemented in May 2023.

You are not compelled to upgrade the accessible insulation in existing homes, but in the long term it is worth considering the new standard when considering a boost in the insulation to an existing home. Many homes with insulation installed in the 1980s or 90s have just R 1.9 in the ceiling.

This suggests a top-up of an R 4.0 blanket is advantageous to keep you cosy, and reduce heating bills in the long term.

That’s about 200 mm extra thickness, although this may need to be reduced in thickness at the edges to allow a minimum 25 mm clearance for ventilation.

From 1 July 2021 all private rentals must comply with the Healthy Homes Standards (HHS) within 90 days of any new or renewed tenancies. These are still the older requirement of R 3.3 for the ceiling, and R 1.3 for subfloor, where accessible.