DIY

Changes to the Rental Tenancy Act introduced in July 2016 state that all rental properties with crawl space access to the under floors require installation of adequate insulation. Research has found that underfloor insulation without a wind-wash barrier can lose up to 25 per cent* of its thermal performance on blustery days. We recommend you look for insulation with a wind wash barrier to ensure the insulation’s thermal performance will not be affected.

What insulation do I need to comply?
Insulation levels can vary depending on the zone that your property is located. It is also important to ensure that the underfloor insulation you use is NZS 4246 compliant, which means using a product that has been designed to perform in under floors without a fully enclosed perimeter. Earthwool glasswool: Underfloor roll with a wind wash barrier has been specifically designed for windy conditions and will perform as it should. To see which underfloor product will be suitable for your property, check the tables below.

Once you have selected the product you need you can:

  • Calculate the number of packs you will need.
  • Watch our handy install video to see how quick and easy it is to install Earthwool® glasswool insulation.
  • Purchase your insulation from your local Bunnings store.
Click your zone for recommended insulation products



Our recommendations for insulating with glasswool insulation:

North Island (Zone 1 & Zone 2)

Underfloor Insulation
Thickness of existing insulation* R-Value (m2K/W)
0mm R 1.8 Underfloor roll with wind wash barrier
Insulation must be installed to meet standard NZS4246

South Island & Central Plateau (Zone 3)

Underfloor Insulation
Thickness of existing insulation* R-Value (m2K/W)
0mm R 1.8 Underfloor roll with wind wash barrier
Insulation must be installed to meet standard NZS4246

When you are ready to install Earthwool glasswool read our install instructions here before you start

*Build 153. April/May 2016