CosyWall Blow-in insulation - FAQs

Installing insulation into existing walls of homes - your questions answered.

Existing Homes - typical Questions

Research shows that 30% of heat loss occurs through your walls.  If you have already installed ceiling and underfloor – think of it like a tomato sandwich – the heat is going to squeeze right out the walls like a sliced tomato!

The glasswool insulation we use exclusively for our system is Supafil® – made from recycled glass and sand.  In addition, the product is silicone treated to provide the required performance and enhanced durability.

The insulation is manufactured in selected plants by melting and spinning a blend of inert, natural minerals. It is non-combustible, water-resistant, breathable, won’t settle or shrink and has a trouble-free history of insulating New Zealand external wall cavities since 2002. CosyWall™ is packed in plastic weather tight

Supafil® is non-combustible

Yes, CosyWall provides BOTH acoustic and Thermal performance.

Where installed, CosyWall delivers high R-values in comparison to other exterior wall insulation types

R2.8 for Weatherboard >1950 with nogs. (Deduct R0.2 if Sheet
R2.9 for Weatherboard <1950 510c/c, no horizontal nogs
R3.9 for Brick with 40mm cavity, no building paper

See the CosyWall Datasheet for more detail

CosyWall is a dry glasswool, unlike other expanding foam type systems that is injected wet.  Also no risk of potential noxious fumes.


CodeMark is an unchallengeable form of product assurance.

Building consent authorities (BCAs, usually councils) must accept a product certificate as evidence of compliance with the Building Code.

CodeMark is the only deemed to comply product certification scheme in Aotearoa New Zealand that shows a building product or method meets the requirements of the Building Code.

How Enstall do it - weatherboard/direct fix homes

Yes, based on the design and condition of your house, we can install CosyWall into most house types.

See the CosyWall Datasheet for all details

R2.8 (90mm) is well above the minimum R-Value for new houses constructed in Auckland.

Enstall’s preference is to install from the inside.

How Enstall do it - brick veneer homes

Yes, based on the design and condition of the house we can fill the wooden frame together with the additional cavity

See the CosyWall Datasheet for an explanantion of the R-Values

We install from the inside and outside.

We apply a Masonry Protection Barrier to the outside faced of untreated bricks designed to prevent liquid water penetrating the brick.

For houses with brick veneer external cladding we will also need to ensure that the outside face of the brick is sealed as most brick systems are porous.  To achieve this, we will need to check the specific condition of the brick work and we will need to apply a specific sealant to the brick work.  Our quotation will outline what needs to be done to ensure effectiveness of the sealing system, and once installed the maintenance required to ensure that seal continues to perform.

Other important information

. CosyWall™ usually requires BCA consent. A building risk assessment is undertaken for each site prior to consent application. Upon work completion licensed installers must provide site records to the BCA and state the installed thickness

We offer you the choice of patching the holes using a patented system resulting in an almost good as new finish.  This can also be colour matched to existing paint as well.  Let us know at time of quotation what you require.

Yes, our installers and assessors are trained and confirmed as being competent to ensure all steps in our processes meet the CodeMark requirements.

A typical New Zealand three-bedroom home (weatherboard or brick veneer) can be insulated in less than a day by an accredited installer team. It’s quick, clean and doesn’t affect the structure or look of your house.