Continuous insulation, what the heck is that?

We will explore what is continuous insulation, why is it even different to our current insulation standard. why is not that popular in Australia yet.

The Monk

7/5/20242 min read

It's definitely foreign here in Australia residential building industry. It is a common building practice is severed European countries, USA & Canada.

The "Foam board" section that sits between the frames and the exterior veneer is the Rigid insulation. This diagram is from youhome.gov.au - where the Australian government documents higher standards of insulation - compared to what they can convince the industry to adopt.

The fact the foam board resides outside the timber frame makes it an exterior insulation.

In this second picture, such an exterior insulation is shown wrap the entire conditioned living area - like a down jacket pretty much. This ability to continuously encompass the entire living area - reduces the thermal bridges and enables the effectiveness of the insulation.

This is in contrary to placing only Batts between the timber frames.

Why is my builder not talking about it?

Status quo standards: Providing the traditional insulation using Batts between your frames satisfies the expectation of 7-star rating is part of the Nationwide House Energy Rating Scheme. Doing anything more than that lacks the motivation for an oridinary builder.

Trade limitations: Adopting something new requires familiarity with the trade. In the current labor market the trades are already thinly stretched and earn well without having to learn or try anything new. Unless there is a signifiant need, there willingness to learn in questionable.

Let understand some other parameters that impact the rationale,

  1. Cost of building - is a builders concern as much as your concern, they will want to keep the cost low for a competitiveness and attract customers - they don't have to go beyond what the market needs.

  2. Energy efficiency savings -- Long term cost savings due to energy efficiency is something the builders are not incentivised to think about. This is beyond what a builder cares about. This has be driven by the consumer, owner and regulator.

  3. Energy usage Impact on climate change - Again something the consumer and the regular's concern. Not the builders problem.

  4. Improved thermal comfort of home - Exterior continuous insulation greatly enhances the thermal comfort of home. But it is the owner and the consumer that care about it -- not the builder, they are not going to live in it.

  5. Durability and moisture management -- There is an element of pride that a builder can associate with this aspect. Quality builders build durable houses. Moisture management is a key element of the durability in light frames. But the enhanced durability and the moisture management on their own do not provide enough incentive to the builder to rally for it.

  6. High long term property value -- One more parameter that doesn't incentivise builder but only an concern for the owner.

So overall, unfortunately, the incentives for the builder and trade to adopt this model has to be largely driven by consumer awareness and improved regulatory standards and policies.

conclusion: In the current state, your builder is not going to talk about, you have ask for what is good for your home.
But.. a big but.. this can't last for long, Australia's building regulations are catching up and it's only a matter of time.