Insulation: keeping us cosy and cool

Eleven weeks into the build and one of the key components that will make our home a high performing energy efficient house arrived on site, and is now being incorporated into the structure.

Three trucks delivered 150 cubic metres of Pavatex, a wood fibre product that will provide two layers of insulation. Insulation is one of the five pillars of passive house building design. In winter it is our house’s fleece and in summer it’s our esky (or chilly bin if you’re Kiwi).

There’s not a lot of storage space on the postage stamp.

The passive house plan created by our passive house expert specifies the required R-value (thermal resistance) for insulation based on our house’s location and climate. We’ve chosen to achieve this R-value with two types of Pavatex wood fibre product supplied in Australia by Life Panels.
The first layer to go on is compressed wood fibre board called combi-board which is added to the external side (including roof) of the frame. It’s looking good and becoming quite a conversation starter for passers by. Not only is the product not common in Australia (as it’s from Switzerland), but it’s also not common to put this layer of insulation on a home in Australia.

Combi board on the walls
Combi board on the roof

The next layer is the bulk infill layer. This layer is similar to insulation batts used in in roofs (and increasingly so in walls in Australia), but made of a very different and much nicer material that have better thermal and structural (ie don’t sag over time) properties than standard batts.

Bulk infill ready to go

The wood fibre products report to perform very well thermally and acoustically. The builders tell us it’s easy and good to use. We’re already noticing it softening the traffic noise

Snug layer of wood fibre all around the house

Not only are the wood fibre products ticking the thermal boxes for us, we also like them because they are made using wood off cuts (reducing waste), are carbon sinks and help contribute to a healthy indoor air quality as they don’t off-gas volatile organic compounds (VOCs). Winning all round. We’re looking forward to it keeping us cosy and cool and reducing our energy costs.
Next step: Gortex wrap!

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