The perfect wooden Passive House

Just when we thought we had everything worked out as well as we could and were happy enough, we got news of a completely different way of building the house that instead of being just ‘good enough’ would be perfect.

We had a project-transforming meeting with Malcolm Isaacs, one of the founders of the Canadian Passive House Insitute, and who taught the passive house course taken by our architect, Mikaela Hughes. Malcolm has just started to work with some manufacturers in Germany and Austria, who make factory-built wooden passive house components (walls, roofs, windows etc.). These are built to far higher specifications that anything it’s possible to find in Canada, and they come from sustainable sources.

The structure, including all external and internal walls, floors, ceilings, roof etc. will be entirely Merk Leno Cross-Laminated Timber (CLT), just about the strongest form of timber there is. The external structure will be clad in Schneiderholz wood fibreboard insulation. All of this comes cut to the millimetre in the factory in Austria and sent over by sea in shipping containers. It should take about 2 months from order to delivery, which gets us into September, way too late to start building, right? But the trick is that once it gets here, the components should take no more than 2 or 3 days to put together with a crane and a whole lot of long screws, rather like giant Ikea furniture!

Merk Leno CLT Panels being lifted into place

Add a water-resistant but breathable, layer – absolutely no ‘vapour barrier’ which would obstruct the natural qualities of the wood – and some kind of rainscreen cladding – we will use local white cedar – and a basic steel roof, and that’s pretty much it for the structure.

A finished Merk Leno CLT-built office building

This is all good, but not only is this going to be as highly-insulated as our previous plans, but it will be a lot more tightly sealed, with far better finishing, far higher quality windows (about which more in a future post) and… believe it or not… cheaper than the stick-frame and SIPs combination we had almost settled on before. The lower price is due to several things, mainly the fact that there will be no framing or trusses, and hardly any dry-walling or painting and other finishing, but also the fact that the manufacturers concerned are looking to expand into North America, and we are one of the first willing test subjects.

So right now, Mikaela is hard a work redrawing the plans a little to accomodate this pretty fundamental change (which isn’t the only one, but I’ll write more about that later this week!). But there’s a big question here: why isn’t there a Canadian company that can do this? You would think that with Canada’s forestry industry needing new ideas, the cold climate, and the massive home-building market here, that a made-to-measure wooden passive house company would clean up. It seems to me that most houses will (or should) be built this way in 30 years. There are Canadian producers of CLT, however most is vastly inferior to that produced in Europe and what’s more they simply don’t have the facilities to custom cut in the same way. And no-one produces wood-fibre insulation. Canada is still dominated by the belief in cheap fossil fuels and the idea of infinitely expandable land and resources. There are so many reasons why this has to change, but it isn’t changing very fast…

6 thoughts on “The perfect wooden Passive House

  1. Pingback: Heating a passive house… the other last minute design change. | Wolfe Island Passive House Project

  2. Pingback: Plans and Exterior Elevations | Wolfe Island Passive House Project

  3. Pingback: How We Got Started | Wolfe Island Passive House Project

  4. ethan

    Hello! I’m interested in your assertino that CLT and fiberboard was going to be “… believe it or not… cheaper than the stick-frame and SIPs combination we had almost settled on before.” Do you have any way to tell if this cost savings has come to fruition?


  5. Pingback: Reflections After a Year of Living in Our Passive House | Wolfe Island Passive House Project

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