Three years before we started this project, we had actually advanced quite a long way down the route of designing an ecological renovation of our existing house, aided by some Japanese architect friends of ours. We wrote a bit earlier on this blog about how we had planned for an extension on the south side that would remedy the lack of light and passive solar heating, and which would also add a second level to the existing single-storey extension. However, problems rapidly started to build up, mainly to do with the quality (of lack of it) of the existing structure, and the fact that whatever we did, it was never going to result in anything like the level of energy-saving performance that we wanted and was going to cost a lot to get even there. So, we abandoned that idea in favour of a new build at a later date.
We scoured the sustainable and green building books. We accumulated massive Bookmark lists from Archdaily and Dwell magazine‘s websites. We looked at a lot of Japanese popular modern architecture and design magazines – which are generally much better than their western equivalents – we bought and borrowed books about self-building, straw-bale, cob houses, ecohouses and more – most of which were very ‘west coast’ American, indeed architecture and design in North America sometimes seems dominated by dreams of ‘the west’.
A fairly typical Earthship
Having helped to build an Earthship before, I was quite keen on trying Mike Reynolds’ design principles out, and we also flirted with the idea of more conventional rammed earth building, but decided that this just wasn’t the right climate for these techniques. And Kayo was less keen on the ‘handcrafted’ look of both earthships and rammed earth. As it happens, there is now an earthship or two and at least two partially rammed earth homes in this part of Ontario, which have been built over the period we’ve been thinking and building, both of which look great. But we felt needed a kind of way of thinking about houses that suited the long, cold winters we have here, as well as the short hot summers and fair amount of rain we have in between, as well as something which had a slightly different aesthetic. For a long time, however, we persisted with the idea of incorporating a living roof into our design, before we decided that this was hardly the biggest priority in a rural area – it might well be a very good thing in cities or suburbs – and that it added a lot of design problems, including weight and limited roof angles.
Aerecura rammed earth demonstration house (Aerecura)
We got to Passive House through the more formal literature on the subject but also through some specific existing examples from the architecture website and blogs, including the now defunct ‘100K House’ blog, and one firm in particular, G.O. Logic, based not so far away from here in Maine, USA. They remain, I think, one of the companies with the best and most cheaply replicable systems of Passive House building in North America, and I’m glad to see they are becoming more successful. We fell in love, for a while, with the clever and colourful simplicity of their prototype Passive House, GO Home, and it’s fair to say that there are elements of our design that retain the influence of that affair. At one point we even considered just buying their plans off the shelf and inquired with them about it.
The GO Home (G.O. Logic)
But then we started to think more about exactly what it was that we wanted out of a new house and the shape and interior structure as well as the materials and concepts like embodied energy. We found we didn’t like the lack of structural shading on the GO Home, and so our roof and porch design is radically different. Rather than having that modern slick look with no overhangs, our roof is unapologetically extended and all about shading the upper storey windows in summer, as well as providing a good year-round angle for solar panels. And the porch shades our lower windows in the same way. As I drew preliminary drawings, I kept finding that it seemed obvious to push more functional elements to the north side and living spaces to the south, and to maximise the passive solar gain, as well as the area of roof space for both solar PV and solar thermal, by a more rectangular shape than the GO Home’s altogether squarer design. Eventually we stopped thinking about the GO Home altogether. But it remains an important influence on our basic thinking. G.O. Logic have, during this period, designed and overseen the building of a number of other passive houses, some of which look more like what we’re doing – we like the Potwine Passive House in particular for the blog that the owner created. Later in the process we discovered the Japanese passive house architect, Miwa Mori of Key Architects, and particularly liked her, again not dissimilar, Karuizawa Passive House. It’s not surprising that people thinking along similar lines would come up with similar ideas, and if you are trying to produce a relatively small passive house without excessive cost, then it makes sense not to stray too far from simple forms. I guess it shows we’re doing some things right.
Karuizawa Passive House (Key Architects)
Of course, we spent a lot of time thinking about, in fact obsessing over, wall construction and insulation, constantly calculating and comparing the U- and R-values of different materials and configurations. We scoured Green Building Advisor and the Building Science Corporation’s site, particular their ‘Designs That Work’ section. We looked at all kinds of heretical ideas that had their evangelists and decided that most of them were well-meaning but just wrong, but we became very familiar with certain building ideas that started on the fringes but which have become accepted as good solutions to high-performing wall units, like Larsen trusses.
However, it seemed that it was difficult to get past the performance-to-cost ratio of polystyrene Structurally Insulated Panels (SIPs). This was a problem, because whole we wanted to do this as cost-effectively as we could, we also wanted this to be an ecological build in more ways than just energy-use once the buidling was completed, and in particular to use materials with as low environmental impact and embodied energy as possible, and polystyrene is a petrochemical product.
When we started working with our architect, Mikaela Hughes of Hughes-Downey here in Kingston, we were initially enthused by the possibilities offered by compressed pre-fabricated compressed straw-bale panels, essentially a kind of eco-SIP (but much, much heavier!). However, when even the company who was making them seemed to start to have their doubts about their own product, we decided we couldn’t go with that, and so, reluctantly we decided that there was no real available substitute for SIPs in Canada for the level of insulation we required. Their website does not appear to be working any more…
Their idea wasn’t fundamentally a bad one and, whatever was lacking in the Ontario firm’s particular execution, others seems to have cracked the problem. If you are in the UK and interested in using straw, a firm there, ModCell, is now producing Passivhaus-certified modular straw-bale panels, which look like an exellent product.
ModCell Core Passivhaus-certified straw-bale panel system (ModCell)
We went back to our wall-designs and came up with a plan for combining some rigid insulation with a Larsen truss wall filled with blown cellulose. It looked a good solutionon paper, so we took it to one of our neighbours here, who works for a blown-cellulose insulation business, and who we were intending to employ on this build. He took one look at the width and depth of the wall cavities and declared that there was no way he could guarantee an even fill in that size of space and make sure that the insulation packed properly around the trusses. And he didn’t think anyone else would be able to do it either, whatever they might promise.
So it seemed like it would have to be SIPs after all. We already had quotes and were ready to order when Mikaela got in touch with the tutor at a Passive House course he had taken, Malcolm Isaacs, of the Canadian Passive House Institute. Purely by coincidence, he had just come back from touring factories in Germany and Austria that manufactured wood-based Passive House components: Cross-Laminated Timber structural elements, and wood fibreboard insulation panels. We had actually looked at CLT, or ‘glulam’ as it tends to be known in Canada, early in the process but the Canadian sites seemed to emphasize building using complicated bent-wood structures. However, the no-nonsense, close-tolerance factory cut systems that were being made in Europe seemed to be just what we were looking for.
A very glamorous CLT house (Stora Enso)
Except they were in Europe. What about the transport? Well, if we could fit everything we needed in a couple of shipping containers, it actually worked out pretty well in both financial and ecological terms (although it didn’t quite work out to be that simple in the end…). But, it did seem odd to be considering importing wood-based products from Europe when Canada has such a large forestry industry. However, the Canadian industry is only just starting to think about these sorts of things at the level of the family home. There is actually simple CLT available, but the quality, at least when we were looking, was not as high, and the sophistication of the factory pre-cutting was more limited (this may now be changing with Guardian Structures, a company based in Ontario, offering factory-cut CLT structural elements). And as for fibreboard, it was only produced in relatively thin sheets. In the Canadian building industry, insulation seems to be something that is still thought of as secondary to pumping out large amounts of heat.
So, that’s how we got to the start…