Cue up the jokes about huffing and puffing, there have been so many since these seven houses were put up for sale in Shirehampton, a suburb of Bristol. Straw bale is usually the preserve of self-builders (the British term for DIY homebuilders). These houses look pretty much like all the other boring brick houses in the district, but are much more energy efficient and quiet inside. And as Matt Hickman notes at MNN, "It would take an extraordinary force of nature to blow one of these straw-stuffed brick abodes down."
That's because they are not strictly straw bale houses in the traditional sense, but something much more interesting. They are in fact built with Modcell's prefabricated panels, which are sixteen inch deep timber framed panels which are insulated with straw. This is not just semantics; it is what makes Modcell such an interesting concept that can be used for any kind of building, and in multi-story designs like these houses. I don't think they should strictly be called straw bale at all; it is really a cross-laminated timber house clad in brick that happens to be insulated with straw.
The Modcell system combines the strength and stability of a timber structure with the insulating ability of straw, which is considerable. Straw is also totally renewable, a waste product, and cheap. And as one can see in this photo, these really are prefab wood panels with the straw just as infill. This will give comfort to anyone worried about a wolf huffing and puffing, although in the fairy tale the wolf did blow down the house made of sticks too. Perhaps that's why this developer clad the houses in brick; they certainly didn't have to with the Modcell system.
Peter Walker of the University of Bath tells the Guardian that the stuff really performs.
Over the past three years of research we have looked at various aspects of the performance of straw. Two that particularly come to mind as concerns or apprehension from potential users of straw are fire-resistance and weather-resistance. We have conducted a number of fire tests that have demonstrated that fire resistance from straw bale construction is remarkably good and better than many contemporary forms of construction. In terms of durability, we have undertaken laboratory tests and undertaken monitoring of existing buildings and we have also done accelerated weather tests. The results of all these tests suggest that straw is a very durable construction solution.
The Bristol project is notable because it is the first time that Modcell has been used for spec-built housing in the open market, but an earlier project is far more interesting: the LILAC affordable ecological co-housing.
LILAC means Low Impact Living Affordable Community. It is a member-led, not-for-profit Cooperative Society registered with Financial Services Authority. They are building a community of twenty beautiful homes in Bramley, west Leeds on an old school site. Their community will include a mix of one and two bed flats and three and four bed houses. Most will have private gardens, and the upper flats will have balconies. The homes will be self contained with kitchens, bathrooms and living space, and finished to a very high standard. A common house will form the heart of the community, offering shared facilities.
There is so much to like about Modcell, beside just the straw. It doesn't get any more local; in an earlier Modcell project we have shown, a high-tech demountable modular café, they actually grew the straw on site and built the panels in a "flying factory" set up nearby. It is carbon negative and can achieve passivhaus standards. It really doesn't get any greener. More at Modcell.