Construction has been slow over the last couple of weeks; getting the roof done last month was huge (and exhausting) so we took a breather, and now we are waiting for our glazing system to arrive from New York state before we really get serious with the front wall.  All this time off has allowed me too much time for reflection …

Completion of the roof and planning the glazing for the front wall have left me feeling slightly conflicted.

Our roof is a testament to modern construction practices.  The EPDM roofing membrane (think inner tube rubber) is amazing; it has a long service life (over fifty years in many cases), and it simply does not degrade.  It has also left me feeling like I literally poured oil on my roof by the barrel.  EPDM is a petroleum product … it is literally a sheet of plasticized oil.  Also,  as I discussed earlier we are now going to use an extruded aluminum glazing system for the front wall which will hopefully reduce moisture concerns with the sloped greenhouse wall.  Aluminum is an incredibly energy and resource intensive material to manufacture, not to mention we are shipping it from thousands of miles away.

Don’t get me wrong … I am pleased with our roof  and excited about the front wall.  But do these products belong in a sustainable house?  I suppose it depends who you talk to …

When we first started thinking about this project we looked at different green building standards and if they would be applicable to our building project.  The LEEDS standard is probably the best known, but we did not see how it applied to our project and were frankly not impressed with it.  The LEEDS system works with the existing building code and seeks to make existing construction practices more ‘green’.  I think we need to completely re-think many of our existing practices, hence my infatuation with earthships … LEEDS simply does not go far enough for me.  Recently, I have read about a much more radical implementation of a green building standard called The Living Building Challenge implemented by the Cascadia Green Building Council.

The Living Building Challenge definitely forces you to re-think building practices and strives to reduce the embodied energy in a building.  I believe this standard has the right idea, although I think it is too rigid in some respects.  As an example, using wood to heat domestic hot water or supplement the heat in a home is discouraged in favor of passive solar heating.  Where I live (British Columbia) we have a lot of wood, and limited solar gain in the winter months due to cloud cover.   Residual fibre from logging and milling operations is burned as a waste product.  In this case it seems to me we should be encouraging better resource utilization in addition to passive options.  Regardless, Ann and Gord Baird have built a beautiful cob house that is in the running to become one of the first buildings recognized by this challenge.

I am not sure what specifically either of these standards would have to say about our building.  But to this point in our project I have felt very positive about the green-ness/sustainability of our choices; we have re-purposed material for our walls (tires and cans), built with available resources (the wood for our project has all been recovered from our site and we are using the wool from our sheep and the dirt from our site in our cob mixture), and the labour has been locally sourced (mostly it has been us!).  Granted, we have purchased many construction materials to move this project forward (portland cement, screws, electrical wire …), but we have mostly built with materials available to us.

The materials used in the roof and greenhouse wall are not ‘sustainable’ products; they were purpose made for this project, lots of energy and resources were used to manufacture them and they were shipped a long way to get here.  Ultimately, I accept using these products in this building for the longevity (hopefully) they will provide.  The extruded aluminum system on the front wall means that I will not have to replace rotten wood in ten years, which ultimately reduces the maintenance costs (energy, materials and money).  Despite my concerns this seems to be an acceptable trade-off and for me justifies using some questionable materials.

the following paragraph from the Forward to Local Sustainable Homes by Chris Bird (the forward is written by Rob Hopkins) sums up my view nicely,

… housing ourselves can be, and needs to be, about far more than simply having a roof over our heads. The model today is one of homes designed for us, built from high-embodied-energy materials, with a high carbon footprint; materials sourced wherever in the world they can be found cheapest; and the property purchased in a way that saddles us with a debt we then spend many years struggling to pay off. How would it be if, instead, we were more involved with our homes’ design, if our choice of materials meant that it became possible for local businesses to emerge to provide them, if the construction process worked in such a way that people could be trained to engage with construction for the first time, and if the homes were built in such a way as to require no space heating at all? We could, by building ’sustainable homes’, produce buildings that lock up more carbon than they produce, that have a local distinctiveness, and that stimulate the local economy rather than leaching from it.

I would have felt better about both the roof and the greenhouse wall had we been able to source these products locally.  I am a strong believer that economic localization encourages sustainability, and we have found ourselves moving more and more in that direction.  However, there is also the simple reality of our economy.  Globalization has discouraged local business and local expertise to the point that it is increasingly hard to find the materials or the skills locally.  In both of these cases I was unable to find these materials locally no matter my preferences.

Scott Adams, the author of the cartoon strip Dilbert, recently wrote a hilarious article for the Wall Street Journal on his experience building a green house.  Like most things that make us laugh it poked fun at the reality of an ‘ideal’ experience (in this case trying to build a sustainable house).   In his words,

… The greenest home is the one you don’t build. If you really want to save the Earth, move in with another family and share a house that’s already built. Better yet, live in the forest and eat whatever the squirrels don’t want. Don’t brag to me about riding your bicycle to work; a lot of energy went into building that bicycle. Stop being a hypocrite like me.

Like I said, it depends who you talk to …