I enjoyed reading the June 20 article by Ian Goudie (Natural Vs. Green Building) as I have made my living for the past 12 years in the field of green and natural building, but I wanted to follow up on a few points. The article is well intentioned and I do agree with some points, but if the goal is to help create more green homes built with natural materials there are some points that need to be corrected.
I agree that not all buildings that are “natural” are green and vice versa. For instance, a log home would not be a green building as they are poorly insulated, leaky, and take a considerable amount of energy to heat. Even if the log home is heated with some passive heat and with wood the shear volume of energy wasted by inefficient construction (lacking insulation, air sealing and heat recovery) will in general ensure it is not a green home. It could make a fine cabin but not a year-round home if using less energy is a goal.
That said, there are good examples of approaches to green buildings that are made of wood, with wood vapor barriers. One good example is the Passive House standard, which has over 20,000 homes completed with one was just completed in Nova Scotia. Passive Houses use 90 per cent less energy for heat than a new house built to code in Newfoundland. One Canadian made wood based prefabricated system (which I believe most would consider to be natural) can be seen here.
Going beyond just energy the Living Future Institute has a world leading certification called the Living Building Challenge — the resulting buildings produce as much energy as they consume, harvest as much water as they need, use healthier materials and result in buildings that contribute to the surrounding environment. There is even the requirement to avoid toxic products that endanger human health — these items are on the “red list”.
I would argue we don’t need to go back to poorly performing insulations in order to build natural homes. Rock wool is one great naturally derived insulation, being made in Canada from Basalt and in many cases with 50-75 per cent recycled content. Cellulose (recycled newsprint with some borate as a preservative) is another great option. While you can’t buy sawdust to insulate your house, you would not want to. You can however buy cellulose and rock wool, both of which are natural and insulate four times better. This lowers energy use, increases comfort, and lowers monthly costs which increases affordability.
The author talks about vapor barriers and likely he is referring to polyethylene, which is a plastic commonly used as both a vapor and air barrier. In a house or climate with air conditioning, I agree you do not want to use a poly air barrier. That said, an air and vapor barrier are needed to make a long-lasting energy efficient home and there are lots of great alternatives to basic poly.
The author mentions that mold can be an issue with vapor barriers (I prefer the term vapor retarders which is more precise) in the summer. If a house has air conditioning then a poly vapor barrier is not a good idea, but there are many vapor barrier options that will work well even with A/C. As most homes in Newfoundland do not have air conditioning a poly air and vapor barrier is a fine choice, although there are non plastic alternatives if desired.
The author mentions not needing a vapor barrier or insulation in a log home. In a Canadian climate you can’t build a year round home without insulation and have it be anything remotely energy efficient, green or in sync with nature.
A good local resource is the folks at ThermalWise, as they have a St. Johns office.
The house highlighted in the article may be able to keep itself warm on a sunny day but the test of a house is its performance in a Canadian winter. A passive house will perform much better and there are many modern resources to help those interested to build low energy homes, and while resources from the 1970s may be of some use there is a considerable amount of modern knowledge that can be useful in building low energy, natural, deep green homes in Canada.
Chris Higgins / Vancouver, B.C.