Choosing the best building materials -Resources (Education)- E

Solar Home Chronicles 11

Tuesday, 23 October 2007

This may be the most difficult aspect of designing and building our solar home. Our goals are not just to save on electricity bills in our own home _ we also want our project and lifestyle to more closely fit with broader issues of sustainability. When we start to link some of our personal choices with regional and global issues (such as global warming, over-use of fossil fuels, clear-cutting of diverse forests, air pollution generated by the production of complex materials, etc.) our decision-making suddenly becomes quite complicated.

One of the first things that Eric and I try to do in all aspects of our lifestyle is to buy locally. This not only supports our local economy, it also cuts down on the burning of fossil fuels in the transportation of the goods to our home. As well, when we know where something comes from and how it was produced, we will know whether or not we are fairly compensating someone for their labour and resources. In our quest for building materials, buying close to home is a main goal.

The use of highly-processed building materials raises a number of questions for us. Whenever something is highly-processed, then there has been an amount of electricity or fuel burned during production. The product itself may contribute to my saving of energy (e.g. there are some great new insulating products with complicated chemical names, that you know must have been highly processed both chemically and physically), but do I want to encourage the expense of energy and potential increase in pollution (a by-product of processing) by buying them? Unfortunately, I am unable to find the kind of information that compares my savings with the potential negatives of production, so we are having to make these decisions out of gut instincts.

Another issue with highly-processed products is that they are often made with chemicals that eventually gas-off into the environment. These volatile organic compounds (VOC’s) are the stuff that many people are developing environmental illnesses, or `sick building syndrome’, from. Our bodies have a capacity to deal with small amounts of these chemicals, through detoxification by the liver, but when we saturate our liver enzymes (through over-exposure), then the chemicals build up in our bodies and make us sick. Once people develop environmental illnesses, they become very sensitive, and even small amounts of chemicals can trigger illness. This can be quite debilitating.

There are now many building materials available that are natural products, with very low levels of VOC’s. As expected, the more natural the product (e.g. plain wood), the healthier the building.

Unfortunately, one of the building materials that is key to our solar home is a highly-processed foam insulation _ extruded polystyrene. This is the insulation material that will be placed between our concrete slab floor and the ground, so that the cold from the earth will not seep into our home during the winter. Extruded polystyrene is a very good insulator, and has another important quality _ unlike Styrofoam, it does not soak up water (moisture can compromise insulating products). Apparently, we have no other options than to use extruded polystyrene for this purpose.

Extruded polystyrene is not made in our region (so much for encouraging the local economy), it uses energy and chemicals in its production, and The National Library of Medicine in the USA lists its acute hazard as respiratory and eye illnesses from the dust generated when you cut it, and hazardous vapours if it burns. I don’t suppose we could avoid cutting this, could we…?

So, we already know that we will have to sacrifice some of our ideals as we build our home. And I’m sure that this balancing of the negative and the positive will continue right down to our final choices of paints and other finishes.

Next time, I will tell you a bit about the choices we have made regarding wood.