In an ideal world, we would live in homes that promoted our overall family health and had no impact on our surroundings. Unfortunately, the truth is less rosy. Green construction techniques and materials are more available than ever before, but that still translates to homeowners seeking out viable alternatives and being informed about the tortuous route taken by many products.
In North America, climate is a major consideration for building choices. Whether extreme cold, extreme heat (or both), torrential rain, humidity, desert conditions, or tornados – this continent boasts most possibilities. And that means adapting standards to suit the place. But one component is consistent – homes need insulation.
Insulation is provided by a wide range of materials – from mineral fibres, pellets, and aluminum foil to polyurethane foam. The type of insulation is determined by climate and location in the home. Roughly 50-70% of domestic power use is heating and cooling houses. Older homes use more energy than newer homes, and even recently constructed homes benefit from insulation. These materials prevent heat loss in winter and heat gain in summer. The degree of resistance to heat flow is designated as the R-value. Insulation also acts as a sound absorber, reducing noise from outside – or diminishing your jam session’s effect on the neighbours. Common areas to insulate include attic spaces, ducts, exterior walls, and foundations. Any area exposed to both the exterior and interior of a home could benefit from insulation.
Fibreglass is a spun glass product, often derived from recycled glass, used since the 1930s and one of the most common insulations. Its main drawback is irritation of the skin, eyes, nose, and throat from airborne fibres, and possible carcinogenic properties of these fibres. Mineral wool is non-combustible fibres made from glass, stone, or slag. About 98% of the components come from rock or slag set in a resin. Thermal properties make this material appropriate for ceiling tiles, pipe insulation, and other applications. Asbestos is one form, but health concerns around this mineral have abated somewhat. It is probably a greener option.
Foam, including polystyrene beads, polyisocyanurate, and polyurethane is also widely used. Fibreglass and foam products have higher R-values. However, lingering concerns persist about the production and sustainability of petroleum by-products, as well as off-gassing, and the use of hydrochlorofluorocarbons in manufacture. Some forms of insulation are also treated with flame-retardant chemicals, offering an additional concern.
Vermiculite, from a mica-like mineral, is another possibility, but asbestos fibres have been found in older ore dating before the mid-1980s. Perlite, a naturally occurring volcanic glass, is poured in loose pellets. Cementitious foam, derived from seawater minerals, is a useful alternative to polyurethane foam and also boasts being nonflammable. Another green possibility is straw core, which has seen a revival after many years out of favour. Like some of the other natural fibres – cotton, wool, and hemp – the R-value is lower. This issue is tempered by the environmentally friendly factor, although it is hard to imagine sufficient wool or cotton to insulate every home. Add in the existing pressure on these products to be more ecologically sound and pesticide free.
One Canadian group, Parkland Industrial Hemp Grower Co-op, has come up with an alternative. Raw hemp and flax hulls are processed into a fibrous material that both provides insulation and reduces waste, offering another alternative to fibreglass. Hemp and flax residues are of low value and present problems for farm equipment, so this recycling will be beneficial for all involved. It also promises a new renewable source for insulation.
