The choice of materials in the home will have a significant impact on reaching a number of the project goals - low embodied energy, health, comfort, and reduced pollutant emissions both within the home and the wider environment.
Materials that are the highest performers against these criteria can have poorer structural or thermal performance, and be less durable. It is therefore important to take a long-term view and consider materials based on a life-cycle analysis. For example, if a product needs to be replaced every 10 years this may be more energy-intensive than using a product with higher embodied energy that will last 100+ years.
Throughout design and construction we've thought very carefully about four key aspects of each product that has gone into the house:
- The type and volume of raw materials used in manufacturing,
- The effects on health while products are installed and located within the building,
- The durability of materials so resources aren’t wasted in unnecessary maintenance and replacement, and
- The recyclability or safe disposal of products once they’ve reached the end of their use.
Minimising toxicity on-site has positive health impacts for both the builders during construction, and us after we've moved into the home. Two of the most visible examples of products that were chosen with this in mind were the low-VOC paints throughout the house and the non-treated cladding that is used on that exterior and within the entranceway and garage.
While these are two of the most visible materials in the home, within the walls we've also used products that minimise toxicity. We've installed non-PVC cabling throughout the house, and for the pipework have used polypropylene pipes for water supply and polyethylene pipes for water waste. The GreenStuf insulation is also bonded using heat instead of chemicals.
This is a lifestyle choice for us. We want to reduce our impact on the planet as much as we can, and we’re fortunate in New Zealand that there are products available for every aspect of a house’s construction that make it possible to do so.
The challenge, however, is in finding those products. We had to do a lot of our own research to discover what materials were in different products on the market. We believe there's a huge opportunity for companies who are supplying environmentally-conscious products to make this level of information available and accessible to those consumers who are wanting to make informed decisions.