Tuesday, January 09, 2007

A sustainable eco-friendly house?

Building a house is by nature not very eco-friendly. Alot of new materials are required and the land is left scarred after all the excavation and site works. A pile of waste is created as well.
At one stage I looked longingly at strawbale or mudbrick building as a way of counteracting the huge level of consumption required in conventional building but Greg couldn't be convinced.
So within the confines of normal materials we really strived to build a house that has as small an impact as possible on the environment. Have we succeeded? Not as well as I would have liked.

Positive things:
  • No poisonous termite chemicals required ever due to the off the ground steel frame.
  • Small footprint ( 8mt x 12mt) means more land can be planted and less roofing materials are required to cover our living space because we went 2 storeys high.
  • Solar hot water should reduce our coal burning power consumption by around 30%.
  • Large water tank means we are self sufficient in water.
  • UV treated waste water means no chlorine or concentrated nutrient loads will ever leach into the soil and build up - and water is re-used on the garden.
  • Very energy efficient design means we'll use less power to heat and cool. Large eaves, minimal windows facing west, north facing verandah, low thermal mass roof and walls, high R value insulation & under floor ventilation all contribute to a design that suits the wet & humid, hot in summer, cool in winter climate of the subtropical rainforest.

Negative things:

  • We weren't able to use recycled windows due to the government requirement that a glazing certificate be provided ensuring adherence to Australian Standards - bugger!
  • Steel has a high embodied energy so was and 'environmentally expensive' choice - the trade off was that we have a termite barrier without toxic chemicals.
  • Clearing the block removed habitat for native animals & birds - we hope to replant and rectify this as much as we can.
  • Our decking (merbau) and framing (cypress) both come from non-sustainable forestry sources. The only thing I can say is that we will be living here for many years and caring for the timber so it never needs to be replaced but I really feel rotten about this point.

In the future, we hope to make our property more sustainable through the following:

  • Keep chickens (to be fed on kitchen scraps and other green waste)
  • Grow large amounts of our own vegies and fruit (and eggs of course)
  • Grow habitat for birds, native mammals and beneficial insects
  • Addition of grid connected solar power to supply all our power needs

Of course, we still have a house to build so I'd better go and help Greg with the tie-down rods!