Insulation is a very important feature of sustainable buildings. Good insulation reduces the need to use energy for both heating and cooling. Combined with passive solar design, insulation can mean you avoid using an air conditioner at all on 40 degree Celsius days.

Insulation can be retrofitted to existing buildings:

  • Roofs: Polyester, wool (best) or fibreglass batts (beware of glass particles) can be installed above ceilings if there is roof space to accommodate it. For flat roofs, the tin must be lifted to do this. You can use:
    • Use R3.5 – R5.0 bulk batts
    • Triple Layer Wave core silver batts on top of that (R6.4 down R 3.0 up)
    • For roofs with no roof space cavity, you can actually create a “false roof” by installing bulk insulation and air cell over an existing roof, then adding fixings for another layer of colorbond or zincalum
  • Walls: Adding insulation to walls is more difficult; it may require wall plaster to be removed first.
  • External brick walls can be reverse clad with an insulation layer then fibreboard. This provides the benefits of thermal mass from the bricks and prevents them heat flows when exposed to direct sun and/or large external temperature variations.
  • Floors: insulate sub floor with R1.5-2.0 bulk batts with a 20mm gap then Air-Cell retroshield
  • Wooden floors: insulate underneath (if 500mm clearance) with R1.5-2.0 bulk then use air cell over joists. If there is unsufficient space underneath, you can lift wood flooring, install insulation, then replace the flooring.

See also