In New Zealand, the installation and repair of foil insulation is banned for residential buildings in ceiling, walls and underfloor areas. This legislation can be found under section 26 of the Building Act 2004. Any person breaching the ban can be fined for up to $200,000 as it is considered as an offence under this Act.
The Chief Executive of the Ministry of Business, Innovation and Employment has banned foil insulation due to safety reasons. The main risk is electrocution while installing or repairing the foil insulation. Being metallic, it conducts electricity and can become live if it encounters electrical wiring. In retrofit condition, foil is usually stapled in the floor or ceiling joists, mainly in darkness, so it is difficult to see where the electric wires are. If the staples are pierced on the live electric cables, it then presents a serious electrocution hazard. Even if the installation is completed in retrofit without any hazards, you are still leaving it electrically live, presenting a future electrocution hazard.
According to the Building Act, foil insulation should not be used for any other purposes. This is because the installation method will be the same, and therefore the associated risks still apply. Another purpose people might want to use foil insulation for is a ground vapour barrier (laid over the ground to prevent the evaporation of water, which leads to dampness and mould). Around 1L of water can evaporate every day from just 4 square metres of ground, so a moisture barrier makes for a warmer home. Rather than using foil for this purpose however, Bay Energy Solutions strongly recommends using plastic, as it is both safer and more versatile.
If the foil is torn, damaged or no longer shiny, it should then be replaced with bulk insulation. Once again, it should not be repaired, as this is illegal for NZ residential buildings. While removing the foil insulation, make sure the power is turned off first, and you follow the guidelines of ECP 55 (Electric Code of Practice).
If your property has foil insulation, and you are not sure what to do, contact Bay Energy Solutions for a free home assessment. Our experts can talk to you through the best options available for your home, and provide a free cost estimate if necessary.