We are coming across underfloor insulation where new polyester insulation has been installed over the top of old foil insulation.

NZS4246-2016 requires old foil insulation to be removed before any new insulation is installed.

For rental properties, all insulation must be installed to NZS4246-2016. So this scenario becomes a fail.

You then need to remove the new insulation, which tears it and means it cannot be reused, remove the foil and then install new insulation all over again.

This can turn a 100m² job from costing around $2000, including the foil removal, to a total cost of $4400.

Our advice is to always use experts who understand and work to NZS4246-2016 to ensure your property is compliant to the required standards.

• Kevan
• 12 March