5.1 Thermal insulation
Insulating an existing building doesn’t require a building consent, except for external and fire-rated internal walls. External wall insulation is excluded due to potential weathertightness risks.
What the law says
Schedule 1 of the Building Act 2004
Exemption13. Thermal insulation
1. Building work in connection with the installation of thermal insulation in an existing building other than in:
(a). an external wall of the building; or
(b). an internal wall of the building that is a fire separation wall (also known as a firewall).
How it works
Insulation may be retrofitted in the subfloor and ceiling areas; however insulating external walls and internal fire-rated walls falls outside the scope of this exemption.
What is exempt
- A house is being retrofitted with insulation to the sub-floor and ceiling spaces.
- An existing apartment building is being retrofitted with fibreglass insulation to the internal, non fire-rated walls for additional thermal and noise control.
What needs consent
- The external walls to a house are to be injected with expanding insulating foam.
- A fire-rated tenancy wall to an apartment is to be retrofitted with thermal insulation.