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Landlord Insulation Assessment

Written by Blow Insulation on .

LandLord Insulation Assessment of Existing Insulation

The minimum ceiling and underfloor insulation performance requirements for landlord insulation installed before 1 July 2016 are shown below.

Masonry minimum (Solid construction, including concrete block single-skin brick etc)

Ceiling R 1.5 – Underfloor R 0.9

Timber-framed and other construction minimum

Ceiling R 1.9 – Underfloor R 0.9

Rule of Thumb for Ceiling Insulation Installed before 1 July 2016

The following Rule of Thumb is designed to help people assess whether the existing landlord insulation is likely to comply with the RTA requirements. This applies to homes that have had insulation installed before 1 July 2016. Most homes built after 1 April 1978 should have had insulation installed that was specified to meet the above Construction R-values when it was installed – the specifications should be on the building permit documentation at your Local Council. Homes built after 1 April 1978 with insulation which met thermal requirements at the time of construction is likely to still comply with the Regulations provided the insulation is in reasonable condition.

This Rule of Thumb has been created for the most common types of older ceiling insulation materials – glass fibre insulation, and macerated paper insulation. It may also be applied to blown wool insulation. Most common types of older insulation would have been at least 100mm thick when new, however some settlement or compression can be expected for older insulation. In general, all areas of ceiling insulation should have a thickness greater than 70 mm above all accessible habitable spaces.


Existing Ceiling Insulation Thickness Over Habitable Spaces
Ok Over 100 mm in all places (except safety clearances)
May need topping up Between 70 mm and 100 mm in places
Requires retrofit Below 70 mm in places


Underfloor insulation must cover all accessible parts of the floor below the habitable spaces of the dwelling, except where clearances are required – e.g. for pipework – refer to the New Zealand insulation installation standard NZS 4246 for guidance on required clearances. The insulation must be in reasonable condition – damage such as rips, tears, or salt or dust deposits on the shiny face of foil insulation degrades the performance of foil insulation.

More information on installing insulation can be found at or contact our team at Safe-R Insulation for a free assessment on 0800267992 or at