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EXPOL R1.4 White Underfloor Insulation is rigid Expanded Polystyrene panel designed to fit between the joists under a timber floor. It is used in normal urban home environments.

It is ideal to use in personal houses or properties which are tenanted. The New Zealand’s Residential Tenancies Act requires landlords to ensure all tenanted properties have proper floor and ceiling insulation. EXPOL UnderFloor Insulation meets and exceeds the requirements of the Act.

For products designed to meet the updated H1 requirements of the Building Code please visit EXPOL New Generation R2.5 Underfloor or EXPOL New Generation R3.1 Underfloor.

EXPOL UnderFloor Insulation products are independently certified by BRANZ – the organisation which is responsible for testing and approving performance of building products in New Zealand.

EXPOL UnderFloor Insulation is available from participating hardware stores nationwide – find your local outlet here.

EXPOL R1.4 - 360 White UnderFloor Insulation

EXPOL R1.4 - 410 White UnderFloor Insulation

EXPOL R1.4 - 470 White UnderFloor Insulation

EXPOL R1.4 - 560 White UnderFloor Insulation

EXPOL UnderFloor R1.4 White Insulation is available in 4 convenient joist widths 360, 410, 470, 560 (mm). Quick and easy to install it is long-lasting insulation that creates a warm, dry home which is healthier to live in and costs less to heat. It can be used on new and existing timber floors and fits snugly between timber floor joists to stop drafts and damp from entering.

EXPOL UnderFloor R1.4 White Insulation is made of rigid polystyrene, so it won’t sag over time. It is also manufactured with flame retardant, is vermin resistant and helps reduce noise from timber floors.

EXPOL UnderFloor R1.4 White Insulation contains recycled content and can be easily recycled.



The benefits:

  • Easy to install
  • Concertina edges which allow for compression of up to 20 mm to create a tight fit
  • Contains recycled content and can be easily recycled
  • Flame retardant
  • Rigid
  • Resistant to moisture
  • No nutritional value to vermin, birds or animals
  • Ideal for both retro-fit applications and new floors
  • BRANZ Appraised and comes with a 50 year product warranty

All EXPOL timber floor insulation solutions comply with the Australian and New Zealand Standard AS/NZS 4859.1:2002.

All panels have a yellow stripe down one edge to confirm compliance with manufacturing standard AS 1366 Part 3 1992 for SL grade.

It is used as an insulation solution for:

   Timber UnderFloor



Underfloor Pack

Panel Sizes

EXPOL White R1.4 Underfloor Insulation

Product Properties

EXPOL Underfloor Insulation



EXPOL Installation Components

EXPOL Wireguard

EXPOL WireGuard

Where EXPOL R1.4 or R1.8  is exposed to electrical cables us EXPOL WireGuard  a waxed paper strip  to separate exposed electrical cables from the EXPOL R1.4 or R1.8 insulation. Expanded Polystyrene in some cases reacts with the plasticiser and degrades the elastic properties of some electrical cables over a prolonged period.


  • Existing Floors: EXPOL Z Clips are designed as a push fit between the panel and the joist.  
  • New Floors: A 60mm Galvanized Nail should be used to support and secure the panel.
EXPOL Styro-Fix Construction Adhesive

Styro-FIX Construction Adhesive

Styro–FIX is an advanced single component polyurethane-based construction adhesive.

This powerful adhesive is developed especially for the construction industry and will bond most types of construction materials including timber (damp and dry), concrete, plasterboard, polystyrene and many other porous and non-porous substrates.

It bonds expanded polystyrene to most surfaces, delivers strong adhesion and rapid cure, it is gun-able and non-drip.



EXPOL Technical Product Guide

EXPOL Timber UnderFloor Insulation Brochure


Technical Data Sheet

EXPOL R1.4 White UnderFloor Insulation


Building Product Information Sheet

EXPOL Timber UnderFloor Insulation

Where To Buy EXPOL


EXPOL products are available at a number of leading building products stores. Find your nearest stockist here.

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