EXPOL ThermaSlab SL Grade for Wall Protection

A high performance, solid insulation solution, EXPOL ThermaSlab SL an economical way to achieve Building Code requirements for wall insulation.

EXPOL ThermaSlab SL is suitable for insulating timber and steel framed buildings and its rigid foam properties ensure it will not sag or decay over time.

Made from durable expanded polystyrene (EPS) foam, EXPOL ThermaSlab is the easiest way to achieve a warm, dry, healthy home.

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Wall Insulation

A lightweight board, EXPOL ThermaSlab is quick and easy to install and provides reliable wall insulation for steel and timber frame buildings.  The rigid foam composition of EXPOL ThermaSlab ensures it will not slump or sag within wall cavities. Available in a range of sizes, EXPOL ThermaSlab is also available in custom sizes.

For a premium solution that offers superior R-value, use EXPOL Platinum Board.

Other Applications

EXPOL ThermaSlab is also suitable for use in concrete slab insulation, retaining wall insulation, cladding insulation and skillion roof insulation.


20% - 30% of a building’s heat is lost through uninsulated walls.  A building insulated with polystyrene wall insulation creates comfortable living spaces for occupants.  

EXPOL ThermaSlab SL is a lightweight polystyrene board that does not compromise on insulation performance.  Its cellular structure ensures that moisture cannot affect the thermal performance of the board.

An exceptionally durable product, EXPOL ThermaSlab SL does not require maintenance or replacement. Thermal performance and resistance to moisture and water will last for the life of the building.  EXPOL’s expanded polystyrene insulation does not decay or rot and has no nutritional value to termites or rodents.

EXPOL ThermaSlab SL is easy to cut and comes in a range of sizes, making the installation process fast and efficient.  

EXPOL also supplies EXPOL Platinum Board for a premium solid insulation solution.




EXPOL Wireguard is a waxed paper strip that separates exposed electrical cables from EXPOL ThermaSlab SL insulation.  An important part of the system, EXPOL Wireguard prevents the degrading effect that EPS can sometimes have on electrical cables over a prolonged period. 




EXPOL ThermaSlab comes in five lengths at 1200mm wide.  Special sizes are available on request.



Technical information



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

View Expol Distributors in a larger map


What’s the difference between EXPOL ThermaSlab SL and EXPOL Platinum Board?

EXPOL ThermaSlab is a cost effective way to insulate a building and meet Building Code requirements. EXPOL Platinum Board is a premium product with superior R-value.

How strong is EXPOL ThermaSlab?

The unique matrix structure of expanded polystyrene (EPS) creates block rigidity making it an excellent choice for wall cavities as it will not sag or slump over time.  

Is EXPOL ThermaSlab water resistant?

The closed cell construction of expanded polystyrene (EPS) ensures it resists any adverse effects of water.  EPS board in wall cavities holds its shape, structure and thermal properties for the life of the building. 

Does EXPOL ThermaSlab SL come in a range of sizes?

Yes.  EXPOL ThermaSlab SL is available in any width. Sheets of 355mm or 555mm at a length of 1200mm are most common.  It is also available in custom sizes upon request.

Is EXPOL ThermaSlab environmentally friendly?

Made from 98% trapped air, EXPOL ThermaSlab requires very little raw material for manufacture making it so efficient that it will save up to 200 times its own resource in energy savings.  All EXPOL expanded polystyrene (EPS) products are 100% recyclable.  EXPOL runs one of New Zealand’s largest EPS recycling plants.

Does EXPOL ThermaSlab give off toxic fumes?

In the event of a fire, the level of toxicity of EPS is no greater than timber.  EPS does not off-gas hydrogen cyanide or hydrogen chloride.  No CFCs or HCFCs are used in the manufacture of EXPOL Platinum Board.

Other Expol Wall Insulation products which may be of interest

EXPOL Platinum Board

Fast Facts
  • A thin, lightweight board, EXPOL ThermaSlab is easy to install by a tradesman or handyman.
  • Extremely durable, EXPOL ThermaSlab does not allow thermal gaps by sagging or slumping over time.
  • EXPOL’s expanded polystyrene insulation boards significantly improve the energy efficiency of a home requiring less drain on resources for heating and cooling.
  • EXPOL ThermaSlab SL is a cost effective way to meet Building Code requirements for wall insulation.
  • EXPOL ThermaSlab SL does not require maintenance for the life of the building, as it is resistant to moisture, rot and pests.
  • EXPOL manufactures EXPOL ThermaSlab polystyrene boards throughout New Zealand, ensuring quick and easy delivery to site.

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Enquiry Form

General Enquiry

Tel: +64 (9) 634 3449

Free Phone: 0800 86 33 73


105 Captain Springs Rd., Onehunga, Auckland

Tel: +64 (9) 634 3449

Free Phone: 0800 86 33 73


105 Captain Springs Rd., Onehunga, Auckland

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