EXPOL Platinum Board for Concrete Floor Insulation

A warm, dry, healthy home starts at the foundations.  EXPOL Platinum Board provides high-performance thermal insulation under concrete floors. 

By adding graphite to expanded polystyrene (EPS), EXPOL has created one of the most effective insulation boards available for residential construction.

A lightweight product with a unique matrix structure, EXPOL Platinum Board achieves exceptional insulation and strength for its thickness.  

When superior R-value and strength is needed, look for the black board - EXPOL Platinum Board.

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Choose your thickness


Concrete Floor Insulation

A lightweight board, EXPOL Platinum Board is quick and easy to install under concrete slabs.  Supplied in sheets ranging in size from 2400mm to 4800mm, EXPOL Platinum Board is ideal for use where insulation thickness is restricted, and high R-values are required.

For applications where a high load is probable, use EXPOL ThermaSlab VH.  For a cost effective solution, use EXPOL ThermaSlab S or H.  Or use EXPOL-X, an extruded polystyrene product with extremely high compressive strength.

Other Applications

EXPOL Platinum Board is also suitable for use in wall insulation, masonry wall insulation, cladding insulation and skillion roof insulation.


Suitable for use in floors, walls, and roofs, EXPOL Platinum Board creates comfortable living spaces and reduces heating and cooling costs.  Used under a concrete slab, EXPOL Platinum Board exhibits excellent absorption properties and reduces noise.

Exhibiting superior moisture resistance and compression strength, EXPOL Platinum Board has a reputation for reliable performance as an under slab insulation product.  

Compared to high density EPS, Platinum Board uses fewer raw materials during processing, without compromising insulation performance.  EXPOL Platinum Board is one of the most eco-efficient choices for underfloor insulation.  At a thickness of 50mm, EXPOL Platinum Board delivers an R-value of 1.56.  

EXPOL Platinum Board comes in a range of sizes and thicknesses making the installation process efficient. Special sizes are available on request.




Once EXPOL Platinum Boards are laid, mesh chairs are placed on the board ready for reinforcing mesh.  EXPOL supplies bar chairs for steel mesh support.



EXPOL Platinum Board comes in five lengths at 1200mm wide.  Special sizes are available.




All sizes above are examples of some standard situations
NOTE: Other widths available


EXPOL makes insulating easy.  To ensure you get the best result, follow these simple steps.

Installing EXPOL Platinum Board

To install EXPOL Platinum Board, simply place sheets on top of polythene (DPC) and ensure sheets are not placed under any footings or thickenings for load-bearing walls.

Sheets can be taped together, however, this is not a necessity.  Once sheets are laid, place reinforcing mesh over the top using mesh chairs.

See our Masterspec document for further information.

Technical information



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

EXPOL Platinum Board and EXPOL ThermaSlab have the same physical characteristics and are both excellent choices for concrete floor insulation.  EXPOL Platinum Board has the addition of graphite that gives a higher R-value for greater thermal insulation performance.

How strong is EXPOL Platinum Board?

The unique matrix structure of expanded polystyrene (EPS) creates block rigidity and compressive strength making it an excellent choice for use under concrete floors.  An inert, rigid foam product, EPS holds its shape and does not deteriorate with age. EPS is often used for commercial applications as structural base infill as well as road and bridge infrastructures.

Is EXPOL Platinum Board water resistant?

EXPOL Platinum Board is virtually unaffected by water, performing better than other insulation products on the market.  Tests on EPS board retrieved after 30 years underground showed less than 1% water content. Tests taken on EPS board periodically submerged over the same period of time showed less than 4% water content.  

Does EXPOL Platinum Board come in a range of sizes?

Yes, EXPOL Platinum Board is available in lengths of 2400mm, 2450mm, 2700mm, 3600mm and 4800mm at a width of 1200mm.  It is also available in other widths upon request.


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

View Expol Distributors in a larger map

Other Concrete Floor Insulation products which may be of interest

EXPOL ThermaSlab S and H Grades

EXPOL ThermaSlab VH Grade


EXPOL-X Edging

Fast Facts
  • A thin, lightweight board, EXPOL Platinum Board is fast and easy to install.
  • With the highest R-value of all of EXPOL’s EPS concrete floor insulation products, EXPOL Platinum Board is an excellent choice for concrete slab insulation.
  • EXPOL Platinum Board is one of the most eco-efficient choices for insulation, yet it does not compromise on performance. 
  • Choose EXPOL Platinum Board to reduce impact noise on floors.
  • The addition of graphite to the EPS gives EXPOL Platinum Board superior insulation and absorption performance.
  • Made of 98% air, EPS does not settle over time, thus ensuring the R-value is maintained for the life of the building.

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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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