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ThermaStar™ is a premium grade of expanded polystyrene from RMAX manufactured to exceed Class H or VH of the Australian Standard AS 1366, Part 3-1992 for expanded polystyrene block materials combined with foil facing on both sides of the sheet.

ThermaStar™ is produced in various thicknesses to suit customer needs. The strength and excellent insulation performance characteristics of ThermaStar™ make it ideally suited as thermal insulation in floors, walls and roofs of commercial and high density residential buildings. ThermaStar™ products are free of ozone depleting substances.

Delivering ‘Life of Structure’ Six Star Energy Savings

While RMAX ThermaStar™ is manufactured typically in high densities (24 and 28 grams/litre) from RMAX Expanded Polystyrene (EPS) density can and is customized to deliver the required R value for the particular application on site.

Combined with the exceptional reflective qualities of aluminium foil, it produces excellent thermal insulation, assisting to provide the crucial six star energy rating as per BCA 2010 section J for insulation. The combination of EPS and foil enables RMAX ThermaStar™ to reflect up to 97% of radiant heat.

As it does not deteriorate over time, RMAX ThermaStar™ provides a consistent high level of insulation for the life of a building through massive gains in R values.

Physical Properties- ThermaStar 28

Physical Property Units ThermaStar™24 ThermaStar™28 Test method
Compressive Strength @10% deformation, min. kPa 135 165 AS 2498.3
Cross-breaking strength, min. kPa 260 360 AS 2498.4
Rate of Water Vapour Transmission, max. measured parallel to rise @23°C g/m2.s 460 350 AS 2498.5
Dimensional Stability of length, width, thickness, max. @ 70°C over 7 days percent 1 1 AS 2498.6
Core EOS Thermal conductivity max. W/mk 0.0366 0.0350 AS/NZS 4859.1
Thermal Resistance, R, min. Concrete sub floor*-
*Note - Based on 180 mm concrete, 80 mm air gap, 30 mm ThermaStar™*
4.7 - Down (winter)
2.7 – Up (Summer)
AS/NZS 4859.1
Fire Resistance( cone calorimeter)
Group 1 Group 1 AS/NZS 3837
Early Fire Hazard Properties
  • - Ignitability Index- scale 0-20
  • - Spread of Flame Index –scale 0-10
  • - Heat Evolved Index – scale 0-10
Smoke Produced Index- scale 0-10








AS/NZS 1530.3
Foil Emmitance
0.03 0.03 AS/NZS 4859.1
Surface Corrosion
Pass Pass AS/NZS 4859.1
Wet/Dry Delamination
Pass Pass AS/NZS 4859.1
Apparent Bulk Density,core material min. g/L 24 28 ISO 845

RMAX ThermaStar™ is a versatile insulation medium, providing solutions to builders and designers seeking to achieve the six star energy rating.

Example of R values for Common RMAX ThermaStar™ systems:

The following table represents typical R value using ThermaStar™ 28 in different building systems:

System Thickness Summer R Value* Winter R Value*
Concrete roof 30mm 2.5 2.3
Concrete roof 50mm 2.9 3.1
Concrete floor 30mm 2.2 2.5
Concrete floor 50mm 2.8 3.0

Verification Information

* These R values are have been verified in accordance with AS/NZS 4859.1:2/Amdt 1 2006. The values published are based on determinations based upon AS/NZS 4859.1:2/Amdt 1 2006, Material for Thermal Insulation of buildings and the Australian Institute of Refrigerations Air-Conditioning & Heating (AIRAH) Handbook (2007 Edition). Calculations incorporate dust assumptions of AS/NZS 4859.1:2002/Amdt 1 2006. Total R values are for the insulation path only and include indoor and outdoor air films. Cavity air space insulation values were estimated using Reflect 3 software using infra-red emmittances e1 and e2 and defined air gaps. The results have been independently verified as per the requirements of AS/NZS 4859.1:2002/Amdt 1 2006.

Emissivity and Reflectivity

Emissivity is the amount of radiant heat energy emitted or radiated from the surface. The lower the emissivity value the greater the insulation protection from radiant energy transfer.

Reflectivity is the ability a surface has to reflect radiant heat energy. The higher the reflectivity, the less potential a material has to absorb radiant heat, the less heat is conducted through its mass and emitted or re-radiated through the opposite side.

With the low thermal conductivity of RMAX EPS and utilizing the reflective properties of aluminium foil RMAX ThermaStar™ significantly reduces heat transfer through walls, floors and ceilings.