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BCA Thermal Requirements (R-Value)  


Suspended floors which form part of the Building envelope, including a floor above or below a car park or plant room, must achieve the total R-Value specified in the tables below.

Building Class 2 to 9  > BCA 2011 Table J1.6

Building Class 1 & 10 > BCA 2011 Table

Roof and Ceilings

A suspended slab that forms part of a roof, or ceiling, must comply with the insulation requirements of Table J1.3 (refer BCA) 

Building Class 2 to 9 > BCA 2011 Table J1.3a & J1.3b

Achieving the Required R-Value 

In most instances one, or all, of the following components (additional to the concrete slab) will need to be included in the Floor or Roof/Ceiling "Thermal System" in order to achieve the required minimum R-Value.

  • Air Film
  • Air Gap (space/void)
  • Insulation
  • Floor Covering
  • Ceiling Material

The following table has been reproduced from the National  Precaster (NPCAA) and shows the total R-Value for a typical Ultrafloor Thermal System (floor).   

Typical Ultrafloor Slab - Floor Assembly



Typical Ultrafloor Thermal Systems




ROOF /  CEILING                        


Thermal Calculator

Download ULTRAthermal

The ULTRAthermal software is free to download and enables you to easily check the total R-Value for any Ultrafloor slab system. 

Program features include:

  • Full beam range selection
  • Adjustable infill size and type
  • Variable concrete topping depth
  • Multiple ceiling types
  • Multiple insulation types
  • Multiple floor coverings
  • Printable system details
  • Printable thermal certification  

For Thermal design assistance please call 1800 858 723 or email