As we head into an era where energy efficiency and sustainability defines how homes are designed and built, Firth have developed a new edge slab insulation system called RibRaft® HotEdge

®RibRaft® HotEdge® was designed with input from one of New Zealand’s leading Universities, BRANZ and industry partners. In addition, BRANZ 3D modelled Ribraft® for thermal performance with and without edge insulation. Results showed, when using RibRaft® HotEdge® a minimum of R1.0 was achieved to the edge beam, increasing the overall R-value to the floor area of up to 50% (refer to BRANZ insulation guide 5th Edition).

The Firth RibRaft® HotEdge® System has been designed specifically for Firth RibRaft® floors, it is a fully integrated edge slab insulation system that assists in attaining Homestar® points.


  • It is placed inside the RibRaft® foundation boxing before Firth RaftMix® concrete is poured. Tornado screws allow it to be structurally connected to the Firth RaftMix® concrete edge beam, making it an integral part of the foundation.
  • RibRaft® HotEdge® is a closed cell extruded insulation system, with a pre-meshed and plastered exterior that provides high strength (up to 10 times stronger than expanded polystyrene insulation – EPS), durability and is highly resistant to moisture, retaining its R-value year after year.
  • For increased durability, the system has the inherent toughness of aluminium corner protectors, which are easy to install.
  • With the RibRaft® HotEdge® system you don’t need to increase the framing size in your design: standard 90mm framing applies.
  • The system is fully compatible with Firth’s RibRaft EQ® and RibRaft TC3® foundation systems.

Screen Shot 2017-03-02 at 11.12.23 PM

Say something!