RibRaft® HotEdge® Range

3000mm L x 25mm D

Firth’s RibRaft HotEdge® range of innovative foundation insulation solutions take another step forward in helping make warmer, drier, healthier homes easier to design and build.   HotEdge Extra® now has a BRANZ test report for a 90mm framing bottom plate anchor solution (BRANZ Test Report ST18050) that meets all NZS 3604 load requirements (>15Kn).  Testing was completed using 20MPa RaftMix concrete, M10 155mm ECKO screw bolts (orange top) and 12mm ECKO Packers. 

HotEdge® systems have been developed to improve the thermal performance of homes with RibRaft® or RibRaft X-Pod® concrete foundations using brick and/or non-brick cladding systems.   Slab edge insulation helps close a buildings thermal envelope which is key to reducing cold spots where moisture can form, creating opportunities for mould to grow.

HotEdge Base® can be used in conjunction with any other RibRaft® product and provides under slab perimeter insulation for improved thermal performance.

These fully integrated thermal solutions are designed and tested specifically with Firth foundation systems to assist in attaining Homestar™ points.  Firth products have been independently tested for proven performance to help you achieve compliance with NZS3604 and the H1, (5th Edition) updates. 

Unique features of our systems are:

  • Quality: RibRaft HotEdge® and HotEdge Extra® systems have been independent tested.
    • HotEdge Extra® BRANZ test report (ST18050) for bottom plate anchor method using 90mm timber framing
    • HotEdge® R-values have been 3D thermally modelled to help you achieve H1 5th Edition compliance.
  • Durability: uses superior materials with rigorous manufacturing processes
    • The robustness of the HotEdge® and HotEdge Extra® means less waste through handing damage on site.
    • Made from XPS, the boards are more resistant to moisture, retaining its R-value year after year.
  • Cost: HotEdge systems help achieve costs savings through:
    • Quicker to design and specify with testing performance and free online design tools
    • The pre-plastered surface helps reduce fi­nishing time.
    • Reduces build times through simple, standardised construction techniques.
  • Easy installation: fits easily inside form work and with regularly space Tornado screws securely integrating HotEdge® and HotEdge Extra® to the concrete slab
    • Fully compatible with all Firth’s RibRaft® systems including RibRaft TC3® and X-Pod®.

Get the Edge with Firth’s full range of durable, seismic and thermally rated foundation systems.  

For more information call 0800 HOTEDGE (468 3343)

Suitable for Foundations

Contact us to find the right product for your project

0800 FIRTH 1



The pending H1 (5th Ed.) updates to the Building Code use a new calculation method to set the minimum R-value requirements for each climate zone.

There are now six Climate Zones (previously three) based on jurisdictional boundaries that take into consideration regional climatic data for more practical insulation levels. 

The Firth H1 R-Value Calculator tool uses the prescribed methodology in H1 (5th Ed.) - Energy Efficiency of the NZ Building Code to calculate the R-value for a variety of different Firth Flooring systems using RibRaft X-Pod®, RibRaft HotEdge Extra®, RibRaft HotEdge Base®.  The R-values calculated are applicable to all housing, and non- residential buildings up to 300sqm only


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