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

Published: 28 May 2024

Firth HotEdge® has been developed to help improve the thermal performance of homes with concrete foundations and any cladding system.

The HotEdge® range of XPS insulation panels have been specifically designed and tested to work with RibRaft and X-Pod foundations. They are quick to install using standard building techniques and come pre-plastered to reduce finishing time (no plastering needed on site).

HotEdge® insulation is not just about R-values, it also helps close a building’s thermal envelope to reduce cold spots at thermal bridges between slab and timber framing. This reduces the chance of moisture forming which could otherwise lead to mould.  This means a warmer, drier, healthier home.

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

Benefits of HotEdge® systems are:

  • Quality
    • Warmer and therefore more efficient and healthier homes
      • Reduce/eliminates cold points at wall / slab junction created by thermal bridging (cold spots = mould spots)
    • Proven R-values based on HotEdge® 3D thermally modelling
  • Durability
    • The robustness XPS compared to EPS means less waste through handling damage on site.
    • XPS boards are more resistant to moisture.
  • Support
    • Dedicated systems technical support to answer any specifying or installation questions.
  • Cost saving:
    • Quick to install saving labour cost for builders and foundation specialists
    • Free online design tools and BRANZ testing (ST18050) make it quicker to design with and specify
    • Reduces build times through simple, standardised construction techniques.
      • The pre-plastered surface helps reduce finishing time.
    • Easy installation
      • Uses standard construction method.
      • Fits easily inside form work and with regularly space Tornado screws for a secure integration to the concrete slab.
      • Fully compatible with all Firth’s RibRaft® systems: RibRaft TC3®, X-Pod® and other pod systems such as ClevaPod® .

Firth has developed online resources to help specifiers to easily calculate and design for slab foundation insulation requirements. These are free to use. The Firth online R-Value Calculator calculates an H1 R-value solution for your concrete foundation.  WaffleSuite enables quick designing of RibRaft X-Pod® foundations for complex soil types and helps calculate a custom thermal solution for your project.

HotEdge® Extra® has a BRANZ test report (ST18050) for a 90mm framing bottom plate anchor solution that meets all NZS 3604 load requirements (>15Kn) for bracing systems e.g. Handibrac. Testing was done with 20MPa RaftMix concrete, M10 155mm ECKO screw bolts (orange top) and 12mm ECKO Packers.

Learn more at: or 0800 HOTEDGE (468 3343)