Are you looking to save time and effort, without a reduction in quality? Not only does Ribraft offer just that, but it does so whilst providing  increased strength and superior insulation.

Developed by Firth 20 years ago, it has become one of the most common and popular flooring and foundation solution across New Zealand. Whether residential or light commercial building projects, Ribraft has garnered acclaim for its innovative design, not only providing faster build times, but also an increase in “seismic strength”. How does it achieve this? Ribraft differentiates itself from other foundation solutions that require footing excavation to place them in the ground. Instead, Ribraft is an “on ground” system. By removing the need to dig trenches for footing, substantial time and labour expenses are reduced, as well as the need for extra sub-traders. Furthermore, Ribraft components are not affected by rain, so often work is able to continue even during wet weather.

The Ribraft concrete foundation system incorporates the use of reinforced ground beams, “ribs”, polystyrene pods and spacers. Whatever your desired construction project is, Ribraft can be laid out in accordance to your foundation plans. The components simply fit together, drastically reducing labour time, before they are topped with concrete. The use of additional structural piles are also incorporated into the system in cases where poor soil or ground quality requires the foundation to penetrate into the stronger soil below to reduce horizontal slipping.

Ribraft’s innovative design offers significantly increased strength and reduced cracking. This allows the rafts to be placed on  soils with a minimum ultimate bearing capacity of 150kPa (for a single storey light roof/wall house). A reinforced concrete perimeter beam and reinforced concrete ribs over the floor area results in a slab of incredible strength.

The insulation benefits of a Ribraft floor (known as the “R value”) are excellent in thermal efficiency. Ribraft exceeds all the minimum requirements for H1 Energy Efficiency by varying amounts.

So to sum up all of the advantages:


  • Seismically strong
  • Energy-efficient concrete floors (due to the incorporation of polystyrene pods)
  • Great thermal rating and compatible with underfloor heating.
  • Labour and cost savings (by removing the need to dig footings)
  • Cleaner construction, with far less excavated material and waste


If you are after a concrete specialist in the Auckland area, or want to know more about the RibRaft foundation solution, contact Jamie and the team at Build2 today!

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