Changes to H1 requirements under the NZBC mean much higher R-values are required in New Zealand buildings — especially those with underfloor heating and in cooler climate zones. This leaves architects with the challenge of incorporating much more insulation, ideally without increasing slab height. The team at MAXRaft have come up with a solution to this problem with MAXRaft Plus+ — a new and improved version of their popular insulated flooring slab designed to exceed new R-values while maintaining the same slab heights.

“The new H1 requirements with underfloor heating mean you have to get higher R-Values. For example in Queenstown the lowest R-value with underfloor heating is 3,” explains Henry Edney, MAXRaft. “We looked at how we could achieve those R-Values while keeping the slab heights the same, as per current building heights. Ultimately, rather than redoing the system, we’ve changed the waffle pod with a solid pod so that we keep the same heights.”

MAXRaft Plus+ is available in two grades — a standard option which uses solid pods comprising 50% recycled and 50% new polystyrene insulation material, and a higher grade option which uses S-grade pods to provide even higher R-values for high performance homes.

Much like MAXRaft original, MAXRaft Plus+ is designed for floor slabs built on less stable ground such as TC2, expansive soils, 200KPA or piled sites. The perimeter insulation, ribs and load bearing thickenings remain the same, but the incorporation of solid pods ensures increased thermal performance to provide a foundation with an R-value between 2.5 and 4.03 depending on design.

The system makes it easy for architects and builders to adapt to the new requirements. “The great thing about MAXRaft Plus+ is that it’s all the same detailing as standard — the heights of floors remain the same, installation is the same, just in a slightly different format,” says Henry.

This means little change when specifying — there’s no height difference in the slab or extra insulation under pods, and the CAD files are similar. And for builders, just like MAXRaft’s other products, the system is supplied pre-cut and is easy to install — and as always, there’s the option for the MAXRaft team to take care of the install too.

Comfortably exceeding the new H1 requirements in all climate zones, MAXRaft Plus+ is suitable for both residential and light commercial projects with underfloor heating. The system is also ideal for Certified Passive House and Homestar 8 - 10 projects — anywhere where exceptional thermal performance is desired. “We’ve already got people taking it up as they want to build better than the new H1 requirements,” says Henry.