Benefits for Designers and Specifiers

Why Specify MAXSlab®?

As society changes, along with the economy and environment, changes are happening in the way homes are built. People are beginning to become more concerned with the environmental and health impact their home will have, and with the amount of energy it uses. Those involved in specifying higher quality, sustainable building materials that meet these needs are moving to the fore. A fully insulated MAXRaft® is a great way to start any design.

It is important to take the thermal efficiency of products into account when selecting the right product for your client. The thermal properties of a building, along with its thermal mass performance, ultimately impact on the energy used in heating and cooling a home. MAXSlab® products can offer R-Values of approximately R4, allowing the homeowner to decide how much energy they use, rather than have it dictated by the weather.

MAXSlab® products are user-friendly for contractors, any leftover polysytrene waste is recyled following the concrete pour.




Why MAXSlab®

Performance Benefits

Today's homeowners want systems that have high thermal performance which provide increased energy efficiencies, prevent heat loss through the slab, neutralize thermal bridging and provide health and comfort benefits throughout their lifetimes. These elements help home owners minimize energy costs while increasing property values for owners. As programmes like Homestar™ creep into the public conscious, and insulation regulations creep up, homeowners will continue to demand improvements in the products used in their homes. MAXRaft® products meet and surpass all these requirements, with R-values of approximately R4.5 depending on the site, your clients won't have worries about their foundation heating their flowerbed.

Energy Efficiency

MAXRaft® fully insulated foundations greatly reduce heat loss through the slab. With high R-values of ~R4.5, this greatly increases energy efficiency, resulting in lower heating costs for the homeowner and greater comfort in the home environment. One of our clients has calculated the cost of underfloor heating for his home at 60.2c/m2 per month.

As an official partner of Homestar™, MAXRaft® can help your clients reach the upper end of the star rating (6 Homestar and above), and in the case of multi-dwelling projects in Auckland, ensure that your client will not fall foul of the 6 Homestar minimum for slab insulation.

If you want to see what the R-value could be on your client's home, please click here for our H1 calculator.

Iso-thermal analysis conducted by EZED Ltd in line with ISO 10211 comparing MAXRaft® to a traditional waffle slab show MAXRaft® is significantly warmer, providing comfortable warmth even in the middle of a South Island winter -0°C climates.


With site-specific design, MAXRaft® can be guaranteed to suit your client's structural requirements. All MAXRaft® fully insulated foundations are designed to ensure that the foundation matches the ground type on site, as well as taking into account all load bearing walls and point loads. Our engineers use standard details where possible in order to keep MAXRaft® as easy to use as possible.

Whether you are using a lightweight cladding, exterior bricks or stone cladding, we can come up with a solution for you.


MAXRaft® is currently constructed using different grades of New Zealand made CFC-free Expanded Polystyrene (EPS). An environmentally friendly product, EPS has long been used in the construction industry for providing lightweight, effective insulation.

We will shortly begin introducing a CFC-free Extruded Polystyrene (XPS) option for perimeter footings and internal thickenings. With a compression strength of 300kPa, our XPS will in many cases be firmer than the ground upon which it will be laid, providing a superior base for any load bearing walls within a home.


As a result of the insulating properties of MAXRaft®, any concrete poured on top of it takes a bit longer to cure than concrete in traditional slabs. This extended curing results in a stronger concrete floor, which is more crack resistant than traditional methods. If you are using polished concrete floors within a house, MAXRaft® can help lower the possibility of unwanted cracks ruining a beautiful finish. We recommend Multiform's Ultrafibre 500 be used in conjunction with MAXRaft®.

As seen in the iso-thermal analysis above, MAXRaft® helps retain heat in the foundation and thus leads to a higher temperature at the junction of wall and slab when compared to traditional methods. This higher temperature reduces the likelihood of moisture condensation building up in these corners, and thus avoids the buildup of spotty mold in these corners.