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MAXSlab is an insulated, concrete slab-on-ground flooring system for use in residential and light commercial buildings. The MAXSlab features a continuous polystyrene insulating layer beneath the slab and to the exterior perimeter surfaces. The MAXSlab can be designed as an insulated slab-on-grade where ground conditions meet the requirements of 'good ground' as per NZS 3604.

It is based around three components which combine to provide a foundation with an R-value of R3 and above depending on the nature of the site:

  • Perimeter Footings: Designed to both create a thermal break and bear the weight of perimeter walls, these footings reduce heat loss from the floor at the point where up to 80% of such loss occurs.
  • Load Bearing Thickenings: MAXRaft's load-bearing thickenings can support load-bearing walls within the home while maintaining a complete thermal envelope around the foundation.
  • MAXRaft Infill: A cost-effective method of ensuring that the home is properly insulated and a thermal break is maintained throughout. One trailer of MAXRaft to a standard size house (approx 180m²) is equivalent to 24m³ of concrete. 
Key Features
  • Increased thermal efficiency
  • Site-specific engineering
  • Reliable, proven construction details
  • Achieves an R-Value of R3 and above according to floor type
  • Delivered to site in pre-cut segments along with a site-specific panel plan
  • Less time required on site:
    • Can be put down in approximately three hours by a team of two people
    • Then ready to receive the reinforcing later the same day and concrete when ready
  • MAXRaft R-value Calculator — find the product to exceed the requirements of H1
Scope of Use

The MAXRaft Concrete Slab Floor System (MaxSlab) can be used to construct steel reinforced, concrete slab-on-ground floors subject to specific engineering design for buildings within the following scope:

  • Ground floor slabs for timber-framed buildings, within the scope of NZS 3604, or other similar lightweight constructions where they are subject to specific engineering design; and
  • Built on 'good ground' as defined by Acceptable Solutions and Verification Methods for NZBC Clause B1 Structure; or,
  • Built on 'TC2' type ground within the 'Canterbury earthquake region' or moderately to highly expansive soils, subject to verification and assessment by a Chartered Professional Engineer

See BRANZ Appraisal 1054 for full information.

  • Use the MAXRaft R-value Calculator to find the product from the MAXRaft range to meet & exceed the requirements of H1
Statement of Building Code Compliance

If designed, used, installed and maintained in accordance with the statements and conditions of the BRANZ appraisal, the MAXRaft Concrete Slab Floor System (MaxSlab) will meet the following provisions of the NZBC:

  • Clause B1 Structure: Performance B1.3.1, B1.3.2 and B1.3.4. the MAXRaft Concrete Slab Floor System meets the requirements for loads arising from self-weight, imposed gravity loads, earthquake, wind, differential movements and time dependent effects including creep and shrinkage. [i.e. B1.3.3 (a), (b), (f), (h), (m) and (q)]. See Paragraphs 7.1 – 7.2
  • Clause B2 Durability: Performance B2.3.1 (a) not less than 50 years and B2.3.2. MAXRaft Concrete Slab Floor System meets these requirements. See Paragraphs 8.1 – 8.3
  • Clause E2 External Moisture: Performance E2.3.3. The MAXRaft Concrete Slab Floor System meets these requirements. See Paragraphs 10.1 – 10.3
  • Clause F2 Hazardous Building Materials: Performance F2.3.1. The MAXRaft Concrete Slab Floor System meets this requirement and does not present a health hazard to people.
  • Clause H1 Energy Efficiency: Performance H1.3.1 and H1.3.2E. The MAXRaft Concrete Slab Floor System contributes to meeting these requirements. See Paragraphs 12.1 – 12.2

See BRANZ Appraisal 1054 for full information.

B1 Structure compliant
B2 Durability compliant
E2 External Moisture compliant
External Moisture
F2 Hazardous Building Materials compliant
Hazardous Building Materials
H1 Energy Efficiency compliant
Energy Efficiency
MAXRaft R-value Calculator
Technical Resources
BRANZ Appraisal 1054

1054 [2019]

Product Guide


CAD/PDF Details
MAXRaft Products
MAXSlab 300
MAXSlab 350
MAXSlab 400

Build a healthy and more cost effective home from the foundation up with MAXRaft, New Zealand's premier fully insulated concrete slabs.

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