Marmox Insulation Boards for Underfloor Heating Installations
Marmox Multiboard is a lightweight, durable thermal tile backer board that insulates, waterproofs, and provides the perfect base for tiling. It is your all-in-one solution designed to insulate the floor surface. It improves the performance and efficiency of electric underfloor heating by directing warmth upwards into the room rather than downward into the slab.
Nationwide
Distribution
20 Years
Warranty
Free Technical Support
Before and after install
Superior Thermal Insulation
Marmox insulation boards are placed between the concrete slab and the heating system to create a thermal barrier, ensuring all energy is directed upwards instead of being dispersed throughout the concrete slab. This reduces heat loss by up to 50% and speeds up tile warm-up times to just 15–20 minutes. Insulation for heated floors is now required by the NZ Building Code, and Marmox exceeds this standard in most cases.
Made from an XPS closed-cell structure, the boards are 100% waterproof and rot-proof, making them ideal for wet areas. They boast a compressive strength of 40 tons/sqm and reduce footfall noise by up to 20 decibels.
Supplied in 1250mm x 600mm panels (6mm or 10mm thickness), the boards are installed using a flexible tile adhesive.
Why Warmup Recommends Marmox Insulation
The efficiency of an electric underfloor heating system depends heavily on how well heat is directed toward the room above, rather than lost into the slab or subfloor below. Warmup recommends Marmox insulation boards in the following scenarios:
- Undertile heating in bathrooms — provides a waterproof, insulated substrate and improves heat-up speed
- Heated concrete slab applications — the thermal barrier directs heat upward rather than letting it disperse into the slab
- Wet area applications — the completely waterproof XPS structure suits shower floors and bathrooms
- Any installation where energy efficiency or acoustic performance is a priority
Complete Your Heated Floor Specification with Marmox
Warmup supplies Marmox insulation boards alongside the full Warmup underfloor heating range. Contact our New Zealand team for a complete specification covering insulation, heating, and thermostat products for your project.
Marmox Multiboard
A rigid XPS insulation board for bathroom floors and general heated-floor applications. Placed between the subfloor and the heating system, it creates a thermal barrier that directs heat energy upward.
- XPS closed-cell structure, completely waterproof, won’t absorb moisture or rot
- Compressive strength of 30 tons per square metre for a stable, load-bearing substrate
- Reduces footfall noise and tiled-area echo by up to 20 decibels
- Available in 1250mm x 600mm boards, in 6mm or 10mm thickness
- Installed with a flexible tile adhesive
- BRANZ appraised – Appraisal #895-2023
- Compatible with Warmup underfloor heating systems
Marmox Multiboard FAQs
A: Recent changes to the NZ Building Code require heated floors in new homes to be insulated, and Marmox exceeds this requirement in most cases. Beyond compliance, insulation significantly improves the performance of any underfloor heating system by directing heat upward into the room rather than letting it disperse into the slab, which reduces running costs and speeds up heat-up time.
A: It depends on your room’s area relative to its exterior wall length. As a guide: divide your room’s floor area by the length of its exterior (perimeter) wall. If the result is greater than 1.6, a 6mm Marmox multiboard will comply. If the result is between 1.3 and 1.6, a 10mm board is required. For example, a 3m x 3m room (9m²) with only one exterior wall (3m long) gives a ratio of 3 — well above 1.6 — so 6mm board complies. The same room with two exterior walls (6m of perimeter) gives a ratio of 1.5, requiring 10mm board. Warmup’s technical team can confirm the right specification for your specific project.
A: Yes. The XPS closed-cell structure is completely waterproof and won’t absorb moisture or rot, making Marmox boards well suited to wet area applications including shower bases and bathroom floors.
A: After switching on the heating system, floor tiles typically reach temperature in around 15–20 minutes, even over a cold concrete floor.
A: Yes. Marmox boards reduce footfall noise and the echo commonly associated with large tiled areas, by up to 20 decibels.
A: Marmox boards have a compressive strength of 30 tons per square metre, which keeps the floor’s structural integrity intact under load.
