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Marmox Multiboard

Marmox insulation boards are thin sheet boards designed to insulate the floor surface of new or existing buildings, saving up to 50% of the heat lost with conventional underfloor heating. This will significantly improve heat-up time and greatly reduce running costs. When used over the wooden floor, Marmox also acts as a tile backer and will not absorb moisture when used in bathrooms or wet areas.

This insulated tile backer board is made of extruded polystyrene, reinforced, and covered on both sides with a fibreglass mesh embedded into a thin cement polymer mortar. The individual board is 1250mm long X 600mm wide with an optional thickness of 6mm or 10mm. It is installed using a flexible tile adhesive in a similar manner to a large tile.

Key Features
  • BRANZ Appraised
  • Excellent heat insulation
  • Completely water-resistant
  • High compressive strength
  • Excellent acoustic properties
  • Lightweight and easy to work with/install into new and existing building projects
  • Will not rot or break down
  • Environmentally friendly
  • Energy-saving/energy efficient
  • Retains its R and U value even in moist conditions
  • Acts as a thermal barrier to significantly reduce heat loss to the substrate
  • Transforms undertile heating into a very responsive and efficient system
  • Can replace tile and slate underlay
Scope of Use

Marmox Building Products have been appraised (BRANZ Appraisal 895[2018]) for use as an intermediate substrate to tiling for interior areas when applied to timber, plywood, fibre cement or concrete floors.

  • Installed using a flexible tile adhesive in a similar manner to a large tile


  • Walls and floors
  • Partition walls
  • Bath and shower base panels
  • Wash tables and benches
Limitations on Use
  • Not recommended for vinyl
Statement of Building Code Compliance

In the opinion of BRANZ (Appraisal 895[2018]), Marmox Building Products, if designed, used, installed and maintained in accordance with the statements and conditions of this Appraisal, will meet or contribute to meeting the following provisions of the NZBC:

  • Clause B2 DURABILITY: Performance B2.3.1 (b) 15 years and B2.3.2. Marmox Building Products meet these requirements. See Paragraph 9.1
  • Clause E3 INTERNAL MOISTURE: Performance E3.3.3. Marmox Building Products contribute to meeting this requirement. See Paragraphs 12.1-12.4
  • Clause F2 HAZARDOUS BUILDING MATERIALS: Performance F2.3.1. Marmox Building Products meet this requirement
Other Performance Attributes
  • 20 year warranty
BRANZ Appraised
BRANZ Appraised
Marmox Technical Properties
Material Safety Data Sheet


BBA Certificate


BRANZ Appraisal 895: Marmox Building Products

895 [2018] (Amended November 2020)

Installation Instructions
Marmox Brochure

Warmup is an international company providing quality electric underfloor heating solutions to homes and businesses worldwide.

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