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ARDEX Internal Tiling System — Over Underfloor Heating

Ideal for internal, heated floors, this ARDEX internal tiling system is designed to withstand long periods of heat cycling from an underfloor hearing system.

ARDEX X 18 is a superior polymer fortified cement-based wall and floor tile adhesive that has been specially formulated with mastic type properties. It contains specially developed fibres that add strength to the tiled area. It has an extended open time, is non-slump and flexible. It is suitable for both internal and external situations including swimming pools.

  • Smoothing Compound: ARDITEX NA
  • Waterproofing: ARDEX WPM 750
  • Tile Adhesive: ARDEX X 18
  • Tile Grout: ARDEX FG 8
  • Silicone: ARDEX SE
Key Features

ARDEX X 18 Key Features:

  • Fibre reinforced for extra strength and peace of mind
  • Excellent workability with low sand content
  • Flexible — achieves S1 classification (S2 with ARDEX E90)
  • Ideal for all tile types including fully vitrified, porcelain and mosaics
  • Non slump — ideal for large format and heavy tiles on floors and walls
  • Extended open time
  • Use over early age concrete/screeds and render
  • For internal and external use Suitable for swimming pools and wet areas.
  • Low VOC content — meets Green Building Council of Australia Green Star IEQ-13 requirements
Scope of Use

ARDEX X 18: 

  • Mix with water to achieve a mortar suitable for internal and external use in residential and commercial applications, including swimming pools. 
  • Over internal undertile cable heating systems
Limitations on Use


  • Do not use over metal or similar substrates
  • ARDEX X18 should not be used on floors with a deflection greater than the joist span divided by 500 for tiles less than 600mm and divided by 700 for greater sized tiles
  • Joist span must comply with AS:1684
  • ARDEX X18 should not be used over substrates subject to shrinkage and other movement e.g. timber, ARDEX provides other systems
Other Performance Attributes
  • ARDEX WPM 750 features Impervashield technology — resists cracking and high resistance to heat
  • Epoxy grout for high performance and high chemical resistance
BRANZ Appraised
BRANZ Appraised
Product info: ARDEX FG 8
Product Info: ARDEX SE
Product Info: ARDEX WPM 750
Product Info: ARDEX X 18
Product Info: ARDEX X 56
BRANZ Appraisal 727: WPM 750 & WPM 1000

727 [2017]

ARDEX Company Profile
ARDITEX NA Video – Substrate Priming and Mixing Procedure

ARDEX New Zealand supply and manufacture a range of quality construction materials, including products for levelling floors; external and internal waterproofing; and fixing natural stone and tiles.

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