Everflex WPM Class III Under-Tile Waterproofing Membrane

Everflex WPM is a Class III liquid waterproofing membrane for bathrooms, showers, balconies and decks where the finished membrane will be protected by tile, screed or another approved finish. Its highly flexible, seamless film is intended for internal and external under-tile waterproofing systems.

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Best fit in the Everflex range

Choose WPM when the project or system specification calls for Everflex WPM and the membrane will sit beneath tile, screed or another protective finish. Aqua-Ban is the SBR, anti-microbial under-tile option in the same range and publishes a very similar Class III under-tile performance envelope; do not substitute one for the other without checking the project requirements. For exposed UV applications, move to Everflex WPUV or Everflex HVUV.

How it works

Everflex WPM Elastomeric Waterproof Membrane is a single-component, water-based liquid membrane reinforced with microfibres. It cures to form a fully bonded, seamless barrier that resists water immersion without re-emulsifying. It has a Class III elongation rating of 391% under AS 4858, which provides the high elasticity needed to accommodate structural movement on timber floors and joint connections without cracking. The formulation is low-permeability, non-toxic, contains less than 1g/L VOCs to meet Green Star environmental criteria, and actively inhibits mould and biological growth.

Numbers that matter

• 391% elongation: Tested to AS 4858 as Class III high flexibility to withstand joint movement.
• 1.0mm minimum DFT: The minimum dry film thickness required for internal installations to ensure waterproofing integrity.
• 1.3mm minimum DFT: The required dry film thickness for external installations such as balconies and decks.
• 48-hour cure time: The minimum drying period required at 25°C and 50% relative humidity before tiling can commence.
• 0.75% water absorption: Tested to AS 3558.1 to verify low absorption performance when fully immersed.

Where to use it

Suitable for internal and external under-tile applications over the following substrates:

• Concrete cured for a minimum of 28 days.
• 3:1 sand cement screeds or Gripset C-Bed.
• Masonry and cement render cured for at least 4 days.
• Cement sheeting, underlay, external weatherboard, and blue board.
• Pre-cast concrete once all release agents are completely removed.
• Wet area plasterboard and Villaboard.
• Timber flooring, including structural plywood Type A (PAA JAS-ANZ).
• Brickwork and Hebel aggregate blocks.

Installation and film thickness

All substrates must be dry, clean, and free of dust, oils, grease, curing compounds, or release agents. Non-structural cracks, holes, and deformities must be rectified before application.

The use of a primer is always recommended. Use Everflex WBP for internal areas. For external roof decks and balconies, use Everflex VBS. Apply the primer, and once touch-dry, apply the membrane within 2 to 24 hours.

Mix Everflex WPM thoroughly before use. Apply in a minimum of two coats using a brush or roller. Apply the first coat at approximately 0.75mm wet film thickness (WFT). Once dry, apply the second coat at a right angle to the first at 0.75mm WFT. Verify the thickness during application with a wet film thickness gauge. For internal areas, a minimum of two coats must achieve a 1mm dry film thickness (DFT), typically requiring 1.5 litres per square metre. For external applications, a minimum of two coats must achieve a 1.3mm DFT. Recoat window is 2 to 4 hours after touch-dry and within 24 hours at 25°C and 50% humidity.

Detailing and joints

• Gaps and joints: Everflex WPM cannot span gaps. Apply a sealant fillet using Adheseal PU, Hi-Flex MS, or a suitable bond breaker to internal corners and sheet joints. For dynamic cracks, expansion joints, and control joints, use Adheseal Elastoband or Butyl Tape systems. Polyester reinforcing fabric can be embedded into the first coat if required.
• Waste outlets: Rebate floor wastes and puddle flanges into the floor. Seal all perimeters and gaps with Adheseal PU or Hi-Flex MS sealant.
• Waterstops: Secure and seal exterior door barriers, plastic corner angles, and waterstops using Adheseal PU or Hi-Flex MS sealant.
• Tile adhesive compatibility: Suitable for use with solvent-free tile adhesives. RLA and Gripset have confirmed compatibility for C-Lite, C-Mastic, Unigrip, and Mastic adhesives over the cured membrane.

Limitations

• Do not apply if the temperature is below 10°C or above 35°C.
• Do not apply on damp, wet, or contaminated substrates, or if rain is imminent.
• Not designed for long-term UV exposure; the membrane has limited UV resistance and must be tiled or topped. It is not suitable as an exposed membrane.
• Not suitable for areas subject to rising damp or negative hydrostatic pressure.
• Not formulated to tolerate foot traffic before tiling.
• Clean tools and wet spills immediately with water; cured membrane must be removed by mechanical means.