Betta Under Tile Membrane

Betta Under Tile Membrane is a liquid rubber developed for wet area waterproofing under tiles, renders and surface finishes. Unique fast curing formulation, allows tiling and finishes to be applied over it after 4 hours once the application is complete. Flexible and elastomeric, Under Tile Membrane forms a durable water vapour barrier against permanent wet conditions. Compatible with a range of tile adhesives, renders and topping compounds.

When used with the Betta detailing range the system complies with all relevant Australian wet area standards including AS/NZ 4858: 2004, and AS 3740 2004

1L, 4L, & 15L


  • Water based, non toxic and non flammable
  • Fast cure, allows tiling over after 4 hours
  • User friendly and environmentally safe
  • Withstands continuously wet conditions
  • Flexible and elastomeric
  • Compatible with tile toppings and various surface finishes
  • Complies to AS/NZ 4858 and AS 3740 as a class III membrane
  • Excellent vapour barrier properties



  • Wet areas, showers and tiled areas
  • Balconies, decks, podiums, terrace floors
  • Roofs to be covered over with screeds and toppings
  • Sandwiching between existing and new concrete substrates
  • Retaining walls, planters and garden beds
  • Liquid vapour barrier between toppings and slabs
  • Anti fracture membrane for floor tiling and hairline cracks

Surfaces must be prepared thoroughly before commencing application. All substrates must be structurally sound, stable, dry, and clean, Smooth shiny surfaces to be roughened or etched. Rough surfaces are to be evened or filled first. Building surfaces must be constructed to manufacturer’s recommendations and relevant building standards in force at time of membrane application. All surfaces are to be free of sharp protruding surfaces, loose material, de-bonded coatings, curing membranes/agents, release agents, wax residues, foreign particles, laitance, algae and moss, grime, oils, animal fats or grease remains.

Structurally unsound layers and surface contaminants are to be mechanically removed by abrasive blasting, blast tracking, grinding or equivalent methods.

Primer: Select appropriate primer if required and apply according to the primers instructions.

  • Betta Prep Coat Primer – for general porous vertical and horizontal building surfaces. Brush or roller apply primer to total surface area at a minimum coverage of 1 litre per 6m2 and allow drying for 30 minutes or once wet film dries to a clear transparent coating
  • Betta Super Primer – for non porous, smooth and dense surfaces. Brush or roller apply primer to total surface area at a minimum coverage of 1 litre per 10m2 and allow to dry for 1 hour
  • Betta Damp Stop – for surfaces with residual or rising damp. Apply by brush or roller in 1-2 coats at a minimum coverage of 1litre per 8m2 per coat. Allow to dry for a minimum 24 hours before applying membrane. Primer must be tack free before applying membrane.


Install a bond breaker system such as Betta Joint Band, Reinforcing Fabric and Waterproof Corners. This is a requirement to meet AS 3740 Australian Waterproofing Standards

Once the Elastic Joint Band is in place, apply Betta Under Tile Membrane to the total floor area and to walls at 150mm high in general wet areas and balcony decks, and at 1.8m high in shower alcoves. A continuous seamless membrane should be the final finish to the total area upon completion of the waterproofing membrane application.

A minimum of 2 coats is to be applied at a total minimum coverage of 1.5 Litre/m2, forming a dried film thickness of approx 1.2mm. For vertical or pitched applications, coverage of 1Litre/m2 can be considered. Apply subsequent coats at different directions to the previous coat. Apply by roller, brush or spray unit

  • Tack Free  – 45mins
  • Recoat – 1 hour
  • Dry Film  – 4 hours
  • Tiling or toppings over – 4 hours
  • Flood testing  – 16 hours


  • Based on normal ambient conditions of 20oC, 50% RH.
  • Temperature, humidity and porosity will vary dry times.
  • Note – Once dried, ensure surface is wiped clean before tiling to remove any residues


  • Only polymer modified cement based adhesives are to be used for tiling over Betta Under Tile Membrane
  • Pre mixed tile adhesives are not recommended
Areas OF USE
  • Do not apply outside when rain is imminent
  • Do not apply to surface temperatures below 5°C or above 35°C
  • Not to be used in areas where solvent or petroleum based products may be spilled
  • In areas subject to negative pressure or rising damp, first treat with Betta Damp Stop primer
  • Finish toppings must be water based and solvent free
  • Allow 10 days drying if treated area is to be flood tested
  • Before commencing the application, adhesion of products to be used (primers, membranes, coatings) should be tested over a typical area of the prepared surface to ensure satisfactory adhesion
  • Not suitable for exposed areas, must be finished with topping or tiles




Unit 2, 115 Belmont Avenue
Belmont 6104
Western Australia

Phone: (08) 6272 3800
Fax: (08) 9277 4068