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Waterproofing Tiled Rooftops and Podiums




  • All surfaces to be waterproofed must be firm, clean, dry, sound and smooth. All grease, oil, wax, curing compounds, loose material, paint and any other contaminants must be removed, surfaces must be pointed flush and surface defects repaired.

  • External corners to be waterproofed must be bevelled to ensure a smooth transition of membrane from vertical to horizontal surfaces.


  • Installation shall be in accordance with AS4654.2-2012 Waterproofing membrane systems for exterior use - Above ground level - Design and installation. Tile installation shall be in accordance with AS 3958.1-2007 Ceramic tiles - Guide to the installation of ceramic tiles.

  • The base of the roof shall be graded with a minimum of 1 : 100 fall to floor wastes. If required, form the required falls by installing CTA Eco Screed mixed with Efflock over the substrate. NOTE: Falls must be in the substrate to be waterproofed. Screed must be installed prior to installation of primer and membrane. CTA ECO SCREED is a pre blended screed underlayment consisting of graded sand, cement and additives. EFFLOCK is a high performance, solvent free, water based liquid additive, ideal for the bulk impregnation of cementitious building materials.

  • Install 12 mm fillet/bond breaker to internal corners using Admil SupaSeal PU.

  • Admil SupaSeal PU is a Low Modulus, Hybrid Polyurethane, flexible joint sealant and adhesive that is free of Isocyanates and other hazardous raw materials and omits low odour.

  • Prime PVC and/or metal substrates using WPA 160.

  • WPA 160 is a specialised solvent free primer designed for enhancing the adhesion of subsequent membranes, adhesives, toppings and decorative finishes over porous or non-porous substrates.

  • Install puddle flange to floor wastes. Puddle flange must be recessed.

  • Apply WPA 460 Primer to substrate to be waterproofed. WPA460 is a two component water based epoxy primer used to seal concrete and masonry surfaces.

  • Apply WPA 500 or WPA 230 UV membrane, ensuring that the first coat has completely dried before applying second coat. WPA 500 is a waterborne, fibre reinforced, flexible waterproof membrane designed for use under tile finishes. WPA 230 UV is an elastomeric, one part, fibre reinforced, UV stable, water based polyurethane membrane.

  • Once membrane has completely cured, install tiles using CTA Promaxset or CTA Pro Premium. PROHESIVE PRO PREMIUM is a premium quality, extremely high strength, polymer modified, cement based adhesive. PROHESIVE PPROMAXSET is a high strength, polymer modified, flexible cement based adhesive, which has been specially developed for installing most types of tiles.

  • Grout tiles using the appropriate colour of CTA Polyblend Grout. POLYBLEND grout is a premium high quality polymer modified, flexible, cement based, coloured grout designed for grouting most types of tiles including ceramic, porcelain, natural stone and glass mosaics.

  • Install backing rod to all perimeter and intermediate movement joints and seal with silicon or polyurethane sealant.