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Waterproofing Trafficable Rooftops

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Preparation:

  • 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:

  • Installation shall be in accordance with AS4654.2-2012 Waterproofing membrane systems for exterior use - Above ground level - Design and installation.

  • 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 with clamping ring 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 880 Tanking membrane, ensuring that the first coat has completely dried before applying second coat.

  • WPA 880 Tanking is a chemically modified waterborne flexible waterproof membrane designed for use in demanding external waterproofing applications.

  • Apply Synpave Sports & Rec, ensuring that the first coat has completely dried before applying second coat.

  • SYNPAVE SPORTS & REC is a pre mixed, pre coloured water based, slip - resistant, UV stable coating with excellent performance against wear and weathering.

  • Completely encapsulate parapet walls in primer and membrane. OPTIONAL: Cover membrane on parapet walls with metal capping, ensuring that capping is fixed on vertical surfaces only.

  • Install over-flashing to cover membrane termination along walls. Leave a minimum 10mm gap from finished floor level.

  • Install clamping ring to puddle flange and fit grate.