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Waterproofing Retaining Walls (on footing)




  • 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, masonry surfaces must be pointed flush and surface defects repaired. New concrete must be cured for minimum 28 days.

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



  • Repair all surface defects on retaining wall masonry surfaces with Aftek Penapatch HB80. Penapatch Structural HB80 is a high strength; high build shrinkage compensated structural repair mortar.

  • Install a 40mm x 40 mm fillet to the internal corner of wall and footing using Aftek Penapatch HB80. Preferably extend fillet to outside edge of footing to prevent pooling of water.

  • Install a gun-able water stop around all penetrations. The water stop must be packed in between at least a 50 mm cover of Aftek Penapatch HB80. Gun-able water stop products are caulk grade (gun-able), single component swelling pastes used to stop water infiltration through concrete construction joints.

  • Prime retaining wall, PVC and metal pipes using Soprema Elastocol Stick. Elastocol Stick is a primer designed to enhance the adhesion of self-adhesive membranes on porous surfaces.

  • Install a 200 mm wide reinforcement layer of Soprema Colphene 3000 over fillets. Colphene 3000 is a self-adhesive waterproofing membrane composed of SBS modified bitumen and a tri-laminated woven polyethylene.

  • Install Colphene 3000 to Retaining Wall.

  • Lap Colphene 3000 onto penetrations, then flash with Alsan Flashing. Alsan Flashing is a waterproofing one-component polyurethane / bitumen resin.

  • Install Aluminium pressure seal at top of wall. Flash with Sopramastic in order to terminate membrane. Sopramastic is a black, solvent-based mastic containing SBS modified bitumen, fibres and mineral fillers.

  • Install Newton 408 EcoDrain to all waterproofed surfaces. Newton 408 EcoDrain is a two-core drainage sheet consisting of a non-woven geotextile filter layer, thermally welded to a water impermeable HDPE (High Density Polyethylene) drainage membrane.

  • Install slotted drainage pipe wrapped in Geotextile next to footing and below fillet level.

  • Cover drainage pipe with a minimum of 300 minimum of gravel and surround gravel with additional Geotextile filter.

  • Backfill soil.