WP130 Waterproofing Retaining Walls – Negative Application


  1. 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 a minimum of 28 days.
  2. External corners to be waterproofed must be bevelled to ensure a smooth transition of membrane from vertical to horizontal surfaces.


  1. If the area to be waterproofed is subject to continuous water seepage, seal off the flow using Mapei Lamposilex Waterstop.

    Mapei Lamposilex Waterstop is an ultra-fast setting and curing hydraulic binder for stopping water leaks. When mixed with water, Lamposilex produces a paste with a plastic-thixotropic consistency easy to apply even on vertical surfaces, with no need for formwork.

  2. Repair all surface defects in concrete footing with Aftek Penapatch Structural HB80.

    Aftek Penapatch Structural HB80 is a high strength; high build shrinkage compensated structural repair mortar.

  3. Install an appropriate cove to all vertical and horizontal internal corners using Afftek Penapatch Structural HB80.
  4. Install a Gunnable Waterstop around all penetrations. The waterstop must be packed in between at least a 50mm cover of Aftek Penapatch Structural HB80. Gunnable waterstop products are caulk-grade, single-component swelling pastes used to stop water infiltration through concrete construction joints.
  5. Prime PVC and other non-porous substrates using WPA 160 primer.

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

  6. Install a reinforcing layer over all coves using WPA 100 membrane, with WPA Fibreglass Mesh embedded into the membrane reinforcing layer.

    WPA 100 is a single-component, fibre-reinforced, rapid-drying, cementitious waterproofing membrane.

    WPA Fibreglass Mesh is an alkali-resistant fibreglass mesh used in reinforcing protective waterproofing compounds, anti-fracture membranes and insulating materials.

  7. Install three coats of WPA 100 membrane to achieve a minimum 3mm dry film thickness. Ensure that the previous coat has completely dried before applying the subsequent coat(s). NOTE: All penetrations must be waterproofed.

Products Used

  • Mapei Lamposilex Waterstop
  • Aftek Penapatch Structural HB80
  • WPA 160
  • WPA 100
  • WPA Fiberglass Mesh