How to waterproof under tiles

Download the full detailed instructions as a PDF document.


Before you start

Before you start your waterproofing project it is important to get an understanding from your local government requirements and AS3740 for waterproofing in wet areas prior to carrying out a waterproofing project. The minimum requirements are as follows:

  • Full floor within shower recess.
  • Minimum 100mm over hob and onto the bathroom floor.
  • Minimum 150mm up walls within shower recess.
  • The wall to wall junction(s) within shower up to a minimum height of 1800mm or 80mm above shower rose.
  • The full bathroom floor if it is made from timber, plywood or particleboard or if it is above ground floor or if it has a floor waste.

Application

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Step 1:

Ensure surfaces are sound and dry and floor sheeting materials are installed to manufacturer’s instructions. Remove all contaminating materials such as dirt, oil, paint and any cured material. Prime all areas to be waterproofed with Dunlop Primer & Additive according to instructions. AAC Blocks will require 2 coats of primer.

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Step 2:

Apply a generous bead of silicone to all cracks and floor/wall junctions with a neutral cure silicone.

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Step 3:

Prepare Dunlop Reinforcing Matt by cutting to size.

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Step 4:

Apply the first coat of Dunlop Undertile Waterproofing with a clean paint brush or roller so that surfaces to be waterproofed are completely covered with a generous coat.

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Step 5:

While the first coat is still wet, install the Dunlop Reinforcing Mat in all wall/floor junctions, cracks and over the shower hob.

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Step 6:

Remove wrinkles in the mat and ensure the mat is fully wetted with no dry areas. Immediately apply a second coat of Dunlop Undertile Waterproofing. In areas where no mat has been used, allow 4 hours drying time before applying second coat.

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Step 7:

Prime crack and apply a bead of silicone along crack areas.

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Step 8:

The membrane should be 1mm thick on floors after 2 coats or 0.5mm thick on walls after 2 coats (dry film thickness).


Handy Hints

  • Your local government has waterproofing requirements as well as the National Construction Code for Tilings standards.
  • Allow up to 48 hours for waterproofing membrane to dry thoroughly before commencing tiling. Drying time will depend on temperature and humidity. The following Dunlop Tile Adhesives are suitable to use over Dunlop Undertile Waterproofing: Dunlop Wall & Floor Tile Adhesive, Dunlop Tile-All, Dunlop Trade Resaflex, Dunlop Universal Tile Adhesive, Dunlop Multipurpose Mastic Tile Adhesive, Dunlop Premixed Mastic Tile Adhesive and Dunlop Super Tileset.
  • To complete your tiling project, use Dunlop Coloured Grout that complements your tiles as well as the matching Dunlop Coloured Silicone. Grout joints can be sealed with Dunlop Grout Sealer.
  • What you will need: Dunlop Undertile Waterproofing, Dunlop Primer and Additive, Dunlop Reinforcing Mat, Neutral Cure Silicone, Paint Brush or Roller and Caulking gun (for silicone)
  • For Shower waterproofing try our Dunlop Shower Waterproofing Kit for easy project completion of your bathroom waterproofing project.