How to Waterproof a Shower Using the Mapei Waterproofing Kit

If your next project involves installing a shower and making sure it’s totally waterproof, then my post today should help you to achieve it. We recommend using the Mapei Shower Proofing Kit to make the job a lot easier and following the steps below will ensure a totally water-proof area that should last for many years.


The kit contains everything you need in a single tub to prevent any costly leaks from your shower area, offering you peace of mind if you are tiling in a shower cubical area or a shower over the bath. It covers approximately 4 square meters and really, should be considering an essential requirement for bathroom tiling.

What You’ll Receive in Your Kit:

5kg of Mapegum WPS Liquid Waterproofing membrane

This fast-drying liquid membrane is for the interior waterproofing of the bathroom and shower walls as well as the countertops before installing ceramic tiles.

10m of MAPEI Waterproofing Tape

This tape is used to reinforce corners & junctions and for waterproofing systems formed using liquid membrane.  (Please note that joints between pieces of MAPEBAND PE 120 must also be bonded using MAPEGUM WPS.)

0.5kg of Waterproofing Primer

This pre-diluted water based synthetic resin primer is used to prepare plaster/plasterboard substrates prior to installing ceramic tiles or stone material and cementitious adhesives.


How To Ensure Your Shower is Completely Watertight

  • Fill in any cracks or voids in the substrate with a suitable filler. Do not use the MAPEGUM WPS to fill voids or even out surface irregularities.
  • Do not apply the products at less than 5°C.
  • Prime all porous substrates and gypsum plaster with the pre-diluted shower waterproofing kit primer and allow to dry. Do not add any additional water to the primer.
  • Mapei Waterproofing Tape is required to form an elastic reinforcement at the following locations: internal wall angles and board joints, around pipe penetrations and at junctions between wall and bath or shower tray.
  • Carefully cut the Mapei Waterproof Tape to the correct size using a sharp knife or scissors.
  • Thoroughly degrease the edges to be waterproofed with a suitable solvent such as acetone. Lightly abrade the contract area and wipe again with the solvent. Do not prime the GRP surfaces.
  • Using a brush, apply a narrow strip of Mapei Mapegum WPS (slightly wider than the Mapei Waterproof Tape) to the areas listed above (including shower trays and bases).
  • Cut the scrim edge from the Waterproof Tape leaving the grey rubber centre. Ensure that the water proof tape sits on the shower base and cut the outermost edge. Make sure it doesn’t protrude beyond the thickness of the tiled finish and its adhesive bed.
  • Whilst the coating is still wet, push the Mapei Waterproof Tape firmly into position in these areas. Ensure that no air voids are trapped beneath the Waterproof Tape and that it lays flat with no folds. Pay special attention to the three way angle where the two walls meet at the base.
  • Using a brush or roller, apply an even coat of Mapegum WPS to the walls and then to the floors. Allow the membrane to dry for approximately 1 to 2 hours then apply a second coat to all areas. The ideal dry film thickness is between 1mm and 2mm.
  • Tiles may be fixed using a suitable Mapei adhesive from 24 hours after application of the waterproof membrane.
  • Grout and then finish with MAPESIL AC silicone sealant.

And that’s it! Your shower is now fully waterproof. Of course, our reps are always on hand to answer any further questions you may have.

Mapei Waterproofing Kit deals.

As a multi-award winning interior design content creator, Kimberly Duran is an Interior Design-obsessed American ex-pat, who chronicles her decorating journey and dispenses interior design advice in her personal blog, Swoon Worthy. When she’s not helplessly drooling over all the latest trends in design, she’s adding things to the imaginary ‘shopping basket’ in her head, she likes to get messy tackling DIY projects with her partner in crime, Wayne, stalking eBay for vintage bargains and filling her home with her favourite neutral – gold.