Waterproofing Bathroom

Waterproofing is one of the first steps taken when a bathroom is under construction, and it involves installation of a waterproofing membrane on the walls and floor of the bathroom, to protect them from water ingress and damage.

Benefits of waterproofing the bathroom

  • To prevent water penetrating through the walls and floor - the bathroom is the wettest room in the house, which means that water is constantly in use, it can cause damage to other areas of a house if not well taken care of, therefore waterproofing is essential. The aim is to ensure water cannot leave the wet area and is directed to the drains or floor wastes.

  • Design Flexibility – you can have a bathroom anywhere, as long as it is waterproofed. Upstairs, downstairs, in your room, etc., this gives you freedom of where your bathroom is located.

  • Prevent damp and mold and the associated negative health problems - these are caused by water, hence a waterproofed bathroom is necessary.

A step by step guide to waterproof your bathroom

You shall need the following;


  • Cleaning equipment (Floor Scraper, Broom).

  • Spirit Level.

  • Tape Measure.

  • Knife.

  • Caulking gun.

  • Paintbrush and paint roller.

  • Safety equipment.

  • Spatulas & Caulking Tools.

  • Spirit level.


  • Polyurethane Sealant or Neutral cure Silicone.

  • Waterproofing Bandage.

  • Primer.

  • Waterproofing membrane.

  • Aluminium and or PVC Angles.

Step 1: Before you begin, ensure that your floor is clean by removing any loose material with a floor scraper. Clear any dirt or dust from the bathroom using a broom and dustpan.

Step 2: Apply primer to the shower wall, floor and vanity areas.

Step 3: Once the primer is dry, Using a caulking gun apply silicone or polyurethane sealant to all the gaps between the wall a floor and all other areas with gaps. Using a caulking tool create a cove of approximately 25mm, and remove any excess sealant.

Step 4: Install shower and door angles with sealant ensuring they are level with a spirit level. Typical door angles are aluminium and to a height of 40mm. Typical shower angles are PVC and are of a height of 70mm. This is later cut down to a height of 10mm above the finish tile height and shower screen installed over the top.

Step 5: Using a brush, cut in the room with the waterproofing membrane. cut square sections of bandage and then cut out holes to the desired size of tap mixers and roses, using the membrane to saturate and create a seal onto the fittings. Once the corners of the shower and wall/floor joints are cut in apply the waterproofing membrane using a roller, first on the walls, then the floor as you leave the room.

Step 6: Allow membrane to dry for 24 hours and apply a second coat to the area.


Waterproofing is a simple yet very important process that should be carried out by a professional. Something as simple as choosing non compatible products can have huge implications and cost you a fortune to repair.

Furthermore, waterproofing contractors can get better quality products at much lower prices than the general public and have relationships with manufacturers should there be any issues with the product or changes in specifications.

Often for not much more than you can buy the product alone yourself, you can have a waterproofing contractor supply and install waterproofing with a manufacturer's warranty and workmanship guarantee and you can rest assured the job is done properly.


Click to call for your FREE waterproofing quote