Skip to main content
Bunnings Warehouse
Lowest Price Policy^
Free delivery* withOnePass_Icon.svg

How to waterproof your bathroom

Room that has just been waterproofed

Overview

Waterproofing is by far the most important part of any bathroom renovation. It is essential to take your time and get it right to avoid water leaks or costly repairs. However, with the right products, expert advice and attention to detail, this D.I.Y. project is easier than you might think. Our handy step-by-step guide will help you get started.

Safety tip: Always wear the appropriate safety equipment (safety glasses, gloves and mask, for example) and always follow the instructions for the product or equipment.

**The regulations around who can do waterproofing differ between Australian states and territories. (In New South Wales and Queensland, for example, you must have a license.) Check the requirements of your state or territory before starting any work.

Steps

  1. 1

    Prepare the area

    Before we begin, we need to make sure that the surface is clean and dry. Once that’s done, measure to 2m up the walls, check it’s all levelled and mask the area. Fill in any gaps and cracks with a suitable repair mortar or flexible sealant and allow to cure.

    Man taping the area  of the wall to be waterproofed. 
  2. 2

    Apply primer

    Next, apply a surface primer with a broom, brush or roller to all areas that are being waterproofed. Start with the walls in the back corner, work your way around and then complete the floor. Once done, allow the primer to dry – this should take about an hour, depending on the chosen product.

    Man applying primer to wall. 
  3. 3

    Bond break joints and corners

    Once the primer is dry, install the bond breaking at all joints. This includes wall-to-wall joints, wall-to-floor joints, construction joints and around any pipes or drains.

    Man applying sealant to joints and corners.
  4. 4

    Secure with reinforcing fabric

    You can simply use a bond breaking sealant or preformed bond breaking corner, tape and pipe sleeves. If using a sealant, use a scraper to flatten the corners and add reinforcing fabric to the areas for extra security. To do this, apply membrane on the surface, and then fabric followed by membrane.

    Man securing edges with reinforcing fabric. 
  5. 5

    Add waterproof membrane

    Now it’s time to apply waterproofing membrane. Make sure your chosen membrane is suitable for bathrooms. Apply the first coat in the same way as the primer coat, ensuring that the layer is approximately 2mm thick. Allow the first coat to dry and then apply the second coat. Waterproofing membranes go on much thicker than regular paint, so just follow the coverage rates for the product and you’ll be safe. Pay particular attention to all corners and joints – this is where most leaks start.

    Once it’s dry, you’ll be ready to tile, screed or over-coat. However, before you do that, check any areas of membrane for cracking or damage. Now is the easiest time to make any fixes!

    Bunnings team member wearing a mask while applying membrane to a wall
  6. 6

    Ready to get started?

    Explore our range of waterproof membranes for your D.I.Y. waterproofing project.

Logo - Workshop - Bunnings Branded - Transparent
Icon - Website - Workshop lightbulbGet InspiredQuestionsAsk QuestionsSpeech bubblesShare Projects
Bunnings Workshop is an online community for D.I.Y. and gardening discussion. Get your questions answered at workshop.bunnings.com.au
link-outJoin the discussion

Get inspired by projects from the Bunnings Workshop community

Health & Safety

Asbestos, lead-based paints and copper chromium arsenic (CCA) treated timber are health hazards you need to look out for when renovating older homes. These substances can easily be disturbed when renovating and exposure to them can cause a range of life-threatening diseases and conditions including cancer. For information on the dangers of asbestos, lead-based paint and CCA treated timber and tips for dealing with these materials contact your local council's Environmental Health Officer or visit our Health & Safety page.

When following our advice in our D.I.Y. videos, make sure you use all equipment, including PPE, safely by following the manufacturer’s instructions. Check that the equipment is suitable for the task and that PPE fits properly. If you are unsure, hire an expert to do the job or talk to a Bunnings Team Member.