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A person painting over a membrane sheet on a bathroom wall

Overview

Applying a waterproof barrier is an essential part of preparing to install a shower. We'll teach you how to apply the waterproofing and reinforce the joins and gaps in the walls and floor. You will also learn how to prepare and reinforce your surfaces properly. 

Steps

1Mark out the area to waterproof around the shower

Measure up your wall and mark out where you'll be waterproofing. Then mask those lines off with masking tape. A good rule of thumb is to extend your waterproofing 100mm above your water outlet and 100mm wider than the edges of your shower. But check your local council regulations to make sure what is required.
A person applying masking tape to a bathroom wall

2Prepare to waterproof the shower

Use a brush to paint primer onto the area you want to waterproof. Use a generous amount on every surface. While you're waiting for the primer to dry, measure the edges, corners and internal joints that need to be waterproofed. Now cut lengths of the reinforcing membrane to cover these areas.
A person painting primer onto a bathroom wall

3Waterproof the shower walls

Paint a coat of waterproofing where your reinforcing membrane will be installed. Then put the membrane on the still wet area. Now apply another coat over the top, flattening the membrane with your brush as you go. To make it easier when putting membrane into recessed corners, cut a nick that lets it split across the different surfaces. Once the membrane is installed, use horizontal strokes to paint a first coat of waterproofing across the walls.
A person painting over a membrane sheet on a bathroom wall

4Waterproof the shower floor

Install reinforcing membrane where the floor joins the walls and around the drain. Once again, paint the area, then put the membrane down and give it a second coat to flatten it. When your membrane is installed, waterproof the rest of the floor. Once the first coat has dried, give the whole shower cavity a second coat, this time using vertical strokes instead of horizontal ones on the walls.
A person painting over a membrane sheet where the bathroom wall meets the floor

Suggested products

More D.I.Y. Advice

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.