Waterproofing a shower is a process of covering the area with a hydrophobic membrane that will create a barrier between the moisture and your walls or floors. This membrane can come in thin sheets or as a spray-on application. The membrane is made from waterproof material such as plastic, rubber, extruded polystyrene foam, coated fabric, or petroleum-based asphalt.
Waterproofing is your primary defence against leaks. Leaking water can cause major structural damage in your wall frames, joists and sub flooring. Penetrating water can be devastating for a home. It is also likely to lead to rising damp, mould, mildew, crumbling tile grout, and stains. While there are some treatments you can apply to try and minimize the damage done by poor waterproofing (such as a chemical injection cream), this will be very expensive, time consuming and complicated. It is much better to avoid such problems altogether – and the process is fairly simple.
How to waterproof a shower: DIY bathroom waterproofing
Waterproofing showers is a task that the average DIY-er could attempt. However, it’s best to bear in mind the disastrous consequences should the waterproofing be done incorrectly – if you are unsure about your ability to undertake this task, it is better to play it safe and hire professionals rather than pay the price years later. Be sure to keep the HIA Waterproofing Standards in mind to ensure that your renovation is up to code.
Planning the project is very important. This means researching and deciding on products, budget, and timeframe. It will also include measuring your shower and finding a corresponding product for the size. Generally speaking, you want to have double the litres to shower size, so a 4-litre kit would treat a 2 wall shower and a 6 litre kit would treat a 3 litre shower. Be aware that extra complications like installing a waterproof window in shower or navigating around taps may require detailed planning.
You will also need to plan the waterproofing in accordance with your local council guidelines. These vary all across Australia, so you will have to be vigilant. The average expectation for waterproofing is that the waterproof area should be extended 100mm above the faucet/water outlet, and 100m wider than the edges of your shower. This is to account for splashing and the risk of water vapour seeping into walls over time. However, your council may require a greater waterproofed area size – be sure to check beforehand.
Waterproofing a shower niche: A step-by-step guide
Step 1: tools and materials
The first step to any project is acquiring the right equipment. For a DIY tile shower waterproofing job, you will need:
- Bucket
- Scissors
- Pencil
- Masking waterproof tape
- Safety glasses
- Rubber gloves
- Paint brush, roller and tray
- Spirit level
- Silicone
- Sealer
- Primer
- Waterproofing membrane and/or waterproof paint
- Reinforcing membrane
Note that some waterproofing kits will include most of the materials in bulk – and often the tools as well. For example, the Crommelin Shower Waterproofing Kit includes everything you need to waterproof a shower, with no additional purchases required.
Step 2: Measure and mark the area
Find out your local council regulations and make sure that your waterproofing area is the right size. Usually this means leaving 100mm extra waterproofing above the water outlet and on either side of the shower. Mark the area with masking tape once you have measured it out.
Step 3: Prepare the area
Using your paint brush, coat the area that you want to waterproof with a generous amount of primer. Leave it to dry. While the primer dries you should measure the corners, edges and internal joints of the shower. Cut lengths of the reinforcing membrane into pieces that will fit over these areas.
Step 4: Reinforcing membrane on the walls and corners
Now you should paint a layer of the waterproof coating where your reinforcing membrane will be installed on the walls and corners. While it is still wet, place the reinforcing membrane over the top. For recessed corners, you may need to cut a nick in the reinforcing membrane.
It will need another coat of the waterproofing over the top once the reinforcing membrane has been put in place. You should flatten the membrane with your brush while painting for a smoother look.
Step 5: Waterproof shower walls
Once you have installed the reinforcing membrane, you can turn your attention to the rest of the shower. Coat the walls with the waterproofing using even, horizontal strokes.
Step 6: Reinforcing membrane on the floor and drain
Now it’s time to install reinforcing membrane where the floor joins the walls, as well as around the drain. Paint the area, place the membrane down, and coat over it to flatten it.
Step 7: Waterproofing shower base
After the reinforcing membrane has been installed, you can waterproof the rest of the shower floor. You should do this using the same horizontal strokes as you did for the walls. If you have a large or walk in shower, start at the far end and work your way backwards to the front of the shower, so that you do not have to step on your own work as you go.
Step 8: Second coat of shower water barrier
Once you have allowed everything to dry – which will take at least 2 hours - it is time for a second coat. This coat should be applied vertically instead of horizontally like the last one. This is important to making sure that the coverage is even.
You may be tempted to skip the second coat and build-up the coating thickness on the first go. However, this is ineffective and could lead to uneven waterproofing which will create problems down the line. Most waterproof membranes are 2-4mm thick, formed by 2 coats applied at 90 degree angles.
Step 9: Tile over
Once you have waited 48 hours for the second coat to dry, you can install your shower flooring and wall coverage (usually this will be tile).
Step 10: Decorate and enjoy!
Place your home décor items like a shower curtain, cabinets and mirrors and take a shower in your brand-new waterproofed bathroom.
