Waterproofing Must Knows


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What You Must Know About Waterproofing

Last Updated Mar 28, 2022 · Written by Rob Schneider · 3 min read

Most homeowners don’t think about waterproofing until their home proves to not be waterproof! Then the importance of waterproofing becomes all too apparent. You can try to ignore the dampness that is seeping into the home, but ultimately, that is the most expensive “solution,” since water will ultimately threaten the structural integrity of your home. The best way to prevent rising damp and other problems associated with water is to learn about waterproofing and apply your knowledge where it’s needed. Here’s what you need to know about waterproofing.

Waterproofing is Not for Amateurs

The first thing you need to know about waterproofing is that it is not a job for amateurs. There are many waterproofing products available on the market and many of them are easy enough to apply, but at best, they are “band-aid” solutions. At worst, they can mask the problem without fixing it.

Common places where waterproofing is required include:

Bathrooms, where water is everywhere. The shower must be thoroughly sealed because that is where most water is directed, but anywhere in the bathroom where the walls meet the floor should be professionally waterproofed. Most councils in Australia also require bathroom walls be waterproofed to a height of 1.8 metres.

The laundry room is another water-prone area of the house that should be properly waterproofed.

  • Basements should be waterproofed before they are constructed. If you see signs of rising damp in the basement, don’t just treat the walls with a sealant. That just hides the problem. You’ll need to contact a dampproofing specialist to have the problem taken care of.
  • Rising damp can become a problem on the high side of a sloping property when water becomes dammed against the foundation. Here again, a dampproofing professional is required.
  • Balconies, whether timber or concrete, need to be waterproofed.
  • Your roof needs to be thoroughly waterproof. If water can find its way in, it will find its way in. When it does, it can cause timber rot or electrical problems long before its presence is detected inside the house.

What Happens if You Don’t Waterproof?

Water, where it’s not wanted, is far more than just a nuisance: it can become a real danger. Water rots timber, weakening the timber and eventually rotting it away. This has led to floors and balconies collapsing. Concrete is subject to “concrete cancer” (spalling) and water penetration is the most common cause of concrete cancer. Learn more about How to Deal with Concrete Cancer here on hipages.com.au. Better yet, avoid it altogether by making sure your structural concrete surfaces are thoroughly waterproofed.

Water can be a health hazard, too. Mould and mildew caused by water can trigger allergic reactions and respiratory problems. Some studies have even shown a correlation between mould and depression. Mould and mildew only thrive in moist conditions, so if your house is waterproofed and moisture not allowed to accumulate in the home, they cannot develop.

How to waterproof your bathroom

Last Updated Mar 28, 2022 · Written by Richard Kempthorne · 6 min read

Bathrooms are the major wet area in the house and it is important that the bathroom is correctly waterproofed in order to reduce the risk of structural damage occurring as a result of dampness, water leaks, or condensation.

Requirements for waterproofing bathrooms

The Building Code of Australia and the Australia Standard (AS 3740-2010) outline the minimum requirements for waterproofing in residential bathrooms.  These requirements include:

  1. waterproofing the full floor within the shower recess
  2. at least 100mm over the hob or step down onto the bathroom floor should be waterproofed
  3. at least 150mm up the walls inside the shower walls needs to be waterproofed
  4. the vertical angle between any two walls in the shower needs to be waterproofed up to at least 1800mm high
  5. the entire bathroom floor needs to be waterproofed if it’s timber flooring, plywood or particleboard, or if it is above the ground floor of the house
  1. However, to provide the best insurance against water damage, it is a good idea to go beyond these minimum requirements and ensure that all of the walls within the shower recess are waterproofed as well as the entire bathroom floor. To get a visual on this, see these photos of bathrooms by trade professionals.
  2. Be aware also that some councils will require that waterproofing be done by licensed waterproofing applicators so you should check with your local council before any waterproofing work is undertaken.
  3. The process of waterproofing
  4. It is vitally important that when you undertake a bathroom renovation all the surfaces within the bathroom are correctly prepared and primed.  Especially of importance are any joins between the wall and floor, between the walls themselves, and around any drains in the floor.  Ensure that the surfaces are smooth and free of any loose particles, which may affect the integrity of the waterproofing membrane.  A polyester reinforcement mat should be fitted into all the internal corners of the shower recess, such as the junctions between the wall and floor, the hob and the floor, and the corner formed by two walls meeting.  The waterproofing membrane will then be applied to all surfaces.  Once the first coat has been applied, an hour or two will be required before the second coat can be applied.  The second coat should be applied in a different direction to the first – for example, if the first coat was put on vertically, the second should be horizontal.  Do not use the bathroom until the waterproofing has had a chance to fully cure – this can be as long as five days, depending on your climate.

Tools needed to waterproof a bathroom

  •  Silicone and Silicone Gun
  • Masking Tape
  • Paint scraper
  • Paint roller and tray
  • Paint mixer
  • Spirit level
  • Utility knife
  • Dustpan & brush, broom or vacuum cleaner.

How to waterproof your bathroom step by step guide:

Step 1: How to Waterproof a bathroom

Use a broom. dustpan and brush or a vacuum cleaner to thoroughly clean the floor of any dust and dirt.

Step 2: How to Waterproof a bathroom

The next step to waterproofing your bathroom involves applying the primer.

Transfer the primer to a painters roller tray and use a decent roller to apply it.

Start applying the primer from the back of the room.  Roll it evenly around the bottom half of the wall.  Once you have applied primer to approx. 30 cm from the bottom of the wall you can continue to use the roller to cover the bathroom floor.

Step 3: How to waterproof a bathroom

Once the primer has completely dried you can start thinking about sealing up all of the gaps with silicone.

Firstly remove any old silicone from the areas you are going to seal up.  You can use a paint scraper or a stanley knife or blade.

Take a look at the gaps and then judge what size nozzle you will need to sufficiently fill the gaps with silicone, try placing the nozzle directly onto the space you will be filling.

Once you have determined the size use a stanley knife or a pair of scissors to cut a hole in the tip of the nozzle sufficient enough to create the seal.

Hold the silicone gun at a 45-degree angle.  Then squeeze the trigger whilst simultaneously moving the gun along the line you are sealing up.  It can sometimes help to lick your finger and run it along the silicone you have just applied to smooth it over and tidy it up.

Now let the silicone dry for 24 hours.

Step 4: How to waterproof a bathroom

To help you cut in like a normal painting job you can stick masking tape around the wall.  Place masking tape up to the height you want to waterproof this will help give you a straight edge and will prevent paint from splashing onto areas you don’t want it to.

How to waterproof a bathroom step 5

Applying a waterproofing product is the next stage to completing your bathroom waterproofing project.

To make life easier start applying the waterproofing product in the far back corner of the room.  Again you can use a roller to apply the product. Run the roller around the wall widthways from where the floor meets the wall up to the height of the masking tape you stuck to the wall.

Step 5: How to waterproof a bathroom

The next stage is to add the waterproof membrane.  Find yourself a good quality product.

Take the waterproof membrane sheet and cut lengths to fit the wall and cracks on the floor.

You can use a paint roller or paintbrush to stick the membrane down using the waterproofing product.  Keep doing this until there are no gaps and fully painted over.

Step 7: How to waterproof a bathroom

Once the membrane has been painted over with waterproofing product and dried you can start painting the entire floor.  It typically takes around 24 hours to be completely dry.






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