Different Types of Commercial Waterproofing

30 August 2022
By Elizabeth

If you think that because a building is made from concrete and measures have been taken to protect it that it will thus be impervious to water, you may need to think again. Protecting a building from water is something that people often take for granted. They think concrete structures are impervious to water, but sadly, they are not. Chemicals and minerals which help give the concrete its strength can also be the proponents which react with chemicals in water and other liquids which ultimately lead to concrete spalling.

With Sydney (and much of the East Coast of Australia) set to record its wettest year on record (per the Sydney Morning Herald)  the need to not only protect your building, but understand what may affect it, is higher than ever.

What you may not realise

In our last blog we spoke about the effect of water and other factors on the foundations of a building. You may believe that your building has adequate drainage to prevent the build-up of water, drain it and thus minimise the chance of impact on your foundations. And sure, whilst this is a factor you should keep your eye on, did you know that most waterproofing issues we are called to inspect are to the flat roof areas and the decks which sit above car parks? If these spaces are above residential spaces such as in an apartment, the impacts are real and tangible for those residents underneath. After all, who wants to live in a leaky building.

Similarly, whilst people may not live in a commercial building, where the leaks affect the tenants below, the impacts are often financial and a pain for the owners who need to put into place special WHS procedures to minimise the risk of slips, cordon off areas of risk and then undertake repairs with minimal impact on occupants.

In this article today, we want to provide you with an overview of different issues caused by water and then provide insights into the different methodologies/options available to you for the protection of those areas subjected to water.

The problem with water in structures

In most parts of Australia – at least those areas which have multiple large buildings – rain is a pretty common occurrence, and sadly, so too, are water leaks. Though buildings are designed to be beautiful and functional (irrespective of whether that function is to provide housing, or to provide spaces for offices) the impacts of poor workmanship, faulty products, the elements and general wear and tear mean that what was once designed to be protective can now be a problem. That is, flat spaces often become an area where water leaches into cracks and into the spaces below. The impacts of this water ingress can be both visual and structural:

  • A rise in the mold living and work spaces
  • Damage to structural timbers
  • Damage to mechanical elements such as lifts or air conditioning
  • Collapsed plasterboard ceilings
  • Expensive repair work
  • Damaged carpets
  • Corrosion of structural steel which causes concrete cancer, which in turn exacerbates and accelerates the issues
  • Damage to furniture, carpets, electrical elements and so on.

Ultimately, and most seriously, however, the primary concern with water leaks is the impacts it can have on the strength and integrity of structural materials elements used in construction. These seemingly innocuous drips of water can ultimately have large and expensive consequences.

Addressing structural issues with commercial waterproofing

For the purposes of preventing water from getting into places, it shouldn’t in the first place, a number of purpose-built waterproof products will have been installed during construction. However, let’s fast forward to the time where you are aware there is a problem, have identified where it is (which is a harder task than it may seem) and rectification needs to be undertaken.

The most common types of commercial waterproofing include cementitious waterproofing,  liquid waterproofing and bitumen-based solutions. But what are they and which is best?

Cementitious Waterproofing

The first option is undoubtedly the most easy to apply (and can be applied by most “handy” trades) albeit it is the least suitable. This solution is basically the application of a cement coating that is applied to cracked areas on walls, terraces, and flooring surfaces. The cement dries hard and effectively plugs the area of cracking. Yet, because it dries hard it has no ability to contract and expand with temperature fluctuations meaning, over time, it will be ineffective, and the problem will resurface.

Liquid Waterproofing

Liquid waterproofing, on the other hand, is generally a more reliable solution. When applied, the liquid transforms into a rubbery coating, which sets directly onto the structure, providing a high level of flexibility. Designed with UV resistance, this solution is more expensive, however, its ability to flow into areas which are hard to reach make it a great all-round solution. One such type of liquid membrane is polyurethane waterproofing. This highly versatile product can be applied to flat roof substrates, such as concrete, cement mortar, terrazzo, and other cleaned surfaces. It has excellent adhesion to these substrates, is high flexibility, has high resistance to weathering, and as stated good UV resistance.

Best of all, as it can be built up in certain areas, it can be used to address falls to ensure that water moves away from problem areas and towards drains.

PVC Membranes

PVC membranes are a thermostatic sheet membrane that is laid over a surface to achieve a water-tight surface. In essence, the PVC-based sheet is one continuous layer that is applied to a surface using minimal additional components. There are two options:

  • A fully adhered system that is bonded to the deck using a specific PVC bonded adhesive. It offers great water protection and is good for high wind areas
  • A mechanically attached system that uses fasteners that are holt-welded to the surface to pin the PVC to the deck.

Torch on Membranes

One further alternative is the class of membranes known as Torch-on membranes and waterproof wraps. Made with a unique blend of polymers and high-quality bitumen mix, they are used for waterproofing in what is ultimately labour intensive, but highly effective at keeping out water. Torch-on membranes are rolled out on the application area with a slight overlap on the preceding roll. As the sheet nears the surface it is heated with a hand-held propane torch which melts the bitumen and adheres it to the surface. This melting process means the seams are melted together creating a waterproof seal. As bitumen is highly elastic it can expand and contract without cracking or melting and has a high tolerance for both cold and heat. One last advantage is that the top of the membrane can be coated with aggregate to achieve a non-slip rating which is suitable for the area it is applied to.

Commercial Waterproofing with Remedial

Waterproofing application is only one piece of the puzzle. Whilst it may be the most time-consuming part to rectify, the process of actually finding the source of the leak is more important. If it is bandaged up as a part of the process of applying a new membrane, but it is not treated directly, nor the damage underneath fixed, then the problem is only going to get worse over time.
At Remedial we have a team of experienced professionals who are highly skilled in identifying your problems and providing you with the most ideal commercial waterproofing solution that will help you keep water-related issues at bay. If you need help with your commercial property, let’s have a chat.