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Why is Waterproofing so Important in Construction?

Waterproofing is the process of creating a means to prevent liquid from entering a structure. Creating a waterproof barrier against moisture is an essential part of the construction process and the upkeep of the building. Moisture penetration can lead to a variety of problems, from unsightly water marks and mould to severe structural damage.

Different projects and areas require different approaches when it comes to waterproofing, hence why there are a variety of products available. On this page, we’re having a closer look at why waterproofing is important and the protection options on the market.

Why Do You Need Waterproofing?

You may think a little water never hurt anybody, but moisture can be very damaging to your building’s structural integrity. Whether you’re building with concrete, timber, cement, or masonry, water can lead to a range of issues including rot, mould, mildew, cracking, water damage, or even structural and foundation issues. All these issues will get worse over time and can cost a lot to fix. For longevity and lower maintenance requirements, prevention is the best cure for water damage.

Waterproofing prevents seepage and moisture infiltration, giving a building better structural integrity and protection against the elements. By stopping water before it can enter your building, you’ll greatly reduce maintenance needs and costs and increase the lifespan of the structure.

waterproofing around house

Benefits of Waterproofing in Construction

  • Improves building durability and lifespan

Moisture penetration and dampness can lead to structural and foundation issues and serious issues like rot and cracking. This makes water damage one of the leading causes of decreased durability in commercial buildings. Buildings with waterproofing have a noticeably longer average lifespan than those without it.

  • Prevent leakage

Waterproofing is the best means of reducing your chances of leakage, even during extreme weather or in the dampest areas of the house.

  • Improve health and safety conditions

Damp environments are perfect for mould, bacteria, and fungi. These are not only eyesores that gradually destroy your building, but they can also lead to serious health issues.

  • Improve air quality

Excess moisture lowers the overall air quality and can make life especially difficult for those with health issues such as asthma, lung issues, or immune system issues. 

  • Better energy efficiency

The added barrier provided by waterproofing helps improve your building’s energy efficiency, meaning less reliance on heating and air-conditioning.

  • Cost-effectiveness over time

Repairs are often expensive, with mould removal and structural repairs often costing thousands, if not tens of thousands, of dollars. Waterproofing is a long-term investment that will reduce maintenance and repair costs for decades to come. 

  • Increase property value

Waterproof structures require less maintenance and are seen as sturdier, making them easier to promote as a safer investment when put on the market. 

Tackling DIY Waterproofing  

A question some of our handier readers no doubt have is, can you install your own waterproofing? 

In New South Wales the answer is yes, provided the overall cost of the project is under $5,000. If the job exceeds this cost, it legally needs to be done by a licenced professional. While you won’t need a water certificate for this work, you will need to have your work inspected and approved by a certified body to ensure your work is safe and meets all legal requirements.

waterproofing the deck

One of the key parts of a successful waterproofing job is choosing the right product for your needs. There are a lot of different products on the market, so if you’re feeling unsure, talk to one of our friendly, expert team about the best choice for you. 

If you’re waterproofing different parts of your home, you may find that more than one product is required (for example, waterproofing a swimming pool is different from doing the same to your bathroom).

Each waterproofing product is a little different, so even if you’ve done this before, it’s important to pay attention to the information provided. Deviating from the instructions even a little can affect the overall effectiveness. 

Types of Waterproofing Materials

When it comes to waterproofing products, you have a wide range of options. Below, we’re having a quick look at each product, how they work, and what they’re most used for. 


Admixtures are components added to concrete to help improve its integrity. It achieves this by filling the micro spaces that allow water and other contaminants to enter your material and lead to eventual breakdown. Admixtures are usually crystalline or pour-blocking and are either added at the plant or directly to the surface after pouring the concrete.

Cementitious waterproofing coatings

Cementitious waterproof coatings are usually applied as a slurry coating to masonry surfaces. These products are available in single-part (requires the addition of water) and in double-part (requires a special liquid additive rather than water). An advantage of this product is it can be rendered after being applied. Cementitious coatings are ideal for a basement, retaining walls, water tanks, and similar structures.

Liquid waterproofing

Liquid waterproofing products can be applied by hand or spray. They are easy to apply, have a long or no pot life limit, and are more affordable than other waterproofing options, making them the most popular product on the market. Liquid waterproofing can be applied to flat or sloped external surfaces and is ideal for decks and podiums.

Sheet waterproofing

As the name suggests, sheet waterproofing is a continuous layer that is added over a surface to prevent water penetration. Depending on the product you purchase, sheet waterproofing is available in a range of thicknesses and comes either loose or on a roll. 

A distinct advantage of sheet waterproofing is it is much easier to create an even membrane, eliminating the risk of thinner spots. It’s more expensive than other options and requires special equipment and skills to install properly. Therefore, it should only be installed by approved applicators.


Waterstops are a waterproofing option designed for cast-in concrete projects to create watertight seals around movement and construction joints. There are two types of waterstops.

Swellable waterstops create a pressure seal by swelling in the presence of water.

PVC waterstops maintain a specific shape but make it difficult for water to enter through gaps and joints.

Both types are effective, though swellable tends to be easier to apply.

Get Ready for Your Weatherproofing Project

Waterproofing is an essential element in building construction, and therefore, you want the best quality products to ensure the durability of your building. Choosing the right waterproofing product and installing it correctly will significantly improve your house’s protection against water damage. 

At Illawarra Industrial Supplies, we have a wide range of quality waterproofing products and the expertise to guide you in making the right choice for your project. To learn more or to purchase waterproofing products, get in touch with us today!

  • Australasian Corrosion Association
  • Association for Materials Protection and Performance
  • Illawarra Innovative Industry Network
  • NACE International
  • The Society of Protective Coatings