The Importance of Waterproofing

Building or renovating your home can involve plenty of big-ticket items, but it’s the little details that can make the biggest difference. Waterproofing is a key example of this – when done properly, it should be invisible, but it’s an essential part of the building process and one that must be executed correctly to ensure ongoing structural integrity. 

What is waterproofing?

Waterproofing is the process of applying a physical barrier or membrane to prevent unwanted moisture entering your home. If left unchecked, it can lead to mould growth, rot and decay, causing unnecessary damage. The smallest amount of water can be incredibly damaging and costly to replace, so it’s important to get waterproofing right from the very start.

The Building Code of Australia (AS3740) states that all wet rooms require waterproofing, including bathrooms, laundries, balconies and roofs, as well as floors and walls adjacent to baths, large tubs, basins and sinks. It’s also used in areas like swimming pools and carparks. 

The waterproofing process

Generally, waterproofing is the one of the first processes when building a bathroom as it involves installing a barrier around the walls and floor. Like any part of the construction process, preparation is essential. 

The contractor will first clean the substrate (flooring or concrete slab) and undercut door jambs and skirting to ensure a consistent and correct application. Then, they will apply the first coat of membrane, taping corners and around penetrations. Once this is dry, they will apply a second coat. 

Once vanities have been installed and all relevant surfaces are painted, the contractor will then return to apply a final coat. This should be completed before any tiling in order to avoid damage to the membrane underneath. This process can take from 10 days to two weeks, as a correct application requires multiple layers. 

When choosing a builder, make sure you ask about the experience and training of their contractors. It’s important that their chosen waterproofer has the necessary qualifications – in most cases, this will involve a Certificate III in Waterproofing. 

Why it’s so important 

If waterproofing isn’t completed correctly, it can be catastrophic for your home. For example, if a first-floor bathroom starts to leak into lower living areas, it can cause damage to the electrical wiring, plastering on the ceiling and furniture and flooring on the lower floors. 

Unfortunately, in a circumstance like this, the bathroom would also need to be ripped up and replaced. If this occurs more than six years after the initial build, you’ll be liable for these costs, not your builder. 


At Crown Building & Construction, our team possess all the necessary skills and training to make sure your waterproofing is completed to the highest standard. Get in touch today to see how we can help with your next construction project.