Three key reasons why waterproofing roofs fails – and best roof waterproofing solutions!

Ponding dirty water on settled flat roof

As a longstanding expert in waterproofing for sectors including strata, commercial, civil, government and construction, Danrae Group implicitly understands how best to provide high-quality and permanent waterproofing solutions. We know what works – and what doesn’t.

There are a number of reasons that your waterproofing might not last as it should. Whether caused by human error or external factors, waterproofing failures can be costly to rectify… but they can often also be avoided.

Here are three key reasons why waterproofing fails, and what you need to do to ensure your waterproofing solution is sound.

Roofer cut a piece of rolled waterproofing

Poor workmanship

According to the Australian Institute of Waterproofing (AIW), poor workmanship accounts for 90% of all waterproofing failures. It’s a staggering number that perfectly illustrates the importance of choosing a waterproofing contractor with the expertise and industry know-how to deliver high-quality and compliant waterproofing diagnostic, design and remediation.

Quality waterproofing starts with adequate preparation, which will include clearing the site of debris or equipment preventing adequate access, and ensuring the surface is clean, perfectly smooth and ready for the specific membrane type as per the manufacturer’s instructions.

Laying the membrane is only one part of the waterproofing process, which may include laying a screed or insulation within the roofing membrane system, and the correct installation of ancillary parts including flashings, angles, flanges and joints. Comprehensive remediation should also include reinstallation of equipment, any rebuilding or repair work including carpentry, tiling and electrical, plus full clean-up to leave the site in pristine condition.

The AIW specifically mentions rushed work as a very common trigger of faulty workmanship. When waterproofers fail to leave sufficient time for correct curing of sealants or other materials, it will generally lead to movement, which allows for water ingress.

Residential building under construction

Wrong membrane choice

Each type of waterproofing membrane (liquid, PVC, TPO, peel and stick, and injection products), has particular properties that make it suitable for certain property types and locations such as basements, balconies or flat roofs. This might include UV resistance, flexibility to adapt to extreme heat or cold, suitability for damp environments or compatibility with certain building materials.

The wrong membrane choice for any location will adversely impact performance and longevity.

Membranes that are incorrectly installed or used for the wrong purpose may not have the desired properties that ensure waterproofing effectiveness, and are likely to fail early.

A site with residual moisture, for instance, requires comprehensive testing to assess moisture levels and a membrane that is specifically suitable to lay over damp substrate. Laying the wrong membrane may result in adhesive failure.

Flat roof covered with black olives

External factors

The most effective waterproofing solutions are tailored to client and sector, and take into account location and environment. Even with a superior waterproofing solution, external factors may affect the performance of your membrane.

It could be highly extreme storm weather, clogged drains from overhanging trees, or something as simple as birds pecking at membranes. Sometimes it may also occur after incidental damage from other contractors working in the same area.

While the first two causes of waterproofing failures should not be an issue for a qualified and experienced waterproofing team, damage from external factors is less easy to predict. It can however be addressed with a preventative maintenance plan. With regular inspection, any small issues can be detected – and treated – before they escalate.

Man using angle grinder

Why waterproofing expertise matters

Waterproofing expertise is crucial for effective waterproofing solutions. Waterproofers need to be fully qualified to work with each type of membrane, proficient in solution design for different property types and areas, and dedicated to careful and detailed work.

At Danrae Group, our team is one of the few with full capability to lay every type of membrane. With decades of experience across multiple sectors, we provide tailored and expert waterproofing solution design, remediation and preventative maintenance.

Our extensive trades experience in-house means we also take care of end-to-end project management for a seamless and superior waterproofing solution.

Please contact us for a waterproofing solution – that’s high-quality, compliant and permanent. Read more about roof waterproofing.

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