Three common strata waterproofing problem areas – a five-step solution

Residential apartments at sunset

With long-standing experience in commercial and residential strata waterproofing, Danrae Group has seen every sort of waterproofing issue.

While poor quality waterproofing is a major contributor to strata defects, there are several common problem areas that if neglected will likely lead to water ingress, affecting your tenants and your property.

Residential and commercial strata property managers are responsible for maintaining the strata building and ensuring the safety of tenants, so it’s very important to have a comprehensive waterproofing solution.

Here are five common problem areas in commercial and residential strata – and Danrae Group’s five-step strata waterproofing solution.

Flat roof with air conditioners on top modern apartment house building

Flat roofs

Flat roofs can’t rely on the natural slant of a sloped roof to remove water, so it’s imperative to have a comprehensive solution design that includes adequate drainage. Without it, water is likely to pool on your roof after heavy rain or storms.

Ongoing pooling can damage your waterproofing membrane, and with nowhere to go but down, water will seep into the ceiling cavity through tiny cracks, and eventually into the apartments or offices below.

Other potential problems impacting roof waterproofing include poor quality membrane installation, clogged drains, crocodiling or blistering on the surface or flashing failures due to incorrect priming or installation. Extreme climate conditions may also hasten general wear and tear on your waterproofing membrane.

If undetected and untreated, water ingress from your rooftop will likely cause issues in the apartments or offices beneath, including mould, efflorescence and concrete spalling.

Sea view from a large terrace with a glass partition


Balconies are exposed to the climate, and without quality waterproofing can be a prime channel for leaks. Your waterproofing solution should allow for adequate flow away from the building façade, with suitably sized drains and the correct number of drain outlets.

It’s also very important to choose the right waterproofing membrane for the environment, suitable substrate layers and coatings plus careful remediation to ensure tiles or other layers above the membrane are watertight.

Water that seeps into walls from balconies may not be immediately visible, but can eventually manifest as mould, flaking paint, cracks or crumbling plaster. If left untreated, this can result in efflorescence, concrete spalling and concrete cancer.


Given their subterranean location, basements are frequently damp and vulnerable to water seepage from the surrounding earth. This can worsen with increased pressure or a rising water table after heavy rain. Broken or damaged piping or water ingress from ineffective waterproofing elsewhere in the building can also cause problems in basements.

Typically, signs that you have a waterproofing issue might include mould, rust stains on metal surfaces, flaking paint, crumbling plaster, rotting wood or stained and discoloured floors.

Efflorescence is also very common – a mineral deposit build-up (it looks like a white powdery coating) that can affect brick, concrete and clay tiles.

Vertical cracks in basement walls often appear with age; however, they may also be a sign of moisture. Horizontal cracks usually appear when there is pressure on the other side – so you need to get them checked urgently.

Our five-step strata waterproofing solution

Danrae Group uniform

At Danrae Group, we’ve implemented proven processes to ensure our strata, commercial, civil and government clients get the waterproofing solutions they need. Our end-to-end waterproofing management includes:

  • Expert diagnostic – using team knowledge and the latest technology
  • Solution design – tailored to premises, location and environment
  • Waterproofing installation & remediation – expert and detail-orientated
  • Testing and handover – we triple test every solution and provide a full waterproofing guarantee
  • Preventative maintenance – with three levels of preventative maintenance plans, we keep your waterproofing in top shape and catch any issues at the earliest stage.

Danrae Group is one of the few waterproofing companies with an in-house team of expert waterproofers trained in every brand and technique, plus trades specialists including carpenters, builders and tilers.

It means we can oversee end-to-end project management and provide our proven five-step strata waterproofing solution.

Danrae Group are the waterproofing experts. For strata waterproofing that best protects your tenants and property, please contact us.

Waterproofing News & Articles

Waterproofing 101 for strata managers – the scope

Strata managers often need to oversee all aspects of administration and facilities management which may mean getting to know diverse aspects of building construction and maintenance… including waterproofing. For the waterproofing process to run smoothly and efficiently, it’s important that you understand the importance of a clear and comprehensive scope – and why following scope recommendations will make all the difference.

Read More

Concrete cancer and concrete spalling: what you need to know

Danrae Group have decades of waterproofing expertise in-house. So not only can we look after every stage of project management and lay every type of membrane, we understand every potential problem. And that means we’re experts in diagnosing and treating two of the most common issues: concrete spalling and concrete cancer.

Read More

Failing building? Superior waterproofing solutions

Apartment blocks have been in the news over the last couple of years – and not in a good way. Major faults have led to major fails. But with the right expertise in waterproofing diagnostic, design and remediation, strata owners and managers can expect exceptional and long-lasting waterproofing solutions.

Read More


for more information