Remove and reinstate bituminous torch-on membrane

WS Remedial Group NSW was engaged to inspect a leaking concrete rooftop of a commercial building in Sydney and to provide an asset-preserving remedial waterproofing solution. During the inspection, our NSW inspector found several areas where the existing torch-on roof membrane had failed.

Our recommendation was to remove the existing membrane, carry out surface preparation, apply a moisture-barrier primer system, and install a heavy-duty, two-layer, modified bituminous torch-on membrane on the roof to form a fully bonded, continuous barrier to water penetration. The mineral chip finish on the top layer provides excellent UV protection. WS Remedial Group NSW leak sealing specialist team also removed sections of brickwork to terminate the membrane as per the manufacturer’s specification. The membrane system was detailed to all penetrations and junctions. Once the membrane was applied, a flashing was installed over the entire parapet.

The system will be supported by the manufacturer’s warranty for 20 years.

THE PRIME CAUSES OF BREACHES IN THE WATERPROOF MEMBRANE:

• Insufficient substrate preparation.
• Incorrect product specification – A waterproof system that does not fit for the purpose and/or the environment the rooftop is exposed to.
• Failure to prime the respective parts and surfaces before the application of the membrane.
• Seam failure and other installation errors, such as adhesion failure between the primer and the membrane.
• It is possible for water to get trapped between the two layers of roofing during application or repair. Therefore, torch-on roofing systems must be installed in dry conditions.

 

Minimising water damage from water ingress is key to protecting the building’s lifespan and preserving its value. Regularly inspecting rooftops is critical because if you discover early-onset defects in the waterproof membrane or other entry points for water, you can remedy them before they become a bigger problem. A seemingly small issue may grow into a big problem if left untreated or incorrectly repaired.

Cracks and voids can form in concrete due to thermal expansion, contraction, concrete shrinkage and building movement, so water will likely seep through these voids if there are any breaches in the waterproof membrane.

Roofs are constantly exposed to direct sunlight and rain, making them vulnerable to tremendous environmental stresses that can affect their physical properties and performance. Selecting the correct waterproofing system is imperative to keeping the roof water-tight, ensuring structural integrity, and protecting the residents’ homes and assets.

Proper design of falls is essential to the overall drainage of a flat roof. Falls create flow paths to direct the rainwater away from the roof to suitable discharge points. To be effective, it is essential to clear surface water from the flat roof as rapidly as possible to avoid ponding or stagnation.

“The key to successful remedial waterproofing is thorough surface preparation and vigilant detailing of all penetrations and junctions, married up with high-quality materials.”

If you have any issues with water ingress, rooftop leaks, leaking balconies, cracking concrete slabs, structural cracks, concrete deterioration, deteriorated joints, moisture, seepage, efflorescence, rising damp and/or high-flow active leaks in concrete structures, we would be happy to assist you. You are welcome to contact us with any questions that you may have.