UQ Herston Campus Herston, Queensland

The Health Sciences building at Herston experienced significant water damage when the existing bitumen waterproofing membrane covering the expansive roof failed.

Triple-layer, torch applied waterproofing solution 

Following a site inspection, Fosroc ANZ Specification Manager Shawn Perry recommended removing the existing failed membrane and installing a new torch applied sheet membrane system. 

"The existing bitumen sheet membrane had been in place for about ten years, and had deteriorated to the point of failure," he explains.

"There had been issues with pooling, and water ingress had caused significant damage to ceilings within the building. We needed a solution that provided excellent waterproofing properties, was compatible with the existing substrate and UV stable."

The recommended system comprised:

• Primer 24
• Proofex Torchseal A600
• Proofex Torchseal A825
• Nitoseal MB175
• Proofex Torchseal Pressure Seal Flashing

Shawn explains that under this system, Proofex Torchseal A600 can be applied in one or two layers.

"Clients often choose to apply two layers to enhance durability and extend the warranty terms," he explains. "This has the added benefit of adding an additional layer of insulation to the building which can help reduce energy consumption for heating and cooling."

Expert application

Fosroc ANZ Account Manager, Eric Repetto, explains that the torch application of Proofex Torchseal sheet membranes should only be undertaken by trained experts.

"It's a job that demands great skill, patience and expert preparation," he says. "You don't want to be cutting any corners with a job like this."

"The applicators in this instance, Concrete Seal, did a fantastic job," he says. Concrete Seal followed a strict process for the installation of the new waterproofing membrane.

Step 1: The existing waterproofing membrane was removed from approximately 1000sqm of rooftop and the substrate ground back to bare concrete. Air conditioning units situated on plinths on the roof were removed to enable the entire surface to be prepared and the membrane applied.

Step 2: The roofing surface was primed with Primer 24 at a rate 0.13 litres per m2. The primer was left to dry for at least 30 minutes, until it was touch dry.

Step 3: The first layer of Proofex Torchseal A600 was applied using a gas torch, maintaining at least a 100mm overlap between adjoining sections. Special attention was paid to ensure joints occurred in suitable locations. Nitoseal MB175 was used to seal terminations of the membrane.

Step 4: A second layer of Proofex Torchseal A600 was applied to provide increased, longer lasting protection. 

Step 5: A top layer of Proofex Torchseal A825 was applied using a gas torch, again maintaining sufficient overlap between adjoining sections.

Step 6: On completion of the membrane installation, all exposed perimeter edges were terminated under pressure seal flashing and sealed with Nitoseal MB175.

The entire process took a team of trained expert installers approximately one month to complete

Durable, long-lasting protection with insulation benefits

The double layer of Proofex Torchseal A600 provided a long-lasting waterproofing solution, with guaranteed performance of more than 15 years. 

The Proofex Torchseal A825, with an upper side encrusted with a layer of grey slate granules, provided additional UV resistance ideal for this exposed rooftop.

The triple layer system not only ensured a watertight roof, but provided additional insulation for the building, reducing the energy consumption for heating and cooling.

Find out more

Download one of our Torchseal brochures (links are included below), or scroll down to complete our enquiry form. Our expert team will be in touch to discuss your needs and provide a tailored specification.