Elizabeth Bay Apartments Sydney, NSW

Proofex Torchseal tackles insulation and roof leaks in one system

While enjoying stunning views overlooking Elizabeth Bay, the residents of an older apartment block were not enjoying the heat transfer into their units caused by inadequate insulation. In fact, the building roof had no insulation at all.

The building strata managers called on BellMont Facade Engineering to solve the over-heating and manage mechanical repairs to the building services, including the heating and air-conditioning. While working on the roof, BellMont identified significant leaking. Under Sydney's intense UV exposure, the original PVC waterproofing membrane had failed.

A two-in-one solution

BellMont specified rigid foam insulation boards and three layers of Proofex Torchseal. Although primarily a waterproofing solution, layering with Proofex Torchseal is an excellent strategy to reduce energy consumption for heating and cooling. The membranes offer excellent stability at both high and low temperatures.

BellMont Remedial Engineer Rodi Bircan explains: “It is one of the best ways to provide a thermal barrier to the units below. Because the original waterproofing membrane was aged and damaged, we were able to solve both issues at once.”

Fosroc ANZ specification manager Gary Bennett says it is a common solution for older buildings. “It can be expensive to retrofit ceiling insulation when the building is occupied. This solution is easier to achieve, without any access issues. It is a relatively fast way to extend the life of a building and add value for owners,” Gary says

With Wynn Construction Group and Trusty-Seal Waterproofing on the team, the system application went smoothly.

Self-adhesive Proofex Torchseal A350 was applied directly onto the insulation to protect it from the torching process. Then the A600 base sheets and A625 top sheets were torch applied.

Designed for the Australian climate

As with this building, single layer PVC membranes can be prone to failure, especially if they are not designed for the Australia's very high UV exposure.

"Proofex Torchseal is very robust. It is designed for the Southern Hemisphere and has a long track record in Australia and New Zealand," Gary explains. “Builders really like working with Torchseal because they know it well. Designers know it works too.”

Manufactured from a bitumen and APP (atactic polypropylene) mix, the membranes are resistant to UV. The A625 top sheets also have a mineral finish for extra protection. The membranes are reinforced with a layer of non-woven polyester that delivers high puncture resistance.

Gary says layering the membranes adds further durability compared to single layer systems. "For example, if a layer is accidentally damaged during service repairs, you have extra layers of protection."

Proofex Torchseal can handle ponding and permanently wet conditions. There are obviously no curing times, so the waterproofing is instant.

A flexible solution

There are 10 membrane options in the Proofex Torchseal range, including heat protection and ventilation solutions. There are base sheets suitable for diverse substrates.

“The Torchseal range offers many opportunities for remedial works. We can do things like apply sheets over existing membranes without having to remove them. It is a cost-effective solution for minor cracking, which liquid membranes can’t really address," Gary explains.

As well as providing uniform thickness, sheet membranes can also save time on surface preparation and application costs. They can be detailed around air-conditioning vents and overflow drains on reinforced concrete hobs, as BellMont designed for the project.