An image of the Victorian State Library's roof in Melbourne during waterproofing work carried out by Flex A Seal

Victorian State Library, May 2015

The upper structures of the State Library are currently being restored and there’s no surprises as to why the work is necessary – water ingress in various forms! A vital component of the overall work is to guarantee leakage mitigation, making Flex A Seal’s participation particularly significant.

The large, octagon-shaped, dome roof was replaced 20 years ago, with the surrounding gutters replaced with Rheinzink (titanium zinc) at the same time. This installation has been mostly successful. The exception is the gutter construction: insufficient allowance for thermal movement led to ruptures of the gutter structure joints, resulting in leaks that have affected interiors beneath the dome.

This problem was compounded by the dwarf parapet wall built in front of the gutter, designed to prevent flood water from overflowing onto the roofs below during torrential storms. Despite in-built overflows within the parapet (of which there were too few), water would fill the gutters and flood the underside of the roof space during storms, with the parapet acting as containment.

In charge of the project are specialist heritage architects Lovell-Chen, who elected to line the gutters with a PVC sheet membrane system. Wolfin waterproofing membrane system was chosen through a selection process with Flex A Seal Pty Ltd contracted for installation.

The advantage of installing Wolfin PVC membrane system was that it could be done as a retrofit directly onto the Rheinzink gutters without disruptive co-procedures involving removal of any part of the main dome roof. The membrane is also flexible and sturdy enough to cope easily with the prevailing structural and atmospheric conditions.

Flex A Seal’s precondition for winning the tender was that a flexible and effective installation design method to be worked out. The builder (HBS Group) and architect had previously agreed to remove the dwarf parapet as an obvious design improvement (see photos #2 and #3). However, even after the removal of the parapet, there was limited space and careful stage-by-stage planning was needed. The job required a combination of preassembled and in situ installed membrane and flashing components, as well as progressive quality control checks.

Our collaboration with the builder’s site manager made it possible for our staff to work in optimal conditions, making our role both interesting and worthwhile.

Candlebark School Library waterproofing project - the completed job.

Candlebark School Library, 2011

Candlebark School is not your ordinary school. Founded by children’s author John Marsden, it sprawls over 1100 acres, most of it bush, an hour north of Melbourne. When a new library was needed, the decision was made to put it underground, thereby preserving the view of the valley below, increasing thermal efficiency and providing a last-resort shelter from bushfire.

The library is an earth-covered timber structure sitting on a concrete slab, buried 0.5 metres below the ground at one end and meeting the natural ground level at the other. The exposed rim of the library’s roof is concrete, which connects and interlocks with retaining walls made from reinforced blockwork at the back. The roof’s core is lightweight, sheeted with plywood, yet capable of supporting its heavy load.

The success of the project relied upon the vision of Paul Haar Architects, the ingenuity of Keith Long & Associates engineers and the waterproofing expertise of Flex A Seal. Keith Long & Associates made significant contributions to the design of the structure, while Flex A Seal’s collaboration ensured an effective method was used to make the structure watertight and enable successful subsoil drainage. Flex A Seal also provided the membrane used to waterproof the earth-covered roof (a Flex A Seal PVC sheet membrane system).

The library was completed in 2011, winning six Australian Timber Design Awards the following year.

More than four years after its completion, the Candlebark library is an unqualified success – not only a beautiful, comfortable, versatile space, but also – more importantly – robust, intact and dry. This was an especially significant project for us as the environmentally sensitive, clever design and innovative construction techniques reflect Flex A Seal’s own values and sense of purpose.

Waterproofing work conducted by Flex A Seal in Melbourne at the Newmarket Power Station

Newmarket Power Station, 2013

This majestic, 100-year-old building tucked away in a side street of Flemington was one of three power stations built to electrify the early suburban railway network. Whilst the other two power stations became developer projects, the Newmarket Power Station will continue to serve the rail networks as a substation and remains a functional historic building. All the more reason that we were determined to give our utmost to restore its roof.

Built in 1914 during the Federation period, this building experienced a timely turnabout when Metro Trains management contracted us to refurbish the roof as part of an overall restoration project.

Adam Monaghan from Southern Cross Environmental Services, whose men undertook the removal of asbestos fibre surface coating, reported counting approximately 50 roof leaks throughout the building before works began.

As is typical in these types of projects, Flex A Seal opted to install its signature PVC membrane. Its inherent robustness along with the quality installation regime exercised by our tradesmen ensured 100% success with zero leaks evident at project completion.

Whilst all of the inner parapet-wall surface areas received a cosmetic liquid membrane application, the wall-capping received a new coping surface that makes the 140 x 60 metre wall sections far less prone to moisture-induced cyclic movement and subsequent crack formation.

A commercial agreement with Metro Trains ensures that Flex A Seal personnel will inspect this power station roof periodically as part of its quality control maintenance. In this way we ensure that our client can remain confident in a leak-free Newmarket railway substation and maintain this building of scientific and architecturally importance to the state of Victoria.

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