Flat roofs and low-pitch roofs present challenges that most standard roofing contractors are not equipped to handle properly. Water doesn't drain off a flat roof the way it does on a pitched roof — it sits, it pools, it finds its way through any weak point in the membrane, the flashing, or the drainage design. A flat roof installed without proper knowledge of membrane systems, fall design, and drainage requirements will fail. It's not a question of if — it's a question of when.
The majority of flat roof problems we see across Sydney are the result of poor installation — the wrong membrane system for the application, inadequate falls designed into the roof, poorly lapped or unsealed joins, and flashings that were never properly terminated at the perimeter. These aren't complex problems to avoid. They're the result of contractors taking on flat roof work without the specific experience it requires.
Sterling Roof Solutions installs, repairs, and replaces flat and low-pitch roofs across Sydney using quality membrane systems appropriate for the application — torch-on modified bitumen, TPO single-ply, and liquid-applied waterproofing systems — installed to a standard that prevents the water ingress issues that flat roofs are prone to when poorly executed. Every flat roof installation is led by Gerard McCarthy, a roofer with 15 years of experience who understands what a flat roof needs to perform properly and installs it accordingly.
If you have a flat roof that is leaking, poorly maintained, or reaching the end of its life — call us for a free inspection and written quote.
Flat roof costs vary depending on the membrane system selected, the size and accessibility of the roof, the condition of the existing substrate, and the scope of the drainage and flashing work involved. The following gives a general guide — the only accurate price for your specific roof is a written quote following a site inspection.
Flat roof leak repairs: Targeted leak repairs — locating and sealing a failed flashing, patching isolated membrane damage, clearing and resealing a blocked drain — typically start from $450 to $1,500 depending on the nature of the problem and accessibility.
Flat roof waterproofing (liquid-applied over existing membrane): Application of a liquid waterproofing system over an existing flat roof in good structural condition typically ranges from $60 to $100 per square metre depending on the system specified and the complexity of the perimeter detailing. A standard garage or extension flat roof of 20–40sqm would typically cost $1,500 to $4,000 fully waterproofed.
Torch-on membrane replacement — residential flat roof: Full membrane strip and replacement using torch-on modified bitumen typically ranges from $90 to $140 per square metre including substrate preparation, new membrane, perimeter flashings, and drainage connections. A 30–50sqm residential flat roof would typically cost $3,500 to $8,000 depending on complexity and access.
TPO single-ply membrane installation: TPO installation typically ranges from $110 to $160 per square metre including membrane, welded seams, perimeter flashings, and drainage. Premium performance and longer warranty periods compared to torch-on systems.
All pricing is indicative. Contact us on 02 8875 7788 to arrange a free inspection and written quote.
Sterling Roof Solutions installs and repairs flat roofs across Sydney's North Shore and surrounding areas. We regularly work in Chatswood, Lane Cove, Willoughby, Artarmon, Mosman, Neutral Bay, Lindfield, Gordon, St Ives, Hornsby, Ryde, Meadowbank, Epping, Eastwood, Manly, Dee Why, Narrabeen, Mona Vale, and across Greater Sydney.
Flat roofing work is common across Sydney's North Shore — many homes in this area have rear extensions, garage roofs, and low-pitch roof sections that were built decades ago with flat roof systems now approaching or at the end of their life. If your flat roof is starting to cause problems, it's worth getting an honest assessment sooner rather than later — the damage a failed flat roof can do to the structure beneath is disproportionate to the cost of fixing it properly.
Not sure if we cover your area? Call us on 02 8875 7788 and we'll confirm.
This depends significantly on the membrane system installed and the quality of the installation. A properly installed torch-on modified bitumen membrane should last 15 to 25 years. A TPO single-ply system can last 25 to 30 years. Liquid-applied systems applied as a maintenance coat over an existing membrane typically extend the roof life by 10 to 15 years. The biggest factor in flat roof longevity is the quality of the original installation — particularly the perimeter flashings, drainage design, and substrate preparation.
It depends on the extent and nature of the failure. An isolated flashing failure or a localised membrane defect on a roof that is otherwise in good condition can often be repaired effectively. A membrane that is showing widespread cracking, extensive blistering, or repeated failure at multiple points is usually a candidate for full replacement. The only way to answer this question accurately for your specific roof is an inspection — and we offer these free of charge.
The most common causes are failed perimeter flashings, membrane blistering or cracking from UV degradation, ponding water from inadequate falls or blocked drains, and poorly sealed penetrations around pipes, vents, and skylights. In Sydney's climate, UV exposure is a significant factor in membrane degradation — the intense summer sun accelerates the breakdown of bitumen-based membranes, which is why regular inspection and timely maintenance matters.
Yes — flat and low-pitch roofs are a practical and popular choice for extensions, additions, garage roofs, and contemporary architectural designs across Sydney. The key is ensuring the right membrane system is specified and installed correctly from the outset. A well-designed and properly installed flat roof will perform reliably for decades. The problems arise when flat roofs are installed by contractors without the specific experience this type of roofing requires.
We recommend a professional inspection every two years as a minimum — and after any significant storm event. Flat roofs can develop problems that aren't visible from ground level and aren't causing obvious water ingress yet but will do so shortly. Early identification of membrane deterioration, blocked drains, or flashing failures allows targeted repairs that prevent far more costly damage. Our inspections are free and involve no obligation to proceed with any work.
Yes — this is something we do regularly. Poorly installed flat roofs are unfortunately common, and we're experienced at identifying exactly what went wrong and fixing it properly. In some cases that means targeted repairs to specific failures. In others — particularly where the installation was fundamentally compromised by inadequate falls, wrong membrane specification, or poor substrate preparation — a full replacement is the only way to achieve a lasting result. We'll give you an honest assessment of which applies to your situation.
From a leaking roof that appeared overnight to a full replacement that's been on your radar for years — if it's on your roof, we handle it. Tiled roofs, Colorbond, flat roofs, guttering, chimneys, skylights — Gerard has seen it all and fixed it all in 15 years on the tools. Contact your local Sydney Roofers.
