Roof Leaks in Strata Buildings: What Owners Corporations Need to Know Before Storm Season

A roof leak in a strata building rarely stays one owner's problem. Water that gets in above the top floor can travel along ceiling joists, through light fittings and down wall cavities, and by the time a stain shows up in a unit the leak may have been running for months. Storm season in Sydney runs from about October to March, so now is the time for committees to get ahead of it.

This year comes with a twist. The Bureau of Meteorology declared El Niño in June 2026 and has said it could become the strongest on record, which for eastern Australia usually means a hotter, drier spring and summer with a higher bushfire risk. That is not a reason to leave the roof alone. El Niño summers still bring Sydney's afternoon thunderstorms, hail and the occasional east coast low, and a long dry spell is exactly what fills box gutters with leaf litter and dust before the first heavy downpour hits. Heat does its own damage too. Weeks of hot roof temperatures expand and crack flashings and sealants, so a roof that got through last summer may not be in the same condition when the first storm arrives.

This guide covers who is responsible for a strata roof leak, the faults that cause most of them, and how to get a leak fixed properly rather than patched again next summer.

Who is responsible for fixing the roof?

In NSW, the roof of a strata building is usually common property, which makes it the owners corporation's responsibility. Under section 106 of the Strata Schemes Management Act 2015, the owners corporation must maintain and repair common property and keep it in good and serviceable repair. If an owner suffers loss because that duty was not met, they may be able to recover it from the owners corporation.

There are exceptions. Some townhouse and villa schemes have by-laws that hand roof maintenance to individual owners, and an exclusive use by-law can shift responsibility for a particular section. Check your strata plan and by-laws, and ask your strata manager if you are unsure. The rules in other states are broadly similar, but the details differ.

Building insurance is also held by the owners corporation. Sudden storm damage is often covered, while gradual leaks and general wear usually are not, which is one more reason to keep the roof maintained and documented. The water leak responsibility guide covers how the common property line is drawn once the water is inside a lot.

The faults behind most strata roof leaks

After years of strata roof work across Sydney, the same few causes come up again and again:

• Box gutters. Many walk-up blocks and terraces drain the roof through box gutters that sit inside the building line. When they block with leaves or overflow in heavy rain, the water has nowhere to go but inside. Undersized outlets and missing or blocked overflows are common in older buildings.
• Flashings at parapets and walls. Low-pitched metal roofs behind parapet walls rely on flashings that crack, lift and pull away as the building moves.
• Penetrations added later. Solar mounts, air conditioning pipes, exhaust vents and antenna brackets added by owners or contractors over the years are a frequent source of new leaks, especially where they were sealed with silicone alone.
• Lifted or corroded roof sheets. Fasteners loosen, washers perish and sheet laps rust, particularly near the coast.
• Cracked ridge bedding and slipped tiles on tiled roofs, which let wind driven rain straight into the roof space.

Drainage below roof level matters too. A roof that drains well still floods if the downpipes and pits it feeds are blocked, which the stormwater pits and roof drainage guide covers in detail.

When a leak is reported: what the committee should do

1. Get it in writing. Ask the owner or resident to email the strata manager with photos of the stain or drip, the date it started and whether it only happens in heavy rain or wind.
2. Make it safe first. If water is near light fittings or a ceiling is sagging, the area should be kept clear and the power to that circuit switched off. A roofer can tarp or temporarily seal the roof while the permanent repair is organised.
3. Find the cause, not just the drip. Water often enters the roof well away from where it shows inside. Ask for an inspection that photographs the actual entry point, so the committee can see what it is paying to fix.
4. Compare repair against replacement. A written quote that explains whether the problem is a localised fault or the end of the roof's life helps the committee decide between a repair now and planning for replacement through the capital works fund.
5. Keep the records. Photos, reports and invoices help with insurance claims, with disputes between owners, and with the next committee.

Prevention: a simple storm season routine

• Have box gutters, valleys and outlets cleaned at least twice a year, and before each storm season. Buildings near large trees may need it more often.
• Check that box gutter overflows exist and are clear. An overflow that discharges outside is what stops a blocked gutter from flooding a ceiling.
• Ask for a roof condition report every few years, with photos, and use it to plan the capital works fund.
• Require any contractor installing solar, air conditioning or antennas on the roof to use proper flashings and to provide photos of the finished penetrations.

Strata roofs are not complicated, but they are shared, and that is why leaks tend to sit unresolved while everyone waits for someone else to act. A clear process, a maintained roof and a roofer who reports the real cause will stop most of them.

This article is general information, not legal advice. For questions about your scheme's by-laws or responsibilities, speak to your strata manager or a strata lawyer.

About the author

Joshua Liptak runs Aussie Roof Repairs, a licensed roofing business based in Oatley NSW (NSW Licence 488966C) that repairs and maintains roofs on homes and strata buildings across Sydney, including make-safe work and photo reports for committees and insurers.

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