Roof And Gutter Leaks That Are Not Plumbing

A wet patch on a top floor ceiling gets logged as a plumbing job. A plumber attends, tests the fixtures, finds nothing, and leaves.

Nothing was wrong with the plumbing. The water came from outside, and it only arrives when it rains, which is why the test found nothing on a dry Tuesday.

The tell

Ask one question. Does it happen after someone showers, or after it rains?

Rain-driven means roof, gutter, facade or balcony. Use-driven means plumbing or waterproofing. That one answer saves a wasted visit more often than any other question we ask.

Sometimes the answer is both, because a slow leak has been damaging a ceiling for months and a storm made it obvious.

Box gutters

On a lot of Sydney apartment buildings the roof drains into an internal box gutter rather than to an eave.

A box gutter is fine until it cannot keep up. Then it fills, backs up past the upstand, and discharges directly into the building. Not a drip. A volume.

The causes are always the same. Leaves and debris in the gutter. A blocked or undersized outlet. A downpipe that has partly collapsed. An overflow that was never installed or has been sealed over during a re-roof.

A box gutter needs a working overflow, because that is the thing that decides whether a blockage becomes a nuisance or a flood.

Ordinary gutters

Rust at the back edge is the one to look for. Water sits there, and once it goes through, the leak is behind the fascia rather than over the front, so it goes into the building rather than onto the ground.

Falls matter too. A gutter that has sagged holds water permanently and will rust out at the low point.

Flashings

At every junction between the roof and a wall, a parapet, a chimney or a penetration, a flashing is doing the work. They fail quietly.

The classic is a step flashing that has lifted where render was applied over it, or a penetration flashing that has hardened and cracked. Neither is visible from the ground and both leak only in wind-driven rain, which makes them intermittent and easy to dismiss.

Balconies above

Water on a top floor is not always from the roof. A balcony one level up with a failed membrane or a blocked outlet will do the same thing on the same schedule.

Worth checking before anyone goes on the roof, because it is a lot easier to inspect.

Why this belongs with the trades below it

The leak is a roofing and carpentry problem. The damage is a plastering and painting problem. And in a lot of cases the ceiling has to come down to find the entry point in the first place.

Booked as three trades, the ceiling stays open while everyone waits for the next one. Booked as one job, the diagnosis, the repair and the reinstatement run together and the resident gets their ceiling back in the same week.

What to do at the report

Note the weather. Photograph the extent with a date. Check the gutters and outlets above the affected unit before booking anything, because a blocked outlet is visible and free to confirm.

We take roof, gutter and flashing work with the building and painting reinstatement attached, so a rain leak is one job rather than a queue. If you have a ceiling that only goes wet in a storm, send it through with the dates.