Roof leak detection Sydney: we find where the water really gets in

Roof leak detection in Sydney: why the stain is never under the leak

Water does not fall straight down through a roof. It gets in at one point, lands on the sarking or a batten, and runs downhill along the timber until it finds a gap, a nail hole or a join in the plasterboard. On a typical Sydney tile roof with a 22 degree pitch, a leak at the ridge can show up on a ceiling three or four metres away, and on a low pitched metal roof it can travel the length of a sheet. That is why a stain patched from above almost never stops, and why the first job on any leak is finding where the water actually enters.

Roof leak detection is the part of the job most roofers skip. It takes longer than a patch, it means getting into the roof space, and it is harder to charge for. We do it on every leak because a repair in the wrong place is a repair you pay for twice.

The six places Sydney roofs leak

After enough leak visits the pattern is clear. In rough order of how often we find them:

1. 1Ridge and hip capping. The cement bedding under the caps cracks and washes out after 20 to 30 years. Water runs under the caps and down the battens. The stain appears well below the ridge, which is why this one gets misdiagnosed as a broken tile.
2. 2Valleys. The metal valley iron rusts through, or leaf litter dams the valley and pushes water sideways under the tiles. Common in leafy suburbs and anywhere within a few kilometres of the coast.
3. 3Flashings. Chimneys, skylights, aircon and solar penetrations, and the join where a lower roof meets a wall. Flashings that were sealed instead of turned in fail as soon as the sealant does.
4. 4Cracked, slipped or porous tiles. Real, but less common than people think. A single cracked tile usually only leaks if the sarking under it has also failed.
5. 5Sarking that has gone. Older Sydney roofs often have no sarking, or foil that has perished to dust. With no second barrier, wind driven rain that gets past the tiles goes straight into the ceiling. These roofs leak in storms and are dry the rest of the year.
6. 6Metal roof screws and laps. On Colorbond and zincalume, the neoprene washers perish, screws back out and the sheet laps open up. The leak is a row of drips, not one spot.

How we find a roof leak

There is no gadget that replaces a roofer in the roof space during rain, but there is a method, and it is the same one every time.

1. 1Inside first. We look at the stain, then go into the roof space above it with a torch and follow the water marks on the timber uphill. Tide marks on battens and rafters point to the entry like an arrow. On a dry day a moisture meter tells us which timbers are still wet and which dried out years ago.
2. 2Then the roof. We walk the roof above the water trail and check each of the six points above, in order. Most leaks are found at this stage.
3. 3Water test when it is not obvious. With one roofer in the roof space and one on the roof with a hose, we wet the roof in sections from the bottom up until water appears inside. Working uphill matters: start at the ridge and everything below it gets wet at once, and you learn nothing.
4. 4Photograph the cause. You get a photo of the actual entry point, not a description over the phone, and a fixed written quote for the repair.

Thermal imaging, drones and leak detection gadgets

Thermal cameras show temperature difference, and wet insulation is cooler than dry, so an infrared scan of a ceiling from inside can show the shape of the wet area quickly. That is useful on a large flat ceiling or a commercial roof where crawling the whole roof space is not practical. It does not show where the water got in, only where it ended up, so it is the start of the trace, not the end of it. Drones are good for a look at a steep or fragile roof before anyone walks on it. Neither replaces the water test, and a detection service that offers a camera report without getting into the roof space is selling you a picture of your stain.

What roof leak detection and the repair cost

Finding the leak is part of the free inspection. What you pay for is the repair, and there are two kinds. By the time a leak shows on a ceiling it has usually damaged more than the entry point: wet sarking, softened battens, bedding gone along a ridge line.

Leaks that only show in heavy rain

A roof that is dry for months and then leaks in a storm is usually telling you one of two things: there is no sarking (or it has failed) so wind driven rain that gets past the tiles has nothing to catch it, or a gutter or valley is overflowing back under the roof line. Both are found the same way, but the fix is different. The first is a sarking retrofit under the affected section, the second is a gutter or valley job. Patching tiles fixes neither.

What to do before we arrive

Photograph the stain and note when it appears (steady rain, heavy rain only, wind from a particular direction). Move anything electrical out from under it. If the ceiling is sagging keep clear of it. Do not get on the roof and do not let anyone put silicone on it before we have traced the leak, because sealant over the wrong spot hides the evidence. If water is coming through right now, the emergency roof repairs page covers make safe and priority scheduling.

Roof leak detection across Sydney

We trace leaks across the Sutherland Shire, St George, Northern Beaches, North Shore, Inner West, Eastern Suburbs, Hills District, Western Sydney and South West Sydney. Coastal suburbs get rusted valleys and screws; leafy suburbs get blocked valleys; the Hills and the west get sarking that has perished in the heat. Same method everywhere.

Roof leak detection Sydney: FAQs

Once the leak is found: roof leak repairs Sydney covers the repair itself, the warranty and what it costs. For leaks in the wake of a storm, see storm damage repairs and the insurer ready photo report.