How to Fix a Leaking Roof (And When You Shouldn’t Try)

Leaking right now?

Do not get on the roof in the wet. Catch the water, move what matters, and call. Active leaks get priority scheduling seven days a week.

Call 1300 304 162

First, deal with the water inside

Before anyone thinks about the roof itself, the job is to stop the damage spreading through the ceiling. Put a bucket under the drip. Move furniture and anything electrical out of the way. If the ceiling is bulging or sagging, that is a pocket of water sitting in the plaster and it will come down eventually, so keep people out from under it.

One thing worth doing while you wait: photograph the stain from inside, and note the time and what the weather was doing. A leak that only shows up in driving rain from one direction tells a roofer something very different to a leak that runs every time it rains at all. That single detail often saves an hour of hunting.

Why the leak is almost never where the stain is

Water does not fall straight down once it is inside a roof. It gets in at the entry point, runs along a batten, a rafter or the underside of a tile until it hits something that stops it, and only then drops onto the ceiling. It is completely normal for the entry point to be metres away from the wet patch, and often further up the slope.

That is why patching from inside the ceiling never works, and why sealant squeezed over the nearest suspicious looking crack usually just moves the problem somewhere less convenient.

How a roof leak actually gets found

Proper leak detection is done from inside the roof space first, not from the top. In daylight you can often see pinholes of light where they should not be. Water staining on the timbers shows the path the water has been taking, and following that path uphill leads back toward where it got in. Only once there is a candidate does anyone need to go up top and confirm it.

Common entry points on a Sydney tiled roof, roughly in order of how often they turn up:

Cracked or slipped tiles, and tiles that have been walked on by someone installing something else
Failed pointing and bedding along ridge capping
Valleys that have rusted through or filled with debris
Flashing around chimneys, skylights, vents and wall junctions
Gutters and box gutters overflowing back under the tile line
Sections of roof sitting below the minimum pitch for the tile profile, where wind driven rain tracks back up under the laps

That last one is the difficult one, because nothing looks wrong. Every tile can be intact and correctly laid and the roof will still leak, because the tiles alone were never going to keep water out at that angle.

Roofer pointing to cracked bedding mortar under lifted ridge capping on a Lugarno tiled roof — Finding the cause. Under the capping the bedding had cracked and gone to sand, which is a direct path into the roof. This is what leak detection actually looks like: not guessing from the ceiling stain, but getting to the point where someone can put a finger on it.

What we found on this roof

Before getting to the repair, the thing worth showing is what was already there. Someone had been at this roof before.

Strips of foil tape and smeared sealant stuck over old terracotta roof tiles as a previous leak repair — A previous attempt at the same leak. Foil tape stuck across the tiles and sealant smeared over the joins.

That is foil tape and sealant applied straight over the top of the tiles. It is the single most common thing we find when we get called to a leak that has been going on for a while, and it is almost always someone trying to stop water at the point where they can see it rather than at the point where it is getting in.

It does not work, for a reason that is easy to miss. Patching over the top blocks the path water was taking and pushes it sideways into the next gap along. The leak appears to stop for a while, then comes back somewhere else, usually worse.

Why it was never going to work

When the tiles came off, this is what was underneath.

Roof tiles removed showing battens and rafters with no sarking, open straight through to the roof cavity — Tiles lifted, and there is nothing between them and the inside of the house. No sarking, no underlay, just battens and open cavity.

There is no sarking under those tiles. There never was. You are looking straight past the battens into the roof space, and that is not damage, that is how the roof was built.

This surprises a lot of homeowners, so it is worth being plain about it. A great many Sydney tiled roofs have no secondary barrier at all. The tiles are the entire waterproofing system. They shed water down the slope and rely on gravity and overlap to do it, which works well when the pitch is right and the tiles are sound.

Take either of those away and there is no backup. On an under pitch section the water is not running off fast enough, it pushes back up under the laps, and with nothing beneath it, it drops straight onto the battens and through to the ceiling. Which is exactly what had been happening here for years.

Now the tape makes sense. Someone was trying to seal the top surface of a roof that was never sealed in the first place, on a section where the tiles were physically incapable of doing the job on their own. No amount of tape was going to fix that, because the problem was not a hole. The problem was that the roof needed a second line of defence it had never had.

What it had cost

Because the water kept getting in for years while it looked like it had been dealt with, it had been sitting on the timber the whole time.

Roof battens rotted through and delaminating from long term water damage — The battens under the affected section. The timber has gone soft and stringy, which is years of water, not one storm.

Rotted timber batten at the eave line above the gutter, degraded through from water damage — The same story down at the eave. Battens are what the tiles hang on, so once they go the tiles above them are no longer properly supported.

This is the actual cost of patching a leak instead of fixing it. The tape was cheap. The rotted battens underneath it were not, and every year the leak stayed live added to that bill.

What a real leak repair looks like

Here is the job from 31 July 2026, a tiled home in Lugarno in southern Sydney, walked through as it happened. It is the common case: a roof that leaks, an owner who does not want to spend replacement money, and a targeted repair that solves it.

The decision

The thorough fix for a roof in this condition is to strip the whole thing, sark it end to end and re-lay every tile. That works, and on a roof at the end of its life it is the right call. On this roof it was not, because the rest of the roof was doing its job. The failure was concentrated in an under pitch section, meaning a run of roof sitting at a shallower angle than the tile profile is rated for, so in heavy or wind driven rain the water pushes back up under the tile laps instead of running off.

So the work was confined to the section that was actually failing.

The repair

Tiles lifted off the under pitch section along with the old battens
That section stripped back to the original structure, and the rotted timber dealt with
Extra heavy duty roof sarking installed, the secondary barrier the roof never had, so anything that gets past the tile line is caught and drained away instead of dropping into the roof space
Tiles re-laid over the new work
Every leak identified in the roof space addressed individually while the roof was open

Roof section stripped with tiles lifted and stacked in rows across the remaining roof — Tiles come off and get stacked on the roof rather than carted down, because most of them go straight back on. Only the broken ones get replaced.

What it looks like while it is happening

Worth setting expectations, because this is the part people ask about. For a day the roof is open, your tiles are stacked in rows across the rest of the roof, and there is a skip or a stack of old timber somewhere in the yard. It is noisy, there is dust, and it looks considerably worse halfway through than it did before anyone arrived.

The section that is open gets closed the same day. Nobody leaves a roof open overnight, and if weather turns before the tiles are back on, it gets covered.

New timber battens fixed over Monier roof sarking across a stripped roof section — The actual fix. Monier sarking laid across the stripped section, new battens fixed over the top of it, ready for the tiles to go back on. Everything you can see here disappears under the tiles and none of it existed before.

That green sheet is the whole job. It is the layer this roof never had, and it is why the same rain that has been coming through for years now runs down it and out into the gutter instead.

Heavy duty roof sarking laid over the eave and finishing above the new gutter — The detail that matters. The sarking is carried right down over the eave and finished above the gutter, so anything getting past the tiles drains into the gutter instead of running back behind the fascia. This is the part of the job nobody ever sees.

The gutters, while we were there

The old gutters and fascia covers came off and a new high front quad gutter system went on, along with new fascia covers and barge flashings. Worth doing in the same visit for a straightforward reason: the access, the setup and the travel are already paid for. Coming back in a year to do the gutters separately costs the homeowner more than doing it now.

Old gutter stripped off leaving bare weathered fascia timber and exposed rafter ends — Old gutter and fascia covers off. This is the part of a house nobody ever looks at, and it is usually in worse condition than the roof above it.

New quad gutter and fascia covers installed along the full length of the eave — The same eave with the new high front quad gutter, fascia covers and barge flashings on.

New quad gutter and fascia covers meeting at an external corner — The corner return. Mitred rather than butted, which is the bit that leaks if it is done lazily.

Completed tiled roof with tiles relaid and a new quad gutter running the length of the eave — Back together in Lugarno. The repaired section is in there and you cannot pick it, which is the point.

The roof still looks its age in the finished photos, because it is its age. Nobody paid to make it pretty. They paid to stop water coming into their house and to stop it eating the timber, and that is what they got, for a fraction of what a full replacement would have cost.

What roof leak repairs cost in Sydney

For a targeted leak repair of the kind above, meaning a defined section stripped back, sarked and re-laid rather than the whole roof, the range in Sydney is roughly $4,000 to $6,000. That is the honest working range, not a quote, and where a job lands inside it depends on the things below.

Set that against the alternative. A full tile roof replacement on a typical Sydney house runs into the tens of thousands, and our own roof replacement cost calculator will price yours from satellite in about thirty seconds if you want the comparison in front of you. The reason this job was worth doing as a repair is that it solved the problem for a fraction of that number, on a roof where most of the tiles were still doing their job.

The trap to avoid is the other direction. Two hundred dollars of tape and sealant looks like the cheap option right up until you are paying to replace battens that rotted underneath it, which is precisely what happened on this roof before we got there.

What does move the number, whatever the range turns out to be: how much roof has to come off, whether the battens underneath are sound, access and pitch, and whether the cause is one entry point or several. A single cracked tile and a failed under pitch section are the same symptom and very different jobs.

If what you are actually weighing up is repair against replacement, our roof replacement cost calculator measures your roof from satellite and prices a full replacement, so you can see what the expensive end of the decision looks like before you commit to anything.

Does home insurance cover a roof leak?

The general rule in Australia is that insurers cover sudden and accidental damage, and exclude gradual deterioration and lack of maintenance. A tile cracked by a falling branch in last night's storm is usually a claim. A valley that has been rusting for fifteen years usually is not, because from the insurer's position that is wear the owner was expected to keep on top of.

Where it gets argued is the middle: storm damage on a roof that was already tired. Insurers will often accept the storm damage and decline the underlying condition, which can leave you covered for part of a repair.

What helps a claim, regardless: dated photos of the damage, the weather on the day, and a written report from a licensed roofer describing the cause rather than just the fix. We provide that report as a matter of course, because it costs us nothing and it is frequently the difference between a claim being accepted and declined. Read more on storm damage and insurance work.

None of that is insurance advice, and your policy wording is what governs. Read the product disclosure statement or call your insurer.

Do plumbers fix roof leaks?

Sometimes, and it depends what is leaking. Roof plumbing, meaning gutters, downpipes, flashings and metal roofing, sits with a licensed roof plumber. Tiled roof work, meaning lifting tiles, battens, sarking, bedding and pointing, sits with a roof tiler. Plenty of leaks touch both, which is why it is worth asking whoever you call which licence they actually hold before they arrive.

Ours is NSW licence 488966C and it is publicly verifiable.

Common questions

Can a leaking roof be repaired, or do I need a whole new roof?

Most leaks are repairable. A full replacement is the right answer when the roof is at the end of its life across the board, not when one section is failing. The job above is the ordinary case: one section fixed properly, the rest of the roof left alone.

How much does a roof leak repair cost in Sydney?

A targeted repair, where a defined section is stripped back, sarked and re-laid rather than the whole roof, typically runs $4,000 to $6,000. A single cracked tile is far less. A full replacement is many times more. What moves it is how much roof has to come off, whether the battens underneath are sound, access and pitch, and whether the cause is one entry point or several.

How long does a leak repair take?

Finding the cause is usually the same visit. The repair itself depends entirely on what is behind it. A cracked tile is minutes. Stripping back a section, sarking it and re-laying is a day's work.

Why does my roof only leak sometimes?

Almost always wind direction or rain intensity. Leaks that need driving rain from one particular direction usually point at flashing, or at a section of roof below the pitch its tiles are rated for.

Should I just seal it myself?

Sealant over the visible symptom is the most common way a small leak becomes an expensive one. It blocks the path the water was taking and sends it somewhere else inside the roof, usually somewhere you will not notice until the damage is worse.