Drummy Tiles and Hollow Roofs: Warning Signs in Fleurieu Homes

Walk past a row of tile roofs in Port Elliot and you can hear which ones are hollow before you look up. Drummy tiles are the most obvious defect on most older coastal roofs, and they’re routinely ignored — because nothing looks wrong from the street.

A drummy tile is a roof tile that’s cracked, slipped or broken and no longer sheds water properly. It’s named for the sound it makes, not for what it’s doing to the roof underneath. And what it’s doing to the roof underneath is the whole point.

Safety first. Nothing in this post involves climbing onto a roof or walking on tiles. Every check described is done from the ground or from within the roof space, accessed through the normal manhole. If you want tiles checked properly, that’s what an inspection is for. Don’t go onto a coastal tile roof — they’re slippery when wet, brittle with age, and the fall risk isn’t worth a thirty-second answer.

What drummy tiles actually are

A drummy tile is one that has lost its weatherproofing, usually through:

• Cracking — from age, wind, foot traffic from previous repairs, or a tree branch.
• Slipping — the tile has moved off its seating, opening a gap at the head or the overlap.
• Broken or chipped pieces — often visible only as a different silhouette against the sky.
• Lime blowout or erosion of the bedding — the mortar or foam under the tile has crumbled away, so the tile sits proud or drops back.

It’s important to say what a drummy tile is not: it’s usually not a missing tile. A roof with a gap in it’s obvious and gets fixed. A roof full of slipped and cracked tiles that are still there, still look broadly intact from the ground, and are quietly letting water in at every wind-driven rain — that’s what gets missed.

The three tests

1. Tap, from the ground

A sound tile rings when tapped. A cracked or slipped tile gives a dull, flat, hollow sound.

This can be done with a long pole from the ground, at the eaves, or — where there’s no access and you would otherwise be reaching — it’s a test that’s genuinely better done by someone with the equipment and the judgement. The point of listing it’s that it’s the most reliable cheap test available and it requires no access to the roof at all.

2. Visual, from the street

Look at the roof line and the surface from ground level with binoculars, and check for:

• Silhouette differences. Slipped tiles sitting proud or dropped back break the line of the course. Against the sky this is often obvious.
• Gaps showing light or shadow through the tile line, especially on the sunlit side.
• Mortar or bedding missing beneath the tile edges, visible as a dark line.
• Ridge and hip tile damage — cracked or slipped ridge caps are the most common entry point.
• Debris in the gutters — tile fragments and sand washed off the roof collect and block drainage.

3. Roof void, from inside

This is the test that tells you whether it matters. Entering the roof space through the normal manhole and looking at the underside tells you what the roof has actually been doing. It’s covered in the next section.

The three tests together are the point: the first two tell you the roof is damaged, and only the third tells you what it has cost you.

Why coastal roofs fail faster

Three pressures stack up on the same roof.

Wind. The Fleurieu gets sustained coastal wind with gusts. Wind lifts and flexes tiles, and it drives rain sideways under laps and ridge lines. Wind is the single biggest difference between a coastal roof and an inland one.

Salt. Salt-laden air attacks fasteners, ridge fasteners and any exposed metal, so the things holding tiles down are themselves degrading — which links directly to salt corrosion of roof sheeting, gutters and tie-downs.

UV and heat cycling. Strong sun degrades the bedding mortar and sealant, and repeated heating and cooling cycles expand and contract tile and metal at different rates, cracking what’s fastened too rigidly.

None of these is dramatic on its own. Together, over decades, they’re the reason roof condition is one of the most common findings on an older coastal property.

What a roof void inspection catches

Looking under the roof tells you what the tiles have been doing, and it’s the difference between a maintenance item and a structural one.

Water entry. Water getting in through slipped or cracked tiles shows as staining, damp or discolouration on the sarking between or under rafters, and on the ceiling below. Fresh water entry and old, dry staining look different, and the difference tells you whether the problem is current.

Timber decay. Where water has been landing, the timber it lands on can deteriorate. This is the serious finding. Rafters that have lost section, or that are soft, fibrous and dark when probed, are a structural matter — not a tiling matter, and not something to be fixed by replacing tiles.

Sarking condition. The membrane or sheeting under the tiles. Perished or torn sarking, or sarking with large gaps, means the roof has never had a real weatherproof layer beneath the tiles — which is common on older roofs and changes the meaning of any tile defect above it.

Insulation and ventilation. Wet or displaced insulation, and inadequate ventilation that traps moisture in the cavity.

This is why a roof that looks like it just needs some tiles replaced can turn out to need a different conversation entirely.

Repair or monitor

Not every drummy tile needs replacing tomorrow. The decision depends on how many, where, and what’s happening underneath.

Monitor is reasonable where a small number of tiles are affected, there’s no water entry visible inside, the sarking is intact, and the roof is otherwise sound. That’s a legitimate outcome and an inspection should say so plainly rather than manufacturing urgency.

Repair is warranted where water entry is evident, tiles have slipped enough to open the roof up, ridge and hip capping is compromised, or the damage is progressive.

A different conversation where the timber underneath has decayed or the sarking has perished. At that point the roof isn’t a tiling job, and the framing needs assessing properly before anyone prices the tiles.

A hollow-sounding roof is one of the nine defects to check before offering on a coastal home — see the full list in buying a coastal home in SA. Our combined inspections cover roof, roof void and structure across Victor Harbor and the Fleurieu. Get a quote rather than climbing up yourself.

Frequently asked questions

What does a drummy tile sound like?

A sound concrete or clay tile gives a sharp ring when tapped, because the tile and the roof beneath it act together. A cracked or slipped tile gives a dull, flat or hollow sound, because the tile is no longer bonded or seated against anything solid. That difference is why tapping is such a useful test — but it only tells you the tile is compromised. It can’t tell you what the roof underneath is doing, which is why it’s paired with a look inside the roof space.

Can I walk on my roof to check the tiles?

No. Don’t walk on a coastal tile roof to check it. Tile roofs are slippery when wet and brittle with age, and a cracked tile underfoot can give way. Every check in this article can be done from the ground or from inside the roof space. If you need the tiles properly assessed, that’s what a roof inspection is for — and it’s a cheap answer compared to a fall.

Are drummy tiles a problem in an old coastal house?

Common ones are. On an older coastal property they’re one of the most frequently seen defects, driven by wind, salt and UV acting together over decades. Whether they matter depends on how many are affected, whether water is getting in beneath them, and what that water has done to the timber and sarking above the ceiling. The tiles are the visible symptom; the roof space is where the answer is.