How terracotta differs from concrete
Concrete tiles get their colour from a surface coat that fades. Terracotta's colour is fired into the clay, which is why an old terracotta roof can come up close to new after a good clean.
Glazed terracotta has a hard, shiny fired finish that paint struggles to grip. Unglazed terracotta can be painted, but Monier doesn't recommend it, because once it's painted it needs recoating from then on.
The catch is that clay is brittle. The NSW Government's heritage guidance says to avoid walking on brittle roof tiles, and a cracked tile can't be pushed back into shape like a dented sheet.
How long a terracotta roof lasts
Sources disagree. Monier says it isn't uncommon for terracotta tiles to give more than a century of service. The NSW Government's heritage inspection schedule is more cautious, giving terracotta roof coverings a life expectancy of 40 years and suggesting an inspection every 7 years.
Either way, age alone isn't a reason to replace a sound terracotta roof. The same heritage schedule advises against replacing original roof coverings unnecessarily.
Matching tiles on an older home
Federation houses, built about 1890 to 1915, typically had terracotta tile roofs, and the City of Cockburn lists Marseilles tiles among the usual roofs on Perth's Inter-War bungalows. Patterns from those eras often aren't made any more.
A roofer will often source reclaimed tiles from a salvage yard, or take tiles from a hidden slope and put any odd ones there instead. Some makers can help too: Bristile says it can source tiles to match an existing roof from a photo or a sample.
What a terracotta restoration involves
A gentle clean
Monier says moss and lichen grow more often on terracotta than on concrete, especially unglazed, but only on the surface. It strongly advises against pressure washers on roof tiles, so ask for a treatment and a gentle wash instead of a blast.
Replace cracked and slipped tiles
Each broken tile is swapped for a matching one, and slipped tiles are nudged back into line. On a very old roof, a good roofer allows for a few extra breakages in the quote.
Rebed and repoint the ridges
Ridge and hip mortar is renewed, with pointing in a colour that suits the clay. On a roof that won't be painted, that colour stays on show, so agree on it first.
Skip the paint, usually
Monier says terracotta doesn't need respraying because its colour is baked in. Paint is only worth considering on a roof so patched and mismatched that it can't look right any other way.
What's safe for you to do
You can
- Look for cracked, slipped or missing tiles from the ground with binoculars
- Hang on to any spare tiles in the garage or under the house, because they're a perfect match
- Ask your council whether the house is under a heritage overlay
Leave to a roofer
- Every part of the work up top, because terracotta cracks underfoot
- Cleaning without damaging old clay
- Finding and fitting matching tiles
Where we'd start
We'd ask for a quote for the clean, tile replacement and repointing, with no paint. On unglazed terracotta, that alone often brings the roof back. Ask each roofer how they'll clean without a high-pressure blast, where they'll find matching tiles, and whether they've allowed for breakages.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.
