Is it real slate, or asbestos cement?
From the late 1800s to the 1980s, asbestos cement 'slates' and shingles about 4 mm thick were made in Australia, often to replace real slate while keeping the look. They were sold as Fibrolite, Durabestos, Tasbestos, Endurite and Hardie's Shingleplank, in greys, brown, charcoal, red and russet. ASSEA, the federal asbestos agency, says some made between the mid 1950s and 1968 might contain blue asbestos, and only a NATA accredited lab test can confirm what's there. Until you know, nobody should drill, cut, water-blast or walk on it, and leave the gutters alone too, because they're likely to hold asbestos debris.
What natural slate offers, and what we can't tell you
Slate is natural stone split into thin pieces and fixed to battens. A NSW Government heritage inspection schedule puts its life expectancy at 50+ years, longer than the figures it gives for terracotta or steel, and suggests checking every 7 years for slipped, cracked, broken or porous slates.
That's close to all the independent detail we've found on slate, so this page is short on purpose. We haven't found reliable upkeep advice beyond that schedule.
The same schedule offers three rules that suit slate well: avoid walking on brittle roofing, avoid mixing materials that react with each other, and don't replace original roofing unless you must.
Slate against tile and steel
| Natural slate | Terracotta tile | Colorbond steel | |
|---|---|---|---|
| Life expectancy (NSW heritage schedule) | 50+ years | 40 years | 20 to 40 years for steel roofs |
| Who repairs it | A roofer who has worked on slate | Most tile roofers | Most metal roofers |
What to ask a slate roofer
- Have you worked on natural slate before, and can I see a past job?
- How sure are you it's real slate? If there's doubt, will you arrange testing first?
- Will repairs use matching slate, and where will it come from?
- Will you check the flashings and gutters on the same visit?
Your part, and the slater's
You can
- Look from the ground for slipped or missing slates after strong wind
- Leave the gutters alone until you know it isn't asbestos cement
Leave to a roofer
- Walking on slate, which is brittle
- Refixing or replacing slates
- Any work at all until asbestos is ruled out
What we'd do first
We'd settle the asbestos question before anything else, with a licensed asbestos assessor and a NATA accredited lab. If it's genuine slate, we'd repair rather than replace, using a roofer who has done slate before. A sound slate roof is worth keeping, and the NSW heritage guidance says the same.
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.