Don't break off a piece to check
Leave sampling to a professional. Snapping off a corner, drilling or scraping releases fibres, and ASSEA, the national asbestos agency, records cases of people falling through or off asbestos roofs during maintenance. Stay off the roof, and keep children and pets away from it and from any broken pieces on the ground.
Start with the age of the house
Age is the best first clue. ASSEA says a house built or renovated before 1990 probably has some asbestos, and asbestos was banned outright in Australia in December 2003. SafeWork SA goes further for older homes, saying one built or renovated before the mid-1980s is highly likely to contain asbestos products.
A newer house can still have an older shed or carport, and an older house may have been re-roofed since. The contract of sale, council records or a previous owner can sometimes tell you when the current roof went on.
Clues that point to asbestos cement
- Grey or painted corrugated cement sheets with wide, deep ridges, often called Super Six
- Thin, flat 'slates' or shingles about 4 mm thick, in greys, charcoal, brown or red
- Cement ridge capping, roof ventilators or a ventilating ridge on an older roof
- Cement gutters or downpipes
- Flat cement sheet lining under the eaves or on the gables
- An old cement skylight surround or roof manhole
- A shed, garage or carport roofed in cement sheet
Is it Super Six, or only something that looks like it?
Super Six was a Hardies corrugated sheet from the mid 1920s, with seven wide, deep ridges about 5.7 inches apart, and the name stuck to almost all corrugated asbestos cement roofing. ASSEA says these sheets averaged around 15% asbestos and were also sold as Fibrolite, Durabestos, Fibrock and Tasbestos, among other names.
The catch is that Hardies stopped using asbestos around 1983 but kept selling a non-asbestos Super-Six until at least 1992, and the two look alike. ASSEA says identical sheets that aren't stamped asbestos-free should be treated with caution until tested. Our Super Six guide goes into more detail.
Old 'tiles' can mislead too. ASSEA's roofing product guide lists asbestos cement slates and shingles, and bituminous coated imitation tiles, among products used on Australian roofs. It says cement slates made between the mid 1950s and 1968 might contain crocidolite, the blue asbestos. EPA Victoria includes roofing tiles in its list of products that can contain asbestos.
How to find out for sure
Note the age and the materials
Write down when the house was built, any renovations you know about, and which parts of the roof, eaves and gutters look like cement sheet. Photos taken from the ground help whoever comes to look.
Run the quick check
Our asbestos checker asks two questions about age and appearance and tells you whether a test is worth arranging.
Have a professional take a sample
A licensed asbestos assessor or removalist can take a small sample safely and seal the spot afterwards. In the ACT, only a licensed asbestos assessor can identify asbestos.
Get it tested at a NATA-accredited lab
ASSEA and Queensland's asbestos authority both say laboratory testing is the only way to confirm it. Ask for the result in writing and keep it with your house records.
Decide what happens next
If it's asbestos and in good shape, leaving it alone may be fine. If it's cracked, brittle or due for replacement, plan for licensed removal and a new roof.
If it is asbestos, what are your options?
Leave it alone. ASSEA's view is that asbestos that's sealed, undamaged and left undisturbed isn't necessarily a danger to the people living with it. That rules out cleaning, drilling, cutting and walking on it.
Seal it. ASSEA suggests keeping asbestos materials in good condition with paint or sealants, as long as nobody cleans them first with high-pressure water or abrasives. Our guide to painting an asbestos roof explains when that's worth paying for.
Replace it. ASSEA says asbestos cement roofs are in the poorest condition of any asbestos still in buildings, and they get more brittle with age.
Things people don't expect
Gutters under an asbestos cement roof collect fibres washed off by rain, and ASSEA says that debris should be treated as friable, the crumbly, higher-risk kind. That's a job for a licensed removalist, not a weekend with a ladder. ASSEA also advises against using run-off from these roofs for drinking, washing or bathing.
Insurance and inspections may not help. ASSEA warns policies can exclude asbestos or fall short if it's damaged, and that pre-purchase building inspections generally don't cover it.
Storms can crack old sheets. ASSEA warns against hosing asbestos debris with high-pressure water after storms and floods. For a storm emergency, call the SES on 132 500 and tell them the roof may be asbestos.
What you can do, and what needs a professional
You can
- Find out when the house and the roof were built
- Look and take photos from the ground
- Use our asbestos checker
- Keep everyone off the roof and away from broken pieces
- Arrange a professional sample and a lab test
Leave to a roofer
- Taking the sample, by a licensed assessor or removalist
- Any cleaning, painting or repairs on a roof that might be asbestos
- Clearing gutters under a cement sheet roof
- Removal and disposal, by a licensed asbestos removalist
Our first move
If the house was built before 1990 and the roof or eaves look like cement sheet, we'd treat it as asbestos straight away: nobody on it, no cleaning, no drilling. Then we'd pay for a proper sample and lab test before spending a cent on repairs. Knowing for sure changes every quote you'll get, and it's far cheaper than guessing wrong.
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.