Asbestos roof tiles, sheets and "super six": what is actually up there
Concrete and terracotta tiles are not asbestos products. Corrugated cement sheeting often is. And from the footpath the two questions get confused constantly.
If you are searching for asbestos roof tiles, the first thing worth knowing is that the asbestos roofing Australia actually has is usually not a tile at all. It is corrugated asbestos cement sheeting (the grey, deeply ribbed material most people still call by an old trade name, super six) screwed down over the rafters in long sheets.
Clay and concrete roof tiles are not asbestos products. Flat asbestos cement shingles and slates were made as well and do still turn up, mostly on older houses and outbuildings, but they are the minority case.
None of this is a confirmation, and this page is deliberately not one. Nobody can identify asbestos from the footpath, from a ladder or from a photograph. What the checks below do is tell you whether the question is live enough to be worth a sample, which is a different and much more useful thing.
Is it a sheet, a tile, or metal?
Three materials get called “roof tiles” in this conversation, and they behave completely differently.
| What it is | What it looks like from the ground | Asbestos question |
|---|---|---|
| Corrugated asbestos cement sheeting | Long grey sheets with large, widely spaced corrugations. Weathers chalky and pale, carries moss and lichen, edges look thick and blunt. Fixed through the crest of the corrugation with hook bolts or screws under a washer or cap. | Live. This is the classic Australian case, especially on houses, garages, sheds and carports of a certain age. |
| Corrugated steel (galvanised or coated) | Smaller, tighter corrugations. Rusts rather than chalking, and the cut edge is thin and sharp. Often a factory colour. | Not an asbestos product. But an old steel roof can sit directly over an older material, and the eaves lining underneath is a separate question. |
| Concrete or terracotta tiles | Individual interlocking tiles, heavy, laid in rows with mortared ridge capping. | Not asbestos. If a tiled roof raises the question, what prompted it is almost always something else in the roof: see below. |
The clue that separates sheeting from iron: the edge
At the gable end and along the gutter line you can usually see the edge of the sheet. Asbestos cement is a rigid board roughly six millimetres thick, and the edge reads as a blunt grey band. Steel is thin-gauge metal and the edge reads as a line.
Two more differences hold up from a distance. Asbestos cement goes chalky and white as it weathers and grows moss in the valleys of the corrugation, while steel rusts at the fixings and the laps. Asbestos cement also has its colour all the way through, so a chipped corner shows grey, not a bright metal scar.
A third clue is the corrugation itself. The asbestos cement profile has fewer, larger, more widely spaced ribs across the same width of roof than standard corrugated steel. Once you have seen the two side by side on a street it is hard to unsee.
Does the age of the house settle it?
It narrows it, and no more than that. Asbestos was taken out of Australian cement sheeting through the 1980s, and the total ban on manufacturing, importing and using asbestos products took effect on 31 December 2003. So what matters is the age of the material, not the age of the house. A 1950s house that was re-roofed in 2010 has a modern roof. A 1990s extension can carry secondhand sheets someone had in the yard.
The useful reading is: an original-looking grey corrugated cement roof on a house built before the mid-1980s is worth treating as though it contains asbestos until something says otherwise. That is not alarmism. It is the same conclusion a regulator would reach, and it costs you nothing while the roof is intact and left alone.
If the roof really is tiled, what is the question about?
When a tiled roof prompts an asbestos search, the tiles are usually not the reason. The materials to look at are the ones around and under them:
- The eaves lining. The flat sheet under the overhang is one of the most common asbestos cement products left on Australian houses.
- Gable infill and wall sheeting that meets the roof.
- An old flue or vent passing through the roof.
- Debris in the roof space: offcuts, broken sheet and dust left by earlier work, plus, in a small number of Canberra and NSW houses, loose-fill insulation with its own separate register and process.
What not to do once you suspect it
The material is not the danger; disturbing it is. So the honest advice is a list of things to stop doing rather than a method:
- Do not high-pressure wash it. This is the single worst thing you can do to an asbestos cement roof, and it is prohibited across Australian jurisdictions.
- Do not walk on it. Weathered sheets are brittle and give way, and falls through roofs are a leading cause of serious injury in this work.
- Do not cut, drill, sand or grind it, and do not let a tradesperson do so in passing while fitting an aerial, a solar bracket or a skylight.
- Do not sweep up or bin broken pieces with the household rubbish. Asbestos waste goes to a landfill licensed to accept it.
- Do not scrape the gutters out onto the garden. Gutter sludge under a weathered asbestos cement roof is part of the same question.
How the question actually gets answered
There are two legitimate endings. The first is to presume the material contains asbestos and behave accordingly. That is a recognised approach and, for an intact roof nobody is about to touch, often the sensible one. The second is a sample taken and analysed by a laboratory: only laboratory analysis settles it. Accreditation by the National Association of Testing Authorities is what gives you grounds to rely on the result.
What happens next decides which of the two you need. Leaving the roof alone rarely needs a certificate. Selling, renovating, mounting anything on it, or replacing it does. The class of licence the removal work requires, along with the small-quantity allowance a householder may work within, is set by the WHS regulator in your own state or territory. Those rules differ between jurisdictions, and a figure quoted for one state cannot be assumed to apply in another.
Frequently asked questions
Are concrete or terracotta roof tiles asbestos?
No. Clay and concrete roof tiles are not asbestos products. When a tiled roof raises the question, what prompted it is usually the eaves lining, gable sheeting, an old flue or debris left in the roof space rather than the tiles themselves.
How do I tell asbestos cement sheeting from corrugated iron?
Look at the edge at the gable or the gutter line. Asbestos cement is a rigid board about six millimetres thick and reads as a blunt grey band; steel is thin-gauge and reads as a line. Asbestos cement also weathers chalky and grows moss, where steel rusts, and its corrugations are fewer and more widely spaced.
What is super six?
It is an old trade name for a corrugated asbestos cement roofing profile that became the everyday word for the material in Australia. Not every sheet called super six is that product, and the name alone confirms nothing.
My roof is grey corrugated sheeting and the house is from the 1960s. Is it asbestos?
It is worth treating as though it is until something says otherwise, but nobody can confirm it by sight. Asbestos was taken out of Australian cement sheeting through the 1980s and banned outright from 31 December 2003, so what matters is the age of the material, not the house. A re-roof resets the answer.
Can I clean the moss off an asbestos cement roof?
Not with a pressure washer, which is prohibited and is the worst thing you can do to this material. Cleaning and coating a sound roof is a separate question with its own rules, and a roof that is already degraded is usually past the point where coating it makes sense.
Sources
What this page explains is based on these official sources. If you check one and it does not match what you read here, send it to us and the article gets corrected.
- Asbestos Safety and Eradication Agency. Asbestos Product Guide. What products contained asbestos and where they were used
- NSW Government. Asbestos in NSW. The NSW Government asbestos portal
- WorkSafe Victoria. Asbestos. Duties, licensing and safe removal