What does an asbestos roof look like?

The common type is 'Super 6': a cement-sheet roof with wide corrugations about 6 inches (150mm) across; there's a rarer 'Mini-orb' profile with corrugations about 3 inches across. Asbestos roofs are almost never painted from new, so they weather to a distinctive mouldy black-and-white finish. They're usually low-pitch, on smaller roofs (up to about 120m²) with gable ends, and the sheets are brittle and heavy. Critically, it looks nothing like the grey loose-fill cellulose we pump in: these are hard cement sheets, not insulation.

Does Comfort Zone cellulose insulation contain asbestos?

No, and it's a common worry, so let me be clear. Our cellulose is recycled paper fibre treated with borax and boric acid, manufactured to the Australian Standard AS/NZS 4859.1 at our own factory. There is no asbestos and no formaldehyde in it. Asbestos was a hard cement sheeting product banned in Australia; our insulation is a soft, recycled paper blanket. They have nothing in common.

Can you insulate a roof that has asbestos sheeting?

Yes, and these are exactly the roofs batt companies say can't be done. We pump cellulose in from underneath by lifting a single sheet (even if there's no manhole), without disturbing, cutting or breaking the asbestos. Low-pitch fibro roofs get extremely hot in summer, so insulating under them makes a big difference. After more than 6,000 roofs I know how to work around them safely, but I'd never recommend anyone untrained move those brittle sheets.

What should I never do with an asbestos roof?

Never sand, grind, cut or drill it, because that releases the dangerous fibres. That means no cutting holes for roof vents or skylights. Don't collect drinking water off an asbestos roof. Asbestos is banned in Australia because the fibres get into your lungs and cause cancer. If sheets are breaking or you want to replace the roof, that's a job for a licensed asbestos removalist; in Queensland a licence is required to remove more than 10m² of non-friable asbestos. Until then, a sound asbestos roof that's keeping the water out is doing its job; you can insulate under it safely without touching the sheets.

Roof safety · how to identify it

Asbestos in your roof: what it looks like, and is it safe?

An asbestos “Super 6” fibro roof is a low-pitch, mouldy black-and-white cement-sheet roof with wide ~6-inch corrugations, and it looks nothing like the grey loose-fill insulation we pump in. Don’t cut, drill or disturb it; we can still insulate safely underneath it.

How to identify it

What an asbestos roof looks like.

The common asbestos roof is the “Super 6” profile, a hard cement sheet with wide corrugations about 6 inches (150mm) across. There’s a less common “Mini-orb” profile with corrugations about 3 inches across.

Almost never painted from new, so it weathers to a distinctive mouldy black-and-white finish.
Usually low-pitch, on smaller roofs up to about 120m², often with gable ends.
The sheets are brittle and heavy, so they can't be walked on or replaced like a tile.
It's a hard cement sheet, not a soft material, nothing like the grey cellulose we pump in.

The low pitch and that black mould make these roofs extremely hot in summer, which is exactly why insulating under them is worth doing.

A weathered grey corrugated fibro / Super Six asbestos-cement sheet roof

A classic Super 6 corrugated asbestos-cement roof: low pitch, weathered to a mouldy grey. Common on older Queensland homes, and the kind we insulate under without disturbing the sheets.

A red-painted corrugated fibro Super-6 roof seen from a distance in daylight with a rooftop solar hot-water tank, identification shot of a hard roof type — A real fibro Super 6 roof: wide ~6-inch corrugations, weathered, no cavity underneath. This is the look to watch for.

Close-up of a slotted flat-head screw and square washer fixing a painted fibro Super-6 roof sheet, paint flaking around the fastener — Flat-head screws and square washers like these are a dead giveaway you’re on an old fibro Super 6 roof.

The common worry, answered

Our cellulose insulation contains no asbestos.

People sometimes hear “fibre” and worry. Let me be clear: our cellulose is recycled paper treated with borax and boric acid, made to the Australian Standard AS/NZS 4859.1 at our own factory. There’s no asbestos and no formaldehyde in it. Asbestos was a hard, banned cement-sheet product; our insulation is a soft recycled-paper blanket. They have nothing in common. Here’s exactly what’s in our cellulose.

Important: your safety

What you must never do to an asbestos roof.

Asbestos is banned in Australia because the fibres get into your lungs and cause cancer. A sound asbestos roof that’s keeping the water out is doing its job. The danger is disturbing it.

Never sand, grind, cut or drill it, because that releases the fibres. (So no cutting holes for roof vents or skylights.)
Don't collect drinking water off an asbestos roof.
Don't walk on or try to move the sheets, as they're brittle and need two-person handling by people who know what they're doing.
Removal or replacement is a job for a licensed asbestos removalist; in Queensland a licence is required to remove more than 10m² of non-friable asbestos.

Authoritative guidance: asbestos.gov.au (the national Asbestos and Silica Safety and Eradication Agency), WorkSafe Queensland, and Safe Work Australia.

How we work with it

How we insulate under an asbestos roof, without disturbing it.

These are the roofs batt companies say can’t be insulated. We can, by pumping cellulose in from underneath, lifting a single sheet for access (even if there’s no manhole), without cutting, drilling or breaking the asbestos. The cellulose goes in as a seamless blanket from below, so the sheets are never disturbed.

A Super-6 fibro roof cavity filled with an even grey cellulose blanket after pumping, flowing into the eaves and around the timbers — A fibro Super 6 roof we pumped full of cellulose from underneath: an even blanket right out to the eaves, and not one sheet disturbed.

If your asbestos roof has a leak, it’s most often a cracked ridge cap or the screws starting to weep (the original tar on them dries and cracks over the years). Tar-backed aluminium foil tape is a good fix, better than silicone, which tends to peel off with the top layer of fibres. As always, no cutting or grinding.

See the other roofs we insulate that others say can’t be done →Our full training & safety standards →

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Asbestos in your roof: what it looks like, and is it safe?

What an asbestos roof looks like.

Our cellulose insulation contains no asbestos.

What you must never do to an asbestos roof.

How we insulate under an asbestos roof, without disturbing it.

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