Asbestos in the roof: the parts that are not the sheets
A roof is not one material. It is several, fixed at different times by different tradespeople, and most of what gets missed sits at the joins rather than in the middle of a sheet.
Searching for asbestos in the roof almost always means one thing first: the main covering, the sheets overhead. That is the right place to start, and this site covers it in detail. The short version is that most Australian roof asbestos is corrugated cement sheeting, not a tile. And telling it apart from tiles and from metal is its own page.
What that page does not cover is everything else on the same roof that can be a separate asbestos cement product. A different tradesperson may have fixed it at a different time, and it deserves a completely separate answer.
None of what follows is an identification. Nobody can confirm asbestos from the ground, from a ladder or from a description on a page like this one: only laboratory analysis settles what a material is. And accreditation by the National Association of Testing Authorities (NATA) is what gives the result something to rely on. What this page does is widen the question from “is my roof asbestos” to the more useful one: which part of it, specifically.
A roof is at least five separate products
| Part of the roof | What it is | Why it is a separate question |
|---|---|---|
| The main covering | Corrugated cement sheeting screwed to the rafters, or in the minority of cases flat cement shingles. | Covered separately. See the identification page above. |
| Ridge and hip capping | The moulded piece that caps the join at the top of the roof and along the hips. Government product guides list moulded roofing accessories made in asbestos cement to fit the sheeting profile of the day. | Often replaced in a different material at a different time to the sheets it sits on: capping can be newer, or older, than the roof it caps. |
| Valleys and box gutters | The lining that channels water where two roof planes meet, or along an internal gutter. Frequently metal, but not always, and it sits directly under debris and leaf litter that nobody disturbs for years. | A part of the roof that is rarely inspected because it is not visible from the ground or from inside the roof space. |
| Barge boards and gable flashings | The trim at the roof edge, at the gable end, cut from flat cement sheet on many older houses. | Meets the wall cladding and the eaves lining at a corner that often gets painted over and never looked at again. |
| Vents, flue caps and roof penetrations | Small moulded fittings around an old flue, an extraction vent or an aerial mount. | Small, easy to miss, and often the thing a tradesperson drills straight through while fitting something newer. |
The roof space is a sixth, and it is different in kind
Everything above sits outside, exposed to weather and sun. What is above the ceiling is a separate case again: not because the products are always different. But because a roof space is unventilated and connected to the rooms below through the manhole, downlight cut-outs and exhaust fans. That page covers loose-fill insulation, flue lagging and the underside of sheeting on its own terms. And it is worth reading before anyone goes up there, not after.
Why splitting the roof up like this matters
Two practical consequences follow from treating a roof as several products rather than one. The first is dating: a re-roof, a repaired valley or a replaced barge board can each carry a different age to the sheets around them. So “the house was built in the 1990s” settles less than it sounds like it should.
The second is scope: a quote or an inspection that only mentions the main sheets. And says nothing about capping, valleys, flashings or the roof space, has not actually looked at the roof. It has looked at the largest and most obvious part of it.
What not to do while the question is open
This is a list of things to stop, not a method for anything:
- Do not clear a valley or box gutter with a pressure washer or a stiff broom. Scraping out compacted debris by hand disturbs whatever the debris is sitting on.
- Do not cut, drill or grind ridge capping, flashings or vent fittings to fit an aerial bracket, a solar mount or a new vent.
- Do not scrape old paint or moss off any of these pieces to see what is underneath.
- Do not treat a newer-looking part as proof the rest is newer too. A single replaced flashing says nothing about the capping next to it.
How the question actually gets settled
Two honest endings apply to every part of the roof on this list, the same as they apply to the sheets. The first is to presume the older-looking pieces are asbestos cement and leave them undisturbed, which costs nothing while nobody is working on them. The second is a sample, taken and analysed by a laboratory, with NATA accreditation behind the result.
Which pieces need which answer, and what a removal or repair of any of them would require, is set by the WHS regulator in your own state or territory. The rules and the small-quantity allowances differ between jurisdictions. And a figure that applies in one state cannot be assumed to hold in another.
Frequently asked questions
Does "asbestos in the roof" only mean the sheets?
No. The main covering is usually what prompts the search, but a roof also includes ridge and hip capping, valley and box gutter lining, barge boards and gable flashings, vents and flue caps, and the separate question of the roof space above the ceiling. Each is its own product with its own age.
Can the ridge capping be a different age to the roof sheets?
Yes. Capping is fixed and replaced separately from the main sheets, so a roof can have older sheeting under newer capping, or the reverse. The age of the house does not settle the age of any one part.
Is a valley or box gutter likely to contain asbestos?
It depends on the material used, which is not always visible without clearing the debris sitting in it: and clearing it is exactly the disturbance to avoid. It is worth treating as an open question rather than assuming it matches the roof sheets.
My roof sheets are newer, but the flashings look old. Does that matter?
Yes. A replaced section of sheeting does not mean the trim, capping or flashings around it were replaced at the same time. Each piece is worth its own look rather than a judgement based on the largest, most visible part of the roof.
Who can tell me for certain whether a roof part contains asbestos?
Nobody can from a description, a photo or a look from the ground. Only a sample analysed by a laboratory settles it, and accreditation by NATA is what makes that result dependable.
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