Asbestos-cement roofing was standard on Sydney garages, carports, sheds and post-war housing. Most people want it gone and replaced in the same visit, which is how we scope this work by default — a roof that comes off and does not go back on is a bigger problem than the asbestos was.
Why roof sheeting is the material most often misjudged
An asbestos-cement roof spends its whole life in the weather. Rain, sun and forty years of thermal cycling break down the cement matrix that holds the fibres in, and the surface starts to chalk and shed. A roof that was solidly bonded when it went on can be assessed as friable by the time it comes off — and friable material is Class A licensed work with mandatory air monitoring and a clearance certificate, at a very different price.
This is the single most common reason roof quotes differ from each other. If one price is far below the others, the likely explanation is that it has been scoped as intact bonded sheeting when the roof is not intact bonded sheeting any more. Ask what the material was assessed as.
The practical rule for you, before anyone quotes: stay off it. Weathered asbestos-cement roofing is brittle, and roof sheets are not a walking surface even when they are new. Falls through degraded sheeting injure more people each year than the fibres do.
The two things never to do to an asbestos roof
- Never water-blast it. High-pressure cleaning of an asbestos-cement roof is prohibited work in NSW and it is the fastest way to put fibres into the air, into the gutters and into the soil around the house. It also contaminates the downpipes, the tank if you have one, and the garden bed the runoff lands in — turning a roof job into a soil job.
- Never wire-brush, sand or grind it. Same mechanism, smaller scale.
If a roof cleaner has offered to “clean up” an old fibro roof, that is the wrong trade for the job.
Removal and replacement in one visit
We scope this work as removal plus re-roof by default. The sequence on a typical single-storey garage or house roof:
- Assessment and measure. Sheeting type, condition, fixings, and whether battens or purlins need replacing too — they usually do on a roof this old.
- Controls and set-up. The area below is isolated, ground sheeting goes down, and gutters are protected so debris is captured rather than washed away later.
- Careful strip. Sheets are unfixed and lifted whole wherever possible rather than broken up. Whole sheets mean fewer fibres and less waste weight.
- Wrap, load, dispose. Double-wrapped and labelled, then transported to a facility licensed to accept asbestos waste. Roof loads are heavy, and disposal is charged by the tonne.
- Re-roof. New sheeting on, flashings and capping done, building closed in before we leave.
What drives the roof price
Area is the obvious one. The less obvious ones are height and pitch (a two-storey or steep roof needs scaffold and edge protection), access (whether a truck can get near the load-out point, or every wrapped sheet is carried down a side path), condition (see friable, above), and the new roof — the replacement sheeting is a real cost sitting alongside the removal, and it is worth having both itemised.
Published Sydney ranges for asbestos roof removal and a full breakdown of what moves the number are in the cost guide.
Storm damage
Storm-cracked asbestos roofing is the one version of this job that is genuinely urgent, because the material is already broken and the debris is already loose. Close the area off, keep people and pets out, do not sweep anything up, and photograph it from a distance for the insurer before anything is touched.
