Is my garage roof asbestos, and what am I allowed to do with it?
Corrugated garage roofs, flat sheets, downpipes and soffits from before 1999. How to recognise likely asbestos cement, why it is treated differently from insulating board, and what the rules actually say.
- Difficulty
- intermediate
- Time
- 10 min
- Read
- 5 min
- Safety
- restricted
Short answer
Asbestos cement is a hard, brittle, grey material with asbestos fibres bound into cement — corrugated garage and shed roofs are the commonest example, along with flat sheets, gutters, downpipes, flues and cold water tanks. It was used up to 1999. Left sound and undisturbed it is low risk. Breaking it, drilling it or cleaning it with a pressure washer is what makes it dangerous.
This is the asbestos-containing material a British householder is most likely to meet, and the one most likely to be treated casually because it looks like ordinary cement sheet. The right response is neither panic nor a jet wash, and the distinction between this and the more dangerous insulating board is worth understanding.
Safety
Step by step
- Learn where it turns up.Corrugated roof sheets on garages, sheds and outbuildings. Flat sheets used as soffits, panels and partitions. Gutters and downpipes. Flue pipes. Cold water tanks in lofts. Some artificial slates. Almost anywhere a cheap, weatherproof, fire-resistant sheet was wanted.
- Use the age as your first filter.Asbestos in construction products was progressively banned and all use ceased by 1999. A building or a component from before then may contain it; one demonstrably after does not.
- Recognise it by feel and appearance.Hard, brittle, and dense, mid-grey when weathered, often with a slightly fibrous look at a broken edge and a smooth face on one side. It does not dent, and it snaps rather than bending. Modern fibre cement looks very similar, which is exactly why age matters.
- Understand why it is treated differently from insulating board.The fibres are locked into a dense cement matrix, so an undisturbed sheet releases very little. Asbestos insulating board is soft and lightly bound and releases far more when disturbed, which is why it sits in a higher risk category and generally needs a licensed contractor.
- Know what the rules say about removal.HSE treats removal of asbestos cement as non-licensed work where the material is in reasonable condition and can be taken down whole without breaking up, and where the worker has had appropriate information, instruction and training. Where it is substantially damaged or broken up, it becomes notifiable non-licensed work.
- Know what is never acceptable.Power tools of any kind, dry sweeping or vacuuming with a domestic vacuum, breaking sheets to fit them in a skip, pressure washing a roof, and putting any of it in household waste. Each of those turns a bound material into airborne fibres.
- Understand disposal.Asbestos waste is hazardous waste. It is double wrapped in heavy polythene, labelled, taken by a registered waste carrier, and received at a site licensed to take it. Many councils accept small quantities from householders by appointment, and the conditions vary — ring first.
- Decide honestly whether it needs to go at all.Sound asbestos cement that is not being disturbed is generally best managed in place. Painting a sound sheet with a suitable coating stabilises the surface. The point at which removal is right is when it is broken, badly weathered, or in the way of work that would disturb it.
Tips
- If you are buying a house with an asbestos cement garage roof, that is normal and not a reason to walk away. It is a reason to know what it is, not to disturb it, and to price its eventual removal into any plan that involves the garage.
- Testing is inexpensive relative to guessing. UKAS-accredited laboratories analyse a sample, and taking the sample safely is itself a task with a method — many labs and surveyors will do both.
- Moss and lichen on an asbestos cement roof are cosmetic. Removing them with a pressure washer is the single worst thing anyone routinely does to this material.
Common mistakes
- Pressure washing an asbestos cement roof — It strips the weathered surface and blasts fibres and contaminated water over the garden and the neighbours. It is specifically warned against, and it is common.
- Breaking sheets to fit them into a skip — It converts a bound sheet into fibres and debris, and it is illegal to dispose of asbestos in general waste. Sheets come off whole and go away wrapped.
- Drilling it to fix something to it — Drilling releases fibres directly into the air at head height. There is almost always an alternative fixing point, and if there is not, the answer is not to drill it anyway.
- Assuming a modern-looking sheet is safe — Modern fibre cement is visually very similar. Where age is uncertain, treat it as asbestos until it has been tested — that is the standard precautionary approach.
If it doesn't work
A cracked or holed asbestos cement roof sheet
Cause: Age, impact, or someone walking on it — Fix: Do not patch it with anything that requires cutting or drilling. Damaged asbestos cement is the point at which removal becomes the right answer, and it is a job to have quoted.
Debris and broken pieces on the ground under an old roof
Cause: A deteriorating sheet shedding material — Fix: Do not sweep it up dry and do not vacuum it with a household vacuum. Dampen it, and get advice — this is the situation where a competent contractor is worth the money.
You have already drilled or cut something that may have been asbestos cement
Cause: Identification after the fact — Fix: Do not sweep or vacuum. Dampen the debris, keep people out of the area, and take advice from your local authority environmental health team or a licensed contractor. A single short exposure is a low risk, and the sensible response is to stop and clean up properly rather than to worry.
Questions people ask
Can I remove my own garage roof?
HSE's position is that asbestos cement removal is non-licensed work where the material is in reasonable condition and can be removed whole, and where the person doing it has had appropriate training. For most householders that training is the missing part, and the practical answer is to have it done. It is not a job to attempt from a video.
Is asbestos cement dangerous just sitting there?
Undisturbed and in sound condition, the fibres are bound in the cement and it releases very little. The risk comes from disturbing it. That is why management in place is a legitimate and common approach.
What is the difference between this and artex?
Textured coatings such as artex contained a small proportion of asbestos and are a different material with their own guidance. GuideHQ has a guide on testing artex. Both share the principle that the danger is in the disturbance.
Do I have to declare it when selling?
There is no general obligation to remove asbestos from a home, and the standard property information forms ask about known issues. Being straightforward about a known asbestos cement garage roof is normal and does not usually affect a sale.