Asbestos Garage Roof Removal: The Rules, and the DIY Line

Asbestos garage roof removal sits in an awkward gap in the law. Those grey corrugated sheets on tens of thousands of British garages and sheds are almost always asbestos cement, and work on asbestos cement is non-licensed work, which means a homeowner is not breaking any law by taking their own garage roof down. That is very different from it being a good idea, and the gap between “legal” and “sensible” is where people get hurt.

This page covers how to tell what you have, what the Health and Safety Executive actually requires, the things that turn a low-risk job into a dangerous one in seconds, and the honest test for whether to do it yourself. The short version: if there is any doubt about what the material is, get it tested before anyone touches it.

How to recognise asbestos cement

Asbestos cement is a mix of cement with asbestos fibres, usually chrysotile, bound into a hard sheet. On a garage it typically appears as corrugated sheeting, sometimes with matching ridge caps, gutters and downpipes.

Signs you are looking at it:

• Grey, cement-like appearance, often weathered to a mottled green or black with moss and lichen
• Corrugated profile with a regular wave, fixed through the crowns with hook bolts or screws
• Brittle rather than flexible, and noticeably heavier than a modern fibre cement or plastic equivalent
• A garage or shed built before the late 1990s

The date matters. Asbestos was progressively banned in the UK, with the final prohibition on chrysotile in 1999. Anything built after that should be asbestos-free; anything before is suspect until proven otherwise.

You cannot confirm it by looking. Modern non-asbestos fibre cement sheets look almost identical, and plenty of garages have been re-roofed at some point. The only certain answer comes from a sample tested by a laboratory, which is inexpensive and takes days rather than weeks. If you are about to disturb it, and you are not certain, test it. Treating a non-asbestos roof as asbestos costs you a small fee. Treating an asbestos roof as ordinary sheeting costs a great deal more.

There is a second material to rule out. Asbestos insulating board, often used as a garage ceiling lining, soffit or fire panel around a boiler, is a much softer, lower-density board with a far higher fibre release. Work on insulating board usually requires an HSE-licensed contractor. The HSE task sheet for cement sheets is explicit that it does not apply if other asbestos materials such as lagging or insulating board are present, and the licensed route applies instead.

Why asbestos cement is treated differently

Asbestos in an undamaged cement sheet is locked into a hard matrix. Left alone, a sound asbestos cement roof releases very little, which is why the standard official advice for material in good condition is to leave it in place and manage it rather than remove it.

The danger is entirely in what you do to it. Every serious exposure from a garage roof comes from the same handful of actions:

Breaking or snapping sheets. Fibres are released the moment the matrix fractures.

Drilling, cutting, sanding or grinding. Power tools on asbestos cement generate enormous fibre concentrations and are prohibited in HSE guidance.

Pressure washing. People do this to clean moss off a garage roof and it is one of the worst things you can do: a high-pressure jet strips the cement surface, releases fibres and sprays contaminated water across the garden. We cover the wider problem in our guide to the risks of pressure washing a roof.

Walking on it. Asbestos cement roofs are always fragile and will not bear weight. Falls through fragile roofs kill people in the UK every year, and on a garage that is a fall onto a concrete floor.

Dropping sheets or using a rubble chute. Both shatter the sheet on impact.

If you can get the roof off without doing any of those five things, the fibre release is low. If you cannot, it is not.

What the HSE method actually looks like

The relevant guidance is task sheet a14, removing asbestos cement sheets, gutters and dismantling a small structure, which explicitly covers a shed or garage. It is worth reading in full before you decide anything, because it is short and it tells you exactly what a competent job involves.

The critical condition is at the top of the sheet: the method applies “as long as AC stays intact during removal”. If the sheets start breaking up and creating significant dust, the job becomes notifiable non-licensed work, which is a different legal category requiring notification to the enforcing authority, medical surveillance and record keeping. In practice that means a badly degraded roof that shatters as you lift it has just moved out of the scope of a homeowner job.

The method in outline:

Before starting. Confirm only asbestos cement is present. Arrange safe access, which usually means a mobile access platform rather than a ladder, because you must never stand on the roof. Restrict access to the area with tape and warning notices. Cover nearby surfaces with 500-gauge polythene taped to non-asbestos surfaces.

Protective equipment. Disposable hooded overalls, boots without laces (laced boots cannot be decontaminated properly) and respiratory protective equipment. Not a dust mask from a DIY shop.

Removal. Avoid or minimise breaking the sheets. Dampen fixings with a garden sprayer containing a wetting agent before removing them, and bag the fixings as asbestos waste. Where sheets are bolted, dampen and cut the bolts with a bolt cutter, avoiding contact with the sheet itself. Lower large pieces to the ground with straps or ropes, never drop them and never use a rubble chute. Stack the sheets carefully.

Wrapping. Double-wrap large pieces in 1000-gauge polythene sheeting sealed with duct tape and apply asbestos warning stickers. Small pieces go into an asbestos waste bag, which then goes inside a clear polythene bag, taped shut.

Cleaning up. Damp rags on the equipment and the area, check the bolt holes and fastener positions for debris, and bag the rags, the polythene and everything else as asbestos waste. Contaminated webbing and rope goes in the waste too.

Finishing. A visual inspection to confirm the area is clean. Clearance air sampling is not normally needed for this task.

One option the sheet raises that most people never consider: can you overlay the sheets with non-asbestos material instead of removing them? If the structure is sound, fixing new material to the existing purlins avoids the removal problem altogether. Avoid drilling through the asbestos cement if you go this route.

Disposal is where DIY jobs stall

Asbestos cement is hazardous waste, and you cannot put it in a skip, a household bin, or the back of a van to the tip without arranging it first.

Some council household waste recycling centres accept small quantities of double-wrapped asbestos cement from householders. Many limit the quantity, most require a booking, some charge, and a number do not accept it at all. This varies by council and it changes, so phone your own centre and confirm before you take a single sheet off. A garage roof is more waste than people expect, and a stack of double-wrapped sheets sitting in a garden while you work out where to take it is a bad outcome.

If your centre will not take it, you need a waste carrier registered with the Environment Agency, and hazardous waste must travel on a consignment note. Any contractor doing the removal should handle all of that as part of the job.

When to hand it to a contractor

Be honest about these five, and if any one of them is a yes, call someone in.

• The roof is already broken, cracked or has sheets missing
• You would need to work off a ladder rather than a platform, or the garage is attached to the house with an awkward junction
• There is any board, lagging or panel involved that is not plain cement sheet
• Your local recycling centre will not take the waste
• You are not confident you can lift a full sheet down without breaking it

A competent contractor should be able to show you a written plan of work for the job, evidence of non-licensed asbestos training for the operatives, waste carrier registration, and the consignment note for the disposal at the end. Ask for all four before they start, not after. Our guides on questions to ask a roofer and spotting rogue roofers apply here with more force than usual, because asbestos work is a favourite of doorstep traders who quote low and fly-tip the waste.

Once the roof is off, you are into a straightforward re-roof, and the options and costs are in our garage roof replacement cost guide.

Frequently asked questions

Can I remove an asbestos garage roof myself in the UK? Legally, yes. Asbestos cement is non-licensed work, so a homeowner may remove their own garage roof without a licence. It stops being a homeowner job if the sheets break up and create significant dust, which makes it notifiable non-licensed work, or if any asbestos insulating board is involved, which needs a licensed contractor.

How do I know if my garage roof is asbestos? You cannot tell by looking, because modern non-asbestos fibre cement sheets are near identical. Grey corrugated sheeting on a garage built before the final UK ban in 1999 should be treated as asbestos until a laboratory test of a sample says otherwise. Testing is cheap relative to the consequences of guessing wrong.

Is an asbestos garage roof dangerous if I leave it alone? An intact asbestos cement roof in good condition releases very few fibres, and the standard advice for sound material is to leave it in place and keep an eye on it. The risk comes from disturbing it: breaking sheets, drilling, cutting, sanding or pressure washing. Removal for its own sake is often the more hazardous choice.

Can I pressure wash moss off an asbestos garage roof? No. A high-pressure jet abrades the cement surface, releases fibres and spreads contaminated water across the surrounding area. It is one of the most damaging things you can do to asbestos cement and is prohibited in HSE guidance. If moss is the problem, the roof needs assessing rather than cleaning.

How do I dispose of asbestos garage roof sheets? Double-wrap large pieces in 1000-gauge polythene, seal with duct tape and apply asbestos warning stickers. Then check with your council’s household waste recycling centre, because acceptance, quantity limits, booking requirements and charges all vary and some centres refuse it. If they will not take it, you need an Environment Agency registered waste carrier and a hazardous waste consignment note.

What should an asbestos removal contractor show me? A written plan of work for the specific job, training records showing non-licensed asbestos competence, Environment Agency waste carrier registration, and the hazardous waste consignment note once the material has been disposed of. Ask for the first three before work starts. A contractor who cannot produce them is not the right contractor for this job.

Sources

• HSE asbestos essentials a14: removing asbestos cement sheets and dismantling a small structure
• HSE: asbestos essentials task sheets, A series
• HSE: asbestos frequently asked questions