The short answer
You need to find out whether the garage roof contains asbestos before any work disturbs it, and that usually means a laboratory test on a small sample rather than a full survey. If the roof is corrugated grey sheet from before the end of the last century, or you cannot tell what it is, test first. A modern roof with paperwork showing it is asbestos-free needs no test.
Which garage roofs are worth testing
Age and appearance tell you where to start. Asbestos cement was used for corrugated roof sheets, flat panels, soffits, gutters and fascia boards, and it turns up on garages, sheds, outbuildings and lean-tos built over many decades. A garage with corrugated grey sheets, particularly one that is weathered, patchy with moss or fixed with large-headed bolts, is a candidate. So is a garage with flat grey boards under the eaves.
A garage with a pitched roof of clay or concrete tiles, a metal box profile roof, a felted flat roof or a recent rubber membrane is far less likely to contain it, though old felt and bitumen products occasionally included asbestos fibre. If the garage was built or re-roofed recently and you have an invoice or building control certificate describing the covering, that paperwork may settle the question without a test.
If the answer is not obvious, treat the roof as suspect until it is proved otherwise. A test is quick and a cheap way to avoid guessing, whereas a wrong guess can be costly in the other direction.
Test, survey or neither
The words get mixed up, so it helps to separate them.
- A sample test. A small piece of the material is taken, sealed and sent to a laboratory that identifies whether it contains asbestos and which type. For a single garage roof this is usually all that is needed.
- A survey. A person inspects the building, notes every material that might contain asbestos, and reports on its condition. It makes sense when there is more than one suspect material, for example a garage that has asbestos cement sheets, a textured ceiling and flue pipes, or where building work will go further than the roof.
- Neither. If documents show the covering is newer and asbestos-free, and you can see nothing that points the other way, the roof can be treated as ordinary.
Even a test is a small disturbance, so it should be taken carefully. The sample is cut with minimal breakage from a point that will be replaced anyway, and the place is sealed afterwards. This is not a job to attempt with a hacksaw and a carrier bag.
Why it comes before the work, not after
The sequence matters because the method of work depends on the answer. Careful removal of asbestos cement sheets, lifted whole and not broken, follows one set of precautions. If the job will smash the sheets and leave heavy dust and rubble, the work becomes notifiable under the Health and Safety Executive's guidance on non-licensed work, which you can read on the HSE website. Knowing which situation you are in beforehand decides how the job is planned, what protection is used and where the waste goes.
Starting first and asking afterwards is the usual mistake. A roofer who begins to cut sheets with an angle grinder, or a householder who removes a sheet with a crowbar, may release fibres before anyone knows what the material is. A test first removes that risk, and it also protects the people nearby: neighbours, children and anyone parking in the garage.
It also affects the price. Asbestos removal and disposal costs more than ordinary strip-out, so knowing the answer before you request quotes keeps the figures comparable. For orientation, MyBuilder (2026) reports asbestos removal averaging about £2,000, with around £50 per square metre for general removal, as a typical UK range. Your fixed quote follows the survey.
When the roof is already damaged
A cracked, holed or collapsing sheet changes the order of priorities. The first aim is to avoid making more dust, so leave the sheet, keep people away and do not brush or hose it. Testing is still useful, but it is not the first thing to do with a roof that is falling in.
Our page on a broken asbestos roof sheet sets out the do-not list and the main routes. Where the damage is slight and the roof is otherwise sound, the answer may be careful whole-sheet removal. Where several sheets have gone, replacing the lot is normally a better use of money than patching.
Roofs under fallen branches, hail damage or years of pressure washing often look worse than they are, or sometimes better. The surface tells you little. What counts is whether the sheet is whole, dry and firmly fixed, or whether it is breaking up.
Gutters, soffits and the rest of the garage
Asbestos is not limited to the roof sheets. Garage gutters made of grey asbestos cement are a familiar sight, as are soffit boards, barge boards and small panels under the eaves. A new roof on an old garage often means these parts are disturbed too, because they are fixed to the same timbers or sit beside the sheets you are replacing.
Before any work, walk around the building and note every grey, brittle-looking component. If you are fitting new guttering, our page on garage gutters explains what the run needs, and it is worth testing the old gutter before it comes off. The same goes for the fixing brackets and any flue pipe that goes through the roof.
A conversion or extension is a bigger case. If the garage is to be changed, it is more likely that a survey, not just a sample, is the right step, because the work reaches the ceiling, walls and floor as well as the roof.
Doing it in the right order
Put together, the order is sensible and short. Look at the roof and decide whether it could be asbestos. If it could, or you cannot tell, have a sample taken and analysed. Get the result in writing before asking for quotes. If it is asbestos, choose between leaving it alone, replacing it with a different sheet or going further with a new roof structure. If it is not, the work proceeds as for any other garage roof.
We can help with that decision on your own garage. Our survey looks at the roof, the frame and the parts around it, and we explain what we see and what we think should be tested. The fixed price comes in writing afterwards, and where removal is part of the job we say how the waste will be handled. Our garage roof replacement page covers the service as a whole, and the number to ring is 01225 285181.
