The short answer
Leave the sheet alone. Do not sweep, drill, scrub or pressure-wash it, keep everyone away from loose fragments, and arrange for a contractor who follows HSE rules on asbestos cement to look at it. A sheet that is cracked but whole is handled differently from one that is substantially broken up, because substantial breakage makes the job notifiable before it starts.
What to do in the first few minutes
Corrugated sheets on garages built before 2000 may be asbestos cement, and the safe habit is to treat them that way until a test says otherwise. Our guide on whether your garage roof is asbestos explains how to tell. A sheet that has cracked, slipped or dropped a corner is the moment that habit pays off.
Stop what you are doing. Do not pick up pieces with bare hands, do not sweep them into a pile, and do not reach for a vacuum cleaner, a leaf blower or a hose. Each of those turns a solid fragment into dust or carries it across the drive. Shut the garage door if the debris is inside, and mark off pieces lying in the garden with tape.
If the break is in the roof itself, do not climb up to look. Asbestos cement is brittle, and weathered sheets can give way under a knee or a ladder foot, which makes the damage far worse and puts you at risk of a fall. A photograph from the ground, taken on zoom, is plenty for a first conversation.
Cracked, holed or collapsed: where the HSE line falls
Lifting intact asbestos cement panels off a roof carefully is non-licensed work in HSE's terms, so long as nothing is smashed on the way down. Cement that has merely weathered counts too. A sheet with a hairline crack, a knocked corner or one small hole generally sits on this side of the line.
Things change once the material is substantially damaged or broken up, or when taking it off would break it up. HSE's own illustration is dropping an asbestos cement roof to the ground. Work like that is notifiable non-licensed work, shortened to NNLW. A garage where several sheets have snapped, where a tree limb has gone through, or where a whole run has sagged and cracked along the purlins is the sort of job that can land in that category.
Which side your roof falls on is a judgement for the person who inspects it, not a guess from the lawn. That is one reason a photographic survey comes before anyone quotes.
What notifiable work involves
Where work is notifiable, the employer carrying it out must notify the enforcing body ahead of the start, and HSE sets no minimum notice period. Two duties follow. The workforce needs a medical examination at intervals of no more than three years, and a register of the jobs, which doubles as a health record, is kept for 40 years.
None of that is for the householder to administer, but it makes a handy test of any firm you speak to. Ask: should the sheets prove to be badly broken, will you notify the work, and where does the waste go? A calm, specific answer is what you want. A shrug, or an offer to whip the lot down for cash on Saturday, is not.
Waste is the other half. Asbestos taken from a house or garage travels under a consignment note, completed by the contractor as waste producer. The paperwork is covered in our page on how asbestos waste is disposed of.
Keeping the rain out meanwhile
A broken sheet usually means a wet garage, and a wet garage tempts people to patch the hole. Resist screwing a board over it, smearing mastic into the crack or pinning a tarpaulin through the sheet. Every fixing disturbs the material, and a tarpaulin that flaps in wind rubs fibres loose from the corrugations.
A better stopgap is to shift belongings out of the drip line, cover whatever cannot move with polythene inside the garage and put a bucket under the worst of it. Where rain is getting straight in, a temporary cover can be strapped or weighted from outside by someone trained to handle asbestos cement, without drilling through anything. Making a leaking roof safe comes before the full survey, so mention the leak when you call.
Cold, wet weather raises the stakes, and our page on replacing a garage roof in winter looks at what the season changes.
From survey to written quote
We start with pictures of the break, the neighbouring sheets, the fixings, the purlins and the underside from inside the garage. They show whether the damage is local or spread along the run, whether the timbers have got wet, and whether the remaining sheets will hold if left alone.
You then get one written total. Three things move it more than any others: how much of the roof has broken, how much asbestos waste has to be bagged and taken to a site that accepts it, and how easily a vehicle and a skip can reach the garage. Our habit is to propose nothing beyond what the fault needs. One broken sheet on an otherwise sound roof can mean replacing just the affected sheets. A roof past saving means taking it all down and re-covering it, and we explain which applies and why.
Our written guarantee on the workmanship lasts a decade, the plot is swept and every offcut and fragment is carted off.
Typical costs and further reading
National figures show the scale and are not a price for your garage. MyBuilder's asbestos removal guide, updated in August 2026, puts removal of a single garage roof at around £350 to £1,295 and a double garage at £650 to £1,800, with whole-garage removal running £1,100 to £3,750. Checkatrade's roof replacement guide suggests budgeting £950 to £3,750 for removal and disposal. Notifiable work, awkward access or a collapsed roof pushes towards the top.
Check whether any quote includes VAT, carriage of the waste and a replacement covering, because a figure for taking sheets off alone leaves an open frame. Our guide to shed roof felt and coverings shows what lighter outbuildings are re-covered with, and garage roofs and home insurance is worth reading before you assume a policy will pay. For timescales, see how long a garage roof replacement takes. The main hub is garage roof replacement in Swindon.
Photographs of the break plus the garage size are enough to begin. Ring 01793 626096, send a WhatsApp message or fill in the form.