The easiest way to understand a safe removal is to see what it avoids. Asbestos cement gives off dust when it is smashed, drilled, sanded, scrubbed or dropped. A removal that keeps every sheet whole therefore gives the dust nowhere to come from. Almost everything in the method, from the order of the work to the tools left in the van, comes from that single idea.
Here is the sequence we follow on a garage with corrugated cement sheets: survey and sampling, setting up the site, unfixing and lowering the sheets, wrapping, cleaning up, and the replacement roof. HSE guidance supports this approach for intact material, and our guide to the HSE rules for asbestos garage roofs explains the categories. For the wider service, see garage roof replacement.
Stage one: the survey, the sample and the plan
Nothing is touched until we know what the roof is made of. A visual check can suggest cement sheet, but a laboratory result is the reliable answer, and an owner who has not yet had a test should arrange one first. MyBuilder's 2026 asbestos removal guide lists a basic survey at around £50 and a fuller one at £200 to £245, and our answer on asbestos test costs covers what is involved.
What the survey records
We circle the building, then stand under the roof inside the garage to see the sheets from beneath. The points we write down are the sheets themselves (whole, cracked, weathered or broken), what fixes them to the purlins, the condition of the timber or steel underneath, any skylight sheets or fittings, the gutter arrangement, and where the sheets can be lowered and stacked. We photograph each slope so the condition is on record before anything is moved.
Choosing the method
The plan states how each sheet will be unfixed, how it will be lowered, where the stack will stand, and which route the waste takes to the vehicle. It also records whether the roof is likely to remain in the HSE group for non-licensed work or move into the notifiable group. If the sheets are already in pieces, the plan changes and the notification step is added before the start. The call is made when we survey, and never up on the roof.
Stage two: setting up the site
Before the first bolt is touched, the ground and the area around the garage are prepared. Pets and children are kept away, windows of neighbouring buildings that face the garage are noted, and any washing or play items are moved. A clear working area is marked off, with a route in and out that avoids walking through the stack.
Ground protection
Heavy polythene sheeting is laid where sheets will be lowered and stacked. If a sheet does crack on its way down, the debris lands on a surface that can be wrapped up and carried away, instead of lying in the garden soil. Gutters that carry asbestos cement fall into the same plan: they are lifted, not snapped, and any gutter debris is bagged.
People and equipment
Workers wear disposable coveralls and suitable respiratory protection, and the equipment list is simple: spanners and bolt cutters for unfixing, wrapping materials, labelled bags, and a vacuum designed for asbestos dust. Notable by their absence are power saws, angle grinders and drills, because every one of those would create dust from a material we aim to keep whole.
Working at height
Asbestos cement sheets are brittle with age and cannot take a person's weight. Falls through fragile roofs are a recognised hazard on garage and outbuilding roofs, and the working platform is planned accordingly, with the load spread by crawling boards on the supporting members, and edge protection or a tower where the height requires it. Nobody walks on the sheets.
Stage three: unfixing and lowering the sheets
Corrugated cement sheets are held on the purlins by hook bolts or screws through the crowns of the corrugations, and neighbouring sheets overlap along their edges. Each fixing is released, not broken. A bolt that has seized from age is cut and not hammered, and a stuck sheet is eased free by hand, never levered hard.
Working from the ridge down
Sheets generally come off in the reverse order of laying, beginning at the highest point and working towards the eaves, with the ridge pieces first. This keeps the crew standing on the supporting frame beneath the sheets they have not yet touched, and means a lifted sheet is never lying above one still waiting to go. Overlaps are separated along their line, not forced apart.
Lowering, never dropping
Each sheet is lifted clear and lowered, either by hand down a ladder or by rope and sling to the ground. HSE's example of work that tips into the notifiable group is dropping an asbestos cement roof, and dropping is exactly what the method avoids. The sheets are laid flat on the polythene, stacked in a pile of manageable height, and each one checked as it goes down. Any sheet that cracks in handling is set apart and wrapped on its own.
Sound sheets come down one at a time and are never thrown. Speed is not the aim. Controlled, even handling is.
When a sheet cracks anyway
Old sheets can be brittle at the fixing holes, so now and then one cracks as it is released, however carefully it is handled. The response is calm and immediate: the sheet stops moving, the pieces are gathered onto the polythene, and the cracked sheet is wrapped separately. The crew then looks again at the sheets still on the roof, and if the damage is spreading rather than isolated, the plan is revisited before work continues. A single crack is a handling issue, whereas several broken sheets suggest the method needs to change.
Fittings, gutters and the rest
Ridge pieces, barge boards of cement sheet, and cement gutters or downpipes come off by the same rules. Fixings are collected as they are released so that nothing is left on the roof or underfoot.
Stage four: wrapping, labelling and loading
Once sheets are on the ground, they are wrapped as a stack. The standard method is heavy-duty polythene wrapped round the pile and taped, then marked as asbestos waste so that anyone handling the load later knows what it is. Offcuts, debris and the used polythene go into the same labelled containment.
Why wrapping matters
Wrapping keeps any loose surface dust and any fragments inside the load while it is moved. It also keeps rain off the sheets, which matters because a wet stack is heavier and harder to handle. The labelling protects the people further along the chain, from the vehicle driver to the site that receives the load.
Loading the vehicle
The wrapped stack goes onto a suitable vehicle on the polythene-lined route, loaded flat and secured. Waste is never put into an ordinary skip, and the aim is to avoid leaving it on the drive overnight. What happens to the load from there, including the paperwork that follows it, is covered in our answer on asbestos roof sheeting disposal, which takes up the story where this guide stops.
Cost of this stage
Wrapping, labelling, transport and the receiving site's charge are part of the job, because they scale with the number of sheets and not with the size of the replacement roof. For the national ranges of removal, see the removal bands in our garage roof cost guide.
Stage five: cleaning up and checking the ground
After the last sheet has gone, the garage frame, the floor of the building and the working area are cleaned. Dry sweeping is avoided, because it lifts dust, so the cleaning uses damp wipes and an asbestos-rated vacuum. Used wipes, the polythene underlay and the coveralls from the day go into the labelled waste.
Walk-through
A final walk-through looks at the ground under the eaves, the gutters line, the roof space beneath where the sheets were and the driveway, with photographs. If a sheet has broken during the job, the area is checked again and the clean-up repeated before anyone steps back in.
Contents of the garage
Cars, tools and stored boxes are best moved out before the work, or covered with sheeting if that is not possible. We agree this at the survey, and note anything that cannot be moved. Items that were uncovered during the removal are not the same as items that were left in a clean-up area, which is why the sheeting step is recorded in the plan.
What you get from us
You receive photographs of the finished clearance and the written record of what was removed, which is useful if you later sell the property or are asked what became of the old roof. Waste leaves with us, the ground is left clear, and the 10-year workmanship guarantee in writing applies to the new roof.
Stage six: building the replacement roof
Removing the old sheets gives the first proper view of the structure underneath. Purlins, rafters and fixings are checked for rot, rust and movement, and any repair is agreed with you and added to the written quote before it is carried out.
Pitched sheet, tile or flat
The choices for the new roof are broad. A like-for-like sheet roof in a modern material, a metal profile with an anti-condensation backing, a tiled pitched roof, or a flat roof with a fresh deck all remain open. The materials are compared in our pitched garage roofs guide, and the metal option is covered in the box-profile sheet guide. Each has its own weight, pitch and fixing, so the new covering may need a different support from the old one.
Weight and approval
A modern sheet is far lighter than cement, so the load on the frame usually falls. A tiled roof is heavier, and a covering 15 per cent or more heavier needs a structural check and Building Regulations approval, according to the Planning Portal. Where approval applies, we explain it and file the notification. For a garage that is heated or attached, building control can also tell you whether Part L applies.
Closing the job
The new roof goes on once the frame is sound, the debris is gone and the trims are fitted. The result is a roof with the same footprint and a new life, set out in a written quote covering removal and replacement.