The short answer
If your garage has corrugated cement sheets and they are in sound condition, the usual advice is to leave them alone, keep them clean of moss only by gentle means and never break, drill or scrub them. Under HSE rules a gentle, whole-sheet removal sits in the non-licensed category, though the waste needs hazardous handling and cannot be treated as household rubbish.
Recognising an asbestos cement roof
Asbestos cement was widely used for garage and outbuilding roofs, most often as large corrugated sheets, grey and often streaked with moss or lichen. The HSE advises assuming asbestos is there when a building dates from before 2000, whether new-built or refurbished then. A garage of that age with corrugated sheets stays under suspicion until a laboratory result says otherwise.
You cannot identify asbestos by looking. Newer fibre-cement and metal sheets look much the same, and the HSE accepts that asbestos items are hard to tell from their non-asbestos equivalents by eye. Only a sample taken by a competent person and analysed in a laboratory gives an answer, and that is the sound basis for any decision.
The danger comes from fibres released when the material is damaged, not from the roof sitting there. Sheets in good condition that are left alone shed fibres at a level that gives no cause for concern. Breaking, drilling, sawing and scrubbing are what release them.
A garage roof also deserves care because it is fragile. In the HSE's guidance, asbestos cement roofing is always fragile, so a person's weight can take it through. Falls through fragile roofs are a major cause of death and injury, so nobody should walk on one.
Leaving it, or having it replaced
A roof that is intact, with no cracks, crumbling edges or large holes, can usually be left in place and watched. Moss on the surface is a cosmetic matter, and it should not be scraped or pressure washed because that damages the surface and spreads fibres. If cleaning is wanted, take specialist advice.
Replacement becomes sensible when sheets are cracked, broken, badly weathered or leaking, when you want to alter the garage, or when the roof is being replaced as part of a larger project. A leaking asbestos roof is often cheaper to deal with by replacement than by repeated patching, since patching means working on the material.
MyJobQuote gives a typical UK cost for removing an asbestos roof of around £2,750, an asbestos survey at around £325, and garage roof replacement in general between £750 and £3,500 (MyJobQuote, Sep and Oct 2026). Your own figure depends on the size, the access, the condition of the sheets and how the waste is handled.
Cover is also an option in some cases, where a new roof is fitted over the old without disturbing it. Whether that suits your garage depends on its structure and condition, and a surveyor or roofer can advise.
Our page on flat roofing covers the replacement coverings that suit a garage.
How the rules treat removal
The HSE separates asbestos work into licensed, notifiable non-licensed and non-licensed. For asbestos cement such as roof sheeting, the HSE puts careful handling, with no breaking up of the sheets, in the non-licensed category, and weathered cement that is otherwise undamaged counts too.
Once sheets are going to be smashed or broken up, the HSE moves the job into the notifiable non-licensed category. That brings a notification to the enforcing authority and a register of work, with health records kept for 40 years.
A different material is asbestos insulating board, found in places such as external soffits. Work on it that will run beyond a short duration is licensable, which means a specialist contractor holding the right authorisation from the HSE. A garage roof with boarded soffits or panels needs the soffits checked separately.
Where a roof is suspected to contain asbestos, we recommend a sample is tested first, and removal should be carried out by a contractor working to the HSE's rules for that category of work.
The person doing the removal must plan the job, protect themselves and others, and avoid breaking the sheets. Owners should not attempt removal themselves, because the risk is to health and the rules are strict.
Waste, and what we do
Asbestos waste travels as hazardous waste, never with ordinary rubble and never in a household bin. The government's hazardous waste guidance exempts domestic hazardous waste other than asbestos waste, so even a homeowner gets no special allowance. It must be double-wrapped and labelled, as HSE guidance EM9 sets out, and taken by a carrier registered to move hazardous waste.
Ask any contractor how the waste will be wrapped, labelled and carried, and to see the consignment note afterwards. A firm that says the sheets will be thrown in with general rubble is not following the rules.
When we survey a garage, we look at the roof, note the type of sheeting and its condition, and tell you whether we suspect asbestos cement. If so, we explain the options and recommend testing before any work begins. We photograph the roof and the structure, and the replacement is quoted as one written total.
We aim to leave a sound roof alone, and recommend replacement only when the evidence shows it is needed. Our flat roofing hub covers the new coverings, and planning permission for a flat roof covers the planning side of a new garage roof.
