The short answer
Not always, but you do when the roof may contain asbestos. A modern tiled or slated house roof usually does not need one. A garage, outbuilding or older building with corrugated cement sheets, or any job that will disturb unknown materials such as boards, soffits or old insulation, needs the material identified before work starts. If there is doubt, a sample is tested first and nothing is broken up until the result is known.
Where asbestos turns up on a roof
Asbestos cement was widely used for corrugated roof sheets, for flat or profiled panels on garages and sheds, and for rainwater goods, flues and some fascias. You are most likely to meet it on a detached garage, a farm or industrial building, a lean-to or an older extension. It can look like a pale grey cement sheet, often weathered and mossy, with a ribbed or wavy profile.
Ordinary clay and concrete tiles, natural slate and most lead flashings are not asbestos. The risk lies with the sheets, with boards under eaves and with textured or insulating panels inside the roof space. Appearance is not enough to be sure, because other fibre-cement products look much the same.
If your property has a garage or outbuilding with grey sheet roofing and you are planning any work, assume it is suspect until it has been checked. That is the safe default, and it costs very little to confirm.
Roof spaces can hold other suspect materials. Sprayed coatings, lagging on old pipework, loose-fill insulation and boards fixed under the eaves were all used in different periods, and some contained asbestos. None of them is a reason for alarm, but each is a reason to test before cutting or pulling anything out.
What the rules ask for
The Health and Safety Executive treats the careful removal of asbestos cement sheets, handled whole and without breaking them, as non-licensed work. It still needs a risk assessment, proper controls and trained workers. If the material is going to be substantially broken up, for example by dropping the sheets, it becomes notifiable non-licensed work, with extra duties. The HSE page on non-licensed asbestos work sets out the categories.
For small structures such as garages, the HSE guidance also points to overlaying as an alternative to removal, as long as no other asbestos material, such as insulating board, is present. Our own approach is simple: we do not break up sheets, we say what we find, and we stop if something unexpected turns up.
The point of the rules is to keep fibres from being released, and the danger comes from breathing in fibres released by breaking or abrading the material. Sheets left whole and undisturbed are far less of a concern than sheets that have been snapped, drilled, brushed or washed down with a jet.
When a survey or a sample test makes sense
If you are not sure what the roof is made of, the sensible step is to have a small sample taken and analysed by a laboratory. That takes the guesswork out, and it is quick. A survey is a wider exercise, in which a surveyor looks over the building and samples every suspect material, and it is more usual before a refurbishment, a demolition or work on a larger or commercial building.
For a standard re-roof of a modern house with tiles, a survey is rarely needed. For work that involves boarding, loft insulation of unknown type or a garage roof of unknown sheet, it is wise. We take a view at our own survey, and if we suspect anything we say so before we quote, rather than finding out halfway through the job.
If a garage roof is in poor condition but is not being touched, there is no duty to do anything urgent. It becomes a question when work is planned nearby, such as a new fascia, a gutter swap or a neighbouring extension that needs the sheets moved.
What to expect from a roofer
A responsible contractor will ask what the roof is made of, look closely at any sheet material and explain what they plan to do. They will not drop, snap or drill into suspect sheets, and they will not sweep or pressure wash a roof of unknown material. They should be able to tell you what the plan is for waste, since asbestos cement must go to a suitable facility, not a normal skip.
Our free survey includes photographs of your roof and a note of anything we think needs testing. If testing is needed, we explain the route and the likely effect on the schedule. Other points about how we survey are set out on the roof inspections in Basingstoke.
If a test confirms asbestos, you have choices. The sheets can be removed whole by trained workers, or in some cases overlaid with a new covering if the structure allows it. We explain the options and the likely cost range before you commit, and we do not go ahead without your agreement.
Every roof is different. A free survey with photos settles it for yours.
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