Identifying Asbestos on Your Roof

How to Identify Asbestos on a Roof

The most reliable visual clues: large corrugated sheets (often 1.25 m × 1.10 m), light grey to dark grey, with a slightly fibrous surface visible to the naked eye. These sheets, sold under the Eternit brand between the 1950s and 1997, are recognisable by their uniform appearance and relative lightness. Over time, they become friable, turn green from algae, and develop micro-cracks on the surface.

Artificial fibre-cement slates are harder to distinguish from natural slate. Clues: very regular thickness (unlike natural slate which varies), perfectly smooth surface, uniform dark grey colour, lighter weight. In case of doubt, only a sample taken for laboratory analysis can confirm the presence of asbestos.

The building's age is a crucial indicator. If your house was built or renovated between 1950 and 1997, the probability of asbestos in the covering is significant. Buildings from before 1950 used little fibre-cement. Buildings after 1997 should theoretically contain none, as the ban came into force on 1 January 1997.

If you are selling your house and it dates from before 1997, an asbestos survey is mandatory. It must be carried out by a certified professional who will inspect the roof and, if needed, take a sample for laboratory analysis.

Asbestos in Good Condition vs Degraded Asbestos

It is essential to understand that asbestos does not present the same level of danger depending on its condition. Asbestos-cement in good condition, uncracked and undisturbed, releases very few fibres into the air. It can remain in place under regular monitoring without immediate risk to occupants. This is called 'retention with monitoring'.

However, degraded asbestos-cement — cracked, crumbling, broken, or covered in moss penetrating the material — releases fibres continuously. Weather, frost, and plant growth accelerate this degradation. If your fibre-cement roof dates from the 1960s-70s and has never been maintained, it is probably in a condition that justifies at minimum a thorough diagnosis.

Regulations provide three action levels depending on material condition: level 1 (good condition) = periodic check every 3 years; level 2 (intermediate condition) = airborne fibre measurements and corrective action if thresholds exceeded; level 3 (poor condition) = mandatory removal or encapsulation works within 3 years.

What to Do If You Suspect Asbestos

The golden rule: do not touch anything. Never break, drill, sand, cut, or high-pressure wash a material suspected of containing asbestos. Even a simple drill hole to fix an aerial bracket can release thousands of dangerous fibres. If a sheet is broken, do not move it: tarp it or wet it to trap fibres, and call a professional.

Have a diagnosis carried out by a certified professional. The surveyor will take a small material sample and send it to an accredited laboratory for analysis (results within 5 to 10 working days). The cost of an asbestos survey specific to the roof is €100 to €300 depending on area and complexity — a trivial investment compared to the health risks.

If asbestos is confirmed and in good condition: regular monitoring (visual inspection every 3 years) is generally sufficient. Document the initial condition with photos and store the survey report in a safe place. If you plan any work on the roof (even minor), always inform the roofer of the asbestos presence.

If the asbestos is damaged or you want to renovate your roof: removal must be done by a company specifically certified for this type of work. A removal plan is drafted and approved by authorities at least 30 days before the start of works. This is mandatory — doing otherwise is illegal and dangerous.

Asbestos Removal: Process and Costs

Removing an asbestos roof is a strictly regulated process. The site is protected (tarpaulins, barriers), workers wear special equipment (overalls, masks), and air quality is continuously monitored during the work.

Sheets are carefully removed without breaking them, then sealed in airtight bags and sent to an approved treatment centre. You receive an official waste tracking document — keep it carefully, as it will be required if you sell the property.

The overall cost of asbestos roof removal ranges from €30 to €60/m² for sheet removal, plus €15 to €30/m² for transport and disposal at an approved facility. For a 100 m² roof, expect between €4,500 and €9,000 all-inclusive (excluding the new roof covering). Work duration varies from 2 to 5 days depending on area and access complexity.

At Toit des Dômes, we work in partnership with certified asbestos removal companies in Puy-de-Dôme. We coordinate the entire project: initial diagnosis, removal by our partner, and immediate installation of your new covering by our team. You have a single point of contact for the entire duration of the project. Contact us for a free estimate.

Financial Assistance and Alternatives to Removal

The extra cost of asbestos removal can be partially offset by grants: ANAH (National Housing Agency) offers subsidies for low-income homeowners as part of housing renovation. Some local councils and inter-communal bodies offer supplementary grants. Enquire with ADIL (Departmental Housing Information Agency) in Puy-de-Dôme.

The alternative to removal is encapsulation: a watertight coating is applied over the asbestos-cement sheets to prevent fibre release. This solution is less costly than removal but is only suitable for materials in reasonable condition with sufficient remaining lifespan. It is subject to the same regulatory requirements as removal (certified company, works plan).