Asbestos cement roofs : take extra care !

📖⌚ 8 minutes.  📅💫 .

Many garage lots from the 60s and 70s are currently up for sale. Ageing owners prefer to sell their garages rather than continue to devote time to rental management. All these old buildings have asbestos cement roofs, which may contain asbestos. Be very careful when buying to avoid losing a lot of money !

Roof with fibre cement panels

History of asbestos use

Asbestos was widely used in the late 19th and early 20th centuries. It is an inexpensive and versatile material with insulating properties and good fire resistance. The construction and public works industries used it en masse, mixing it with concrete to create fibre cement or cement asbestos sheets.

The use of asbestos was restricted from the 1970s, following an increase in lung disease. The use of asbestos has been banned in France since 1997, and in Europe by a European directive in 2005.

Asbestos in fibre cement panels

Asbestos cement sheets may contain asbestos. Any building constructed in the 1990s that has the visual characteristics of this type of roof (corrugated cement sheeting) will contain asbestos. Gutters, cornices and ridge caps may also contain asbestos.

Asbestos cement roofs are old and have been exposed to the elements for many years. If they haven’t already, they risk deteriorating rapidly while releasing asbestos fibres and particles into the air.

Risks associated with asbestos

When faced with a positive asbestos diagnosis, it is important not to panic, but to be aware of the risks. The owner of a garage may be held liable if asbestos fibres are released. Some roofing sheets contain up to 15% asbestos. A damaged fibre cement roof is dangerous. Exposure to the elements, such as the sun, rain and cold, will damage your roof over time.

Asbestos is dangerous to humans when inhaled. Particles that enter the respiratory tract increase the risk of lung cancer and other respiratory diseases. Asbestos-related diseases are the leading cause of work-related deaths (excluding accidents at work) and the second leading cause of occupational diseases.

Buying a garage with an asbestos cement roof

Since 2005, all owners selling property that may contain asbestos have been required to have an asbestos technical file (DTA) drawn up by a professional. Unfortunately, this French regulation, standard NF EN 494, is not always followed by sellers of car parks or garages with fibre cement roofs. If the roof of a garage contains asbestos and the buyer has not received a DTA certificate, the buyer may file a legal claim for latent defect…

The owner of a dwelling must inspect asbestos-contaminated elements every 3 years and carry out repair work within 6 months of noticing any deterioration. As you can see, the owner of a garage is under no obligation to do so, but before you invest in a garage, it’s essential that you ask the seller for a DTA file if :

  • the roof is made of fibre cement or asbestos cement sheets.
  • the wall elements are bitumen shingles.

Should asbestos cement sheets be removed or contained

The most important thing is not to rub, break, pierce or scrape the asbestos cement sheets. High-pressure cleaning is not recommended to avoid releasing asbestos particles. Remove the sheets and start again with a new, trouble-free roof. There is a health risk in treating this type of material yourself.

We advise you to call in professionals to help you remove the sheets. Ecological standards require the use of overalls, gloves and masks to pack the pieces of asbestos cement in plastic bags. Don’t forget that most waste collection centres no longer take asbestos cement sheets, so it will be very difficult to get rid of them… Of course, the last thing you want to do is turn them into rubble.


The other, less costly solution is to contain the asbestos inside an additional structure. Containment of the fibre cement roof insulates the sheets from the ambient air ; in most cases, elastomeric bitumen is used.

When should action be taken on asbestos-covered fibre cement boards

The European Union has banned the use of asbestos since 2005. The problem is the wear and tear of asbestos cement sheets over time, and the risk of spreading asbestos particles. At some point, every owner of this type of garage will have to take preventive action against asbestos cement. The decision to carry out work on an asbestos cement roof can come from several quarters : a responsible owner, a neighbour who feels exposed to the danger, the town hall or the prefecture.

Before buying a property, you can also contact your local council to find out what their policy is on fibre cement roofs. If you own a garage with an asbestos cement sheet roof, you have two options :

  • Asbestos removal, with total replacement of the roof.
  • Asbestos containment.

All homeowners are required to carry out regular checks on their fibre cement roofs to see how they have aged over the years. If a fibre cement sheet is damaged, broken or crumbling, there is a risk of asbestos particles spreading into the air. The owner is obliged to take steps to resolve this problem and protect the safety of people in the vicinity of asbestos-containing roofing.

Confining asbestos fibre cement sheets

This remains the most economical solution, even if it does not completely solve the problem. Containing a fibre cement roof does not remove the asbestos present in your building. Containment involves trapping or sandwiching the fibre cement sheets between another material.

Asbestos-cement sheets are also encapsulated to limit exposure to the elements and the risk of asbestos fibres and particles spreading into the air. Professionals carrying out this work must be qualified and wear special equipment (overalls, gloves, breathing mask).

The principle is to apply a special product to the entirety of the fibre cement panels before encapsulating it with corrugated galvanised sheets (for example) positioned above and below the panels. In this case, the asbestos remains inside your roof, so you’ll need to check the integrity of the encapsulating materials regularly.

Asbestos removal and roof replacement

This is the best solution for dealing effectively with a roof containing asbestos. Replacing the roof is an expensive but long-lasting operation that definitively solves the risk associated with the presence of asbestos in a batch of garages or a building. A professional intervenes to protect his teams and the neighbourhood. They will dismantle the fibre cement sheets and place them in a suitable container. The company manages the removal and disposal of special waste containing asbestos particles and fibres.

Once the old roof has been removed, any risk of asbestos spreading is a thing of the past. Then it’s time to rebuild the roof, using a range of solutions and materials that pose no risk to your health or that of your neighbours. This last stage is the simplest part of the work, and includes all the stages involved in new construction.

Estimating the cost of the work 🔐

It’s very difficult to estimate the cost of re-roofing a garage or a group of garages. The condition of the panels, accessibility and the surface area to be treated are all factors that have an impact on the price. Dismantling and disposing of the panels represents the biggest item of expenditure on the repair work. Like any wise buyer, our investor members have already obtained quotes from specialist companies. These are used to assess the cost of asbestos removal and disposal, so that we can best calculate the value of a property for sale. Below is a detailed example of an estimate for repairing a fibre cement roof.

You must be a member of the club to see the cost estimate for a fibre cement roof containing asbestos.


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