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Five reasons to map asbestos roofs

The Dutch National government has decided upon a national ban on asbestos roofs. All asbestos containing roof material should be removed by the end of 2024.* This is of course easier said than done. And to develop efficient policies it is crucial to have data. Especially for the Dutch municiaplities, as they are responsible to maintain the ban.

Readar has now identified asbestos roofs for more than 140 Dutch municipalities. We often get the question: ‘Why should we map asbestos roofs?’. Also, people are often curious about what other municipalities did with their data. In this blogpost we discuss the 5 most common applications of asbestos roof data.

1. What is the current status of asbestos roofs?

The primary reason to map absestos roofs, is that a municipality wants to know their current status. How big is the problem of asbestos roofs in our municipality? Often, these questions are posed by the city council. The four main questions are:

  • How many buildings in our town have an asbestos roof?
  • How many square metres of asbestos roofing is there?
  • Where is it?
  • Which type of buildings/owners have asbestos roofs?

An inventory of asbestos roofs from aerial imagery can answer all these questions.

2. Inform owners about the ban

Once data is available, a municipality can inform the owners. We often hear two reasons to do this:

  • Duty of assistance towards owners. Homeowners are responsible for their own property. But municipalities feel a responsibility to inform them nonetheless. In some cases, this responsibility is used to build a dossier about the owner for legal purposes. If municipalities wish to enforce the ban by 2025, their legal foundation would not be solid without informing the owner ahead of time.
  • Prevention of illegal sanitation. The theory behind this approach is that if the owner of an asbestos roof knows that the municipality knows about it, he/she will be less likely to illegally sanitize the roof. We state this carefully, as we don’t know whether this is true. The local policy regarding garbage drop off (whether this can be done free of charge for asbestos) is a factor as well.

Before a letter can be sent, an address is needed. Many buildings do not have an address, think of sheds on a plot of farmland, or carports. Readar has developed a method to assign addresses to these type of buildings.

PS: As mapping from aerial imagery is not the same as laboratory testing we are talking about ‘asbestos suspicious’ roofs. It is important to make this clear in correspondence. This avoids frightening people for no reason.

3. Determining the approach and policy

A number of municipalities go beyond merely informing the owner. They want to perform a more active role. For example, by providing technical, fiscal and subsidy advice to owners of large asbestos roofs through personal communication.

The data on square meters and target groups form the input for an effective plan of approach. A common situation is that a small group of owners own more than 50% of the total asbestos roof surface. In this case it is often more productive, and therefore recommended, to personally approach each owner. Other methods exists besides a personal approach, namely:

  • Asbestos train region ‘Achterhoek’.
  • Asbestos loan municipality of Lelystad.
  • Process support on an owner or neighborhood level.

For a complete overview we refer to:

4. Determining budget

Stimulating owners to sanitize their roofs is formally not a part of the responsibilities of municipalities. However, some municipalities still choose to take a more active role in the sanitation of asbestos roofs. Before any decision can be made concerning these kind of measures, it is good to know what the necessary budget is for these measures. A personal meeting with an owner costs money. It is therefore good to know if 50 or 500 of those meetings are needed.

5. Monitoring progress

After municipalities know the current status the following question is often: “Are we on track for 2024?”. This question can be answered with the following formula:

current year + (total surface to be sanitized / sanitized surface per year) = planned end date.

Using the data from the asbestos roof map we know the total surface to be sanitized. The sanitized surface per year can be determined by comparing aerial photographs of different years to identify which roofs were removed.

More information on mapping asbestos roofs?

Are you interested in an asbestos roof mapping? Or in the monitoring of asbestos roofs? Please contact us at:

* The national ban is no longer official. However, many municipalities aim for an asbestos free environment. Therefor this data is still very valuable.