Different types of asbestos and where are they found?

Types of asbestos: what you need to know before renovating your home

When renovating an older property, you may encounter materials containing asbestos. Asbestos was once widely used in roofs, facades, pipes, flooring and technical installations. The material was strong, fire-resistant, moisture-resistant and insulating, but it can pose serious health risks when asbestos fibres are released and inhaled.

Fibres can become airborne when asbestos-containing materials are broken, cut, drilled, sanded or removed. Before beginning roofing or facade work, it is therefore important to determine whether asbestos may be present. Early identification helps prevent health risks, delays and unexpected costs during the renovation.

Why was asbestos used so extensively in the past?

Asbestos is a collective term for a group of naturally occurring minerals made up of extremely fine fibres. Because of its useful technical properties, it was incorporated into thousands of construction products over several decades.

Asbestos was:

• resistant to high temperatures;
• fire-resistant;
• moisture-resistant;
• resistant to wear;
• resistant to chemicals;
• electrically and thermally insulating.

The production of asbestos-containing materials was banned in Belgium in 1998. As existing stocks continued to be used for some time, 2001 is treated as an important reference year in Flanders. Buildings constructed before 2001 may therefore still contain asbestos-containing materials. 

Why is asbestos dangerous?

Asbestos primarily becomes a risk when microscopic fibres are released and inhaled. These fibres can penetrate deep into the lungs and remain there for a very long time.

Exposure to asbestos can cause serious diseases. The level of risk depends on factors including:

• the condition of the material;
• how firmly the fibres are bound within it;
• the quantity of fibres released;
• the duration and frequency of exposure;
• the way the material is handled or removed.

An intact asbestos-containing material generally presents less risk than material that is damaged, weathered or friable. However, even firmly bound asbestos can release fibres over time as a result of wear and exposure to the weather. 

What types of asbestos are there?

There are officially six different types of asbestos. The three varieties most commonly found in Belgian buildings are chrysotile, crocidolite and amosite.

Colour-based names can help describe the different varieties, but you cannot reliably identify the type of asbestos present solely from its colour or appearance.

White asbestos – chrysotile

Chrysotile, also known as white asbestos, was the most widely used type. Its relatively flexible fibres were incorporated into a wide variety of construction materials.

Chrysotile may be present in:

• corrugated sheets;
• roof and facade slates;
• flat asbestos-cement boards;
• facade cladding;
• vinyl tiles and flooring;
• seals and gaskets;
• certain plasters, adhesives and cement products.

Although chrysotile is sometimes described as less dangerous than other types of asbestos, any exposure to released asbestos fibres poses a health risk. White asbestos should therefore never be regarded as safe.

Blue asbestos – crocidolite

Crocidolite, also known as blue asbestos, consists of very fine, straight fibres. It was mainly used in products that needed to withstand heat, fire or chemicals.

It may be present in:

• pipe insulation;
• fire-resistant boards;
• insulation around heating systems;
• sprayed asbestos;
• industrial installations;
• certain older cement products.

Blue asbestos is considered particularly hazardous, especially when the material is loosely bound, damaged or weathered.

Brown asbestos – amosite

Amosite, also known as brown asbestos, was primarily used for thermal insulation and fire protection.

It may be present in:

• ceiling and insulation boards;
• partition walls;
• pipe insulation;
• technical rooms;
• heating installations;
• fire-resistant coverings.

Brown asbestos also contains fibres that can penetrate deep into the lungs. Materials containing amosite must therefore be handled with particular care.

Where can asbestos be found in a home?

Asbestos is not found only in corrugated sheets or old slates. It was incorporated into a large number of products and may be either visible or hidden.

Possible locations include:

• roof slates and corrugated sheets;
• flat roofing and facade boards;
• roofing underlay boards;
• chimney flues;
• rainwater drainage systems;
• pipe insulation;
• heating installations;
• ventilation ducts;
• ceiling and wall boards;
• flooring and tile adhesives;
• window sills;
• thresholds;
• older plaster and cement layers;
• mastics, sealants and gaskets;
• technical installations.

Render, plasterwork and other finishing layers applied before 2001 may also be considered suspect in some cases. Asbestos can also be concealed behind walls, beneath flooring or under layers added during later renovations. 

Bonded and non-bonded asbestos

In addition to the asbestos type, the way the fibres are held within the material is particularly important.

Bonded asbestos

In bonded asbestos products, the fibres are firmly fixed within a binding material such as cement, plastic or bitumen.

Examples include:

• asbestos-cement corrugated sheets;
• roof and facade slates;
• flat facade panels;
• certain window sills;
• cement pipes.

When these materials remain intact and in good condition, fibres are generally less likely to be released. During renovation work, however, the materials can break, crack or become damaged. Ageing and weathering can also weaken the binding material.

Non-bonded asbestos

In non-bonded asbestos products, the fibres are loose or only weakly bound. They can therefore become airborne much more easily.

Examples include:

• sprayed asbestos;
• soft pipe insulation;
• older fire-resistant insulation;
• loose insulation around heating installations;
• certain insulation and ceiling boards.

Non-bonded asbestos generally presents a greater risk and requires a specialised approach. Private individuals may not dismantle this type of material or take it to an ordinary recycling centre. 

Can you identify asbestos yourself?

Asbestos often cannot be identified with certainty from the colour, shape, age or structure of a material. A board may look like an ordinary cement product while still containing asbestos. Conversely, not every old material automatically contains asbestos.

Certain characteristics may make a material suspect, but only a professional assessment and, where necessary, analysis by an accredited laboratory can provide a reliable answer. OVAM states that laboratory analysis is often the only way to determine with certainty whether a material contains asbestos. 

Never take a sample yourself without the proper preparation or guidance. Incorrect sampling can release and spread fibres. Have sampling carried out or supervised by a qualified asbestos expert, or seek advice from an accredited asbestos laboratory beforehand.

Is an asbestos certificate mandatory before renovation?

An asbestos certificate is not automatically required for every private renovation. However, OVAM strongly recommends obtaining one before renovating a building constructed before 2001.

Since 23 November 2022, an asbestos certificate has been mandatory when selling an accessible construction dating from before 2001. By 2032, every owner of such a building must have a valid asbestos certificate. For the communal areas of certain apartment buildings, the obligation applies by the end of 2026 at the latest. 

A standard asbestos certificate is based mainly on a non-destructive inspection. Hidden materials behind floors, walls or roof structures may therefore not always be identified. For major renovation or demolition work, an additional destructive survey may be required in the areas where the work will take place. 

What should you do if you suspect asbestos?

When you suspect that a material contains asbestos, stop the work and avoid any action that could create dust or cause the material to break.

Follow these precautions:

• touch the material as little as possible;
• never drill, cut, grind or sand it;
• do not break it or throw it down from a height;
• do not clean it with a pressure washer;
• do not sweep or vacuum suspected asbestos dust using ordinary equipment;
• have the material professionally assessed;
• arrange any necessary removal before the other renovation work begins.

Several hazardous ways of handling asbestos are prohibited in Flanders. As a general rule, suspected material must be treated as asbestos-containing until a valid analysis proves otherwise. 

Who is permitted to remove asbestos?

Not all asbestos-containing materials are removed in the same way. Who is permitted to carry out the work depends on factors including:

• the type of material;
• its condition;
• its location;
• the likelihood of fibres being released;
• the removal technique required.

Certain intact, bonded asbestos products may be removed under strict conditions using the simple-handling method. Other materials, including damaged or non-bonded asbestos, require a company authorised to perform specialised asbestos removal. 

Before work begins, have the legally and technically required method determined. Do not assume that every contractor is authorised to remove asbestos.

Asbestos in roofs and facades

Asbestos-cement products are regularly encountered during roof and facade renovations, including:

• corrugated sheets;
• artificial slates;
• flat facade panels;
• roofing underlay boards;
• roof-edge components;
• chimney and drainage components.

These materials can deteriorate through age, moss growth, frost damage and exposure to the weather. Cleaning an asbestos-containing roof or facade with a pressure washer is prohibited because it can release fibres.

When asbestos-containing roofing or facade materials are removed, the subsequent renovation work must also be carefully coordinated. Asbestos-containing materials must not simply be enclosed or drilled through in order to install insulation or a new finish over them. 

Safe renovation begins before the first demolition work

A successful renovation begins with a proper assessment of the existing materials. Particularly in a building constructed before 2001, it is advisable to have suspected asbestos applications investigated before removing roofing, facade cladding, insulation or other construction layers.

When asbestos is identified in time, its removal, disposal and the subsequent renovation can be planned safely and in the correct order. The property can then be fitted with a new roof build-up, modern insulation or a durable facade finish.

At Faccader, we take the existing construction and possible asbestos risks into account during roof and facade renovations. When suspicious materials are identified, the next stages of the work are planned only after the required professional checks and the appropriate removal method have been established.

This helps us avoid unnecessary risks and work towards a safe, durable and carefully finished renovation.