Asbestos cannot be reliably identified by sight. An asbestos-containing filler, tile adhesive or board looks exactly like the same product without asbestos, because the fibres are microscopic and mixed into the material. The age of the building and the type of material tell you whether asbestos is possible, but the only way to be certain is to have a sample of the material analysed in a laboratory.
This article explains why asbestos cannot be recognised by its appearance, what typical suspect materials look like and where they are found, how to tell an asbestos sheet from other boards, and how a suspicion is confirmed.
Why can't asbestos be identified by eye?
Asbestos is a fibrous mineral that was added to building products to make them stronger, more durable and more fire resistant. Individual asbestos fibres are so thin that they cannot be seen with the naked eye. In a finished product the fibres are bound into cement, adhesive, filler or plastic, and the colour and surface of the product come from the binder and pigments, not from the asbestos.
The same product was often made both with and without asbestos over the years. Two tile adhesives or vinyl floorings that look identical can therefore have a different composition. Appearance alone does not tell you which version is in the building.
Colour, smell and home tests tell you nothing
- Colour: people often speak of white, blue and brown asbestos. These names refer to the colour of the raw minerals, not to what a finished building product looks like. An asbestos-containing filler can be white, grey or beige like any other filler. More on the types on the page types of asbestos.
- Smell: asbestos has no smell. The smell of an old material comes from adhesive, damp or solvents, not from asbestos.
- Home tests: there is no reliable chemical quick test or other DIY test for asbestos. Burning, wetting or crumbling the material, or looking for fibres with a magnifying glass, tells you nothing about asbestos, and breaking the material can instead release fibres into the air.
What do materials that may contain asbestos look like?
In practice, identifying asbestos means recognising suspect materials. The following are typical if the building was built or renovated before 1994. A longer list is in the article where can asbestos be found.
Fillers and sprayed surfaces
Wall and ceiling fillers are usually a white or grey, hard and fine-grained compound, often in several thin coats under paint or wallpaper. Sprayed, grainy or textured ceiling and wall finishes belong to the same group. Read more on the page asbestos in filler.
Tile adhesives and mortars
The adhesive behind tiles is often a grey or pale, hardened compound that only becomes visible when a tile comes off. Grout and bedding mortar can also contain asbestos. More on the page asbestos in tile adhesive.
Vinyl flooring, vinyl tiles and black adhesives
Old vinyl sheet flooring, small square vinyl tiles and the adhesive beneath them are common suspect materials. A black or dark brown, bitumen-like floor adhesive is a particularly typical find under an old floor. See the pages asbestos in vinyl flooring and asbestos in vinyl tiles and the article asbestos in flooring adhesive.
Pipe insulation
Old insulation on heating pipes is often a white, grey or yellowish compound with a cloth, cardboard or painted surface. Mouldable insulating compound was used especially at bends and joints. More on the page asbestos in pipe insulation.
Roofing felt, sealants and fire protection
Asbestos was also used in bituminous roofing felt and roof coatings, in sealants around windows and between building panels, and in fire protection, for example around fireplaces, in fire doors and in board linings of technical rooms. Roofing felt is covered on the page asbestos in roofing felt.
How to identify asbestos sheets
An asbestos-cement sheet is typically a grey, hard and heavy board used on facades, corrugated roofs, in wet rooms and for fire protection. A broken edge may sometimes show a fibrous structure, but that is not enough to identify asbestos: newer fibre-cement boards look much the same and use other fibres instead of asbestos. The age of the board, where it is used and how it is fixed can strengthen a suspicion, but only an analysis gives certainty. More in the article asbestos cement.
How do you know if there is asbestos?
When your eyes are not enough, the assessment is based on a few questions and confirmed with a sample.
- Age: was the building built, or the material installed, before 1994? Later renovations should not contain asbestos, but older layers can be hidden under new surfaces.
- Type of material: does the material belong to one of the groups above, such as fillers, adhesives, floorings, insulation or boards?
- Documents: building drawings, a maintenance manual or an earlier asbestos survey can tell you which materials were used or what has already been tested.
- Sample: if the material is going to be demolished, sanded or drilled and asbestos is possible, a sample is taken and analysed in a laboratory.
An intact, undisturbed material does not release fibres into the air, so a suspicion does not usually call for urgent action. The information is needed before the material is broken. The health effects of exposure are covered in the article symptoms of asbestos exposure.
How is asbestos confirmed in the laboratory?
You can take the sample yourself: remove a small piece of about 2–5 centimetres with all its layers and pack it in two sealed bags. Protection and tools for sampling are covered in the article how to take an asbestos sample.
Onelab analyses the sample with a JEOL SEM-EDS electron microscope in accordance with the ISO 22262-1 standard. The electron microscope shows the shape of the fibres and the elemental analysis shows their composition, so asbestos and its type can be told apart from other fibres. The result is sent by email, typically on the day the sample arrives. How to read the result is explained in the article interpreting an asbestos result.
If the work is a larger renovation or demolition that requires an on-site asbestos survey, the survey is carried out on site by a qualified surveyor. Onelab is a laboratory, and on-site surveys are handled by our sister brand AsbestiPro.
How much does the analysis cost?
The analysis costs €39.90 + VAT per sample, and the price is the same for 1–100 samples. Orders of more than 100 samples can be priced separately. Postage is not included. You can order the analysis online and send the sample to the laboratory by post.