Asbestos cannot be reliably identified by eye. The fibres are microscopic, and the same material was often made both with and without asbestos. The type of material, its year of manufacture and the age of the building can still give you good reason to suspect it, and certainty comes from a laboratory analysis, either of a sample you take yourself or as part of an asbestos survey.
What does asbestos look like in building materials?
Raw asbestos is a fibrous mineral, but you will almost never see it in that form inside a building. The fibres are mixed into cement, adhesive, plaster, plastic or bitumen and are far too thin to see with the naked eye. Asbestos-containing plaster looks like ordinary plaster, and asbestos vinyl flooring looks like ordinary vinyl flooring. In practice, identifying asbestos therefore comes down to three things: what kind of material it is, when it was made or installed, and what it looks like when it breaks.
The single most important clue is age. Asbestos stopped being used in building materials in Finland by 1994 at the latest. If a building was completed or renovated before then, its original materials should be treated as potentially containing asbestos until proven otherwise. For a broader overview of where asbestos tends to turn up in a building, see where asbestos is found.
Besides the construction year, it pays to find out the renovation history. In an old house some surfaces may already have been replaced with asbestos-free materials, while a newer building can contain older materials that were reused or installed from old stock. Information from the property manager or previous owner, old drawings and renovation records help you work out which surfaces are original.
How do you identify asbestos in different materials?
The list below covers the most common suspect materials in the format material → typical period of use → what raises suspicion. The decades are indicative only: old stock was used later, and asbestos can also turn up in materials not on this list.
- Asbestos cement sheets (Minerit, corrugated sheets, small fibre-cement roof slates) → mostly the 1950s–1980s → a grey, hard, brittle board that snaps with a sharp edge; fine fibres may be visible on the broken edge.
- Vinyl flooring and vinyl tiles → especially the 1960s–1970s → thin sheet flooring with a felt-like backing, or small square tiles with dark adhesive underneath.
- Floor and tile adhesives → 1950s–1980s → hard black or dark brown bitumen adhesive under the floor covering, or grey tile mortar behind old wall tiles.
- Wall and ceiling plasters and fillers → 1960s–1980s → original plaster or filler on concrete or board surfaces, especially in bathrooms, kitchens and on ceilings.
- Pipe insulation → 1950s–1970s → white or grey, plaster-like insulation compound on pipe bends and joints, often under a cloth or paper wrapping.
- Roofing felt and bitumen membranes → 1960s–1980s → several layers of felt on top of each other on flat roofs, terraces and balconies.
- Window putty and sealants → 1950s–1970s → hard, cracked putty in old timber windows and hardened sealant in the joints between concrete panels.
- Paints and textured coatings → 1960s–1980s → a rough, sprayed-on textured finish on ceilings or walls that is clearly original.
What does asbestos sheeting look like?
Asbestos sheets raise the most questions, because they are in plain sight on roofs, facades and outbuildings. An old asbestos cement sheet is usually grey or painted, slightly rough on the surface and, outdoors, often covered in moss. It is hard but brittle: the edge snaps off cleanly and the sheet does not bend. Markings on the back or edge may indicate when it was made, but a missing marking proves nothing. The difficulty is that asbestos-free fibre-cement sheets made later look almost identical. The differences between board types are covered in asbestos boards: Luja board, fibre cement or Minerit, and Minerit in particular in Minerit sheets and asbestos.
Which signs are not enough to identify asbestos?
Many people try to judge by colour, surface or condition. None of these is a reliable sign:
- Colour: asbestos-containing material can be grey, white, black, brown or painted any colour.
- Visible fibres: a fibrous broken edge raises suspicion, but glass fibre, cellulose and mineral wool look fibrous too. In a dense compound, on the other hand, asbestos fibres cannot be seen at all.
- What the product looks like: the same product may have been made looking exactly the same both before and after asbestos was phased out.
- Condition: an intact surface says nothing about composition. Condition only affects how easily fibres are released.
Do not try to find out by breaking, sanding or scraping the material over a large area. Working the material is exactly what releases fibres into the air.
How do you confirm suspected asbestos?
Once you suspect asbestos, there are two ways to find out for certain:
- A sample you take yourself. If only one or a few materials are involved, you can take a small sample yourself and post it to the laboratory. The analysis costs 39,90 € + VAT per sample and is carried out with a JEOL SEM-EDS electron microscope in accordance with the ISO 22262-1 standard. Read more about the asbestos sample.
- An asbestos survey. The Finnish Asbestos Act (684/2015) and Government Decree 798/2015 on the safety of asbestos work require a survey before renovation and demolition work in buildings built before 1994 or containing materials from before 1994. The surveyor inspects the property, samples every suspect material and writes a report. Depending on the city, a survey costs from 119 € incl. VAT, and the price covers the survey, all samples, the analysis, travel and the report. For demolition projects, 100 € is added.
We carry out on-site surveys in Southern Finland. Elsewhere in Finland, the practical option is to take the sample yourself and send it by post.
What should you do while waiting for the result?
Treat the suspect material as if it contains asbestos. Leave it alone, do not drill, saw or sand it, and do not pressure-wash an old sheet roof. Intact material does not usually pose an immediate hazard as long as it is not worked on. If the result is negative, the renovation can go ahead as normal. If asbestos is found, removing the material is asbestos removal work carried out by a company authorised to do it. The lab result or survey report tells the removal contractor which materials the work involves. For a larger renovation, you can order an asbestos survey online.