Asbestos sheets is an everyday name for several types of board that contain asbestos fibre: asbestos cement sheets such as Minerit and Eternit, older Luja boards and fibre-cement boards, and some fire-protection, acoustic and bitumen boards. Whether a board contains asbestos depends above all on when it was made: a board made before 1994 may contain asbestos, one made later does not. Because old and new boards often look the same, only a laboratory analysis gives you certainty.
Which boards count as asbestos sheets?
Asbestos was added to boards because it improved strength, weather resistance and fire resistance. Below are the most common board types people mean when they talk about asbestos sheets or asbestos board.
Minerit and Eternit: asbestos cement sheets
An asbestos cement sheet is a hard, grey board pressed from cement and asbestos fibre. Minerit and Eternit have become almost generic names, and the sheets were used as corrugated roofing, as flat sheets on facades, balconies and plinths, and indoors in bathrooms and around fireplaces and stoves. How to recognise Minerit, what applies to roofs made of small fibre-cement slates, and the risks of an intact roof are covered in detail in Minerit sheets and asbestos.
Luja board
Luja board and asbestos is a common question, because Luja boards were widely used for interior linings, fire protection and wet rooms. Older Luja boards may contain asbestos; later ones do not. You cannot tell which you have by looking at it, so the installation year and a sample decide.
Fibre-cement boards
Fibre cement is a broader product group that also includes asbestos cement sheets. When asbestos was phased out, manufacturers switched to other fibres, and today's fibre-cement boards are asbestos-free. They still look very similar to the old ones: a grey, hard, cement-based board. That is why the answer to the question of fibre cement board and asbestos is always the same: if the board was installed before 1994, or the installation year is unknown, it has to be tested before anyone works on it.
Bituliitti board
Bituliitti is a bitumen-based windbreak and sheathing board, and the same name is also used for black bitumen adhesive. Asbestos was used in both. How to recognise them and the risks during a floor renovation are covered in a separate article, Bituliitti and asbestos.
Fire-protection boards and acoustic boards
Fire-protection boards were used around chimneys, heating appliances, electrical rooms and fire doors. Acoustic boards, meaning sound-absorbing ceiling tiles, were installed in offices, schools and other public buildings. Both groups include asbestos-containing and asbestos-free products that look identical.
Where were asbestos sheets used?
- Roofs: corrugated sheet roofs on detached houses, saunas, garages and farm buildings, as well as roofs made of small fibre-cement slates.
- Facades: flat and profiled cladding sheets, plinth boards, eaves and balcony panels.
- Wet rooms: wall boards behind the tiling in bathrooms and saunas.
- Fireplaces and heating appliances: protective boards around sauna stoves, ovens, boilers and chimneys.
- Technical rooms: fire protection in electrical and boiler rooms, and board structures connected to the ventilation system.
- Ceilings: acoustic tiles and suspended ceiling boards in offices and public buildings.
In outbuildings such as saunas, garages and sheds, the boards have often been left in their original state even when the main building has already been renovated.
Why does the age of the board matter so much?
Asbestos cement sheet production moved over to asbestos-free fibres in the second half of the 1980s, and the use of asbestos in building materials ended in Finland by 1994 at the latest. That is why the building's completion year, the board's installation year and any renovation records tell you the most. A few rules of thumb:
- A board installed before 1994 is treated as potentially containing asbestos until an analysis shows otherwise.
- If the installation year is unknown, the board should be tested even if the building is newer. Old boards may have been reused or installed from old stock.
- A fibrous broken edge, a grey cement-like mass and brittleness are clues, not proof. For more on recognising asbestos, see what asbestos looks like.
How can you tell an asbestos sheet from an asbestos-free one?
There is no reliable visual difference. Asbestos-containing and asbestos-free fibre-cement boards are both hard and cement-grey, and both give off dust when cut. The following information helps you judge whether a board should be tested:
- Records from the time of installation: drawings, renovation receipts or the housing company's maintenance history show when the boards were installed.
- Markings: there may be manufacturer's markings on the back or edge of the board, but their absence tells you nothing.
- Surrounding structures: if the building was completed before 1994 and the other surfaces are original, the boards are probably original too.
If any of these leaves you unsure, a sample is the most affordable way to get a definite answer.
How do you test an asbestos sheet?
Testing an asbestos sheet is straightforward when it is done correctly:
- A single board: wear a respirator and gloves, dampen the sampling spot and remove a small piece from the edge of the board or from a spot that is already damaged. Pack the sample in a sealable bag and send it to the laboratory. An asbestos sample costs 39,90 € + VAT and is analysed with a JEOL SEM-EDS electron microscope.
- Renovation or demolition: if removing the boards is part of renovation or demolition work in a building built before 1994 or containing materials from before 1994, the Finnish Asbestos Act (684/2015) and Government Decree 798/2015 require an asbestos survey. An asbestos survey costs from 119 € incl. VAT depending on the city, 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 sample is sent by post. AsbestiPro carries out surveys and sample analyses, not removal work. If asbestos is found, removing the boards is asbestos removal work, and the removal contractor prices the job based on the lab result or the survey report.
Can you leave an old asbestos sheet in place?
An intact asbestos cement sheet that stays in place does not usually release significant amounts of fibres. The risk arises when the sheet is drilled, sawn, sanded, broken or pressure-washed. If the board can stay, leave it alone and plan any new structures so that the old board does not need to be touched. When you do intend to work on it, find out what it contains first.