Old floor adhesives can contain asbestos. The best-known example is the dark or black bituminous adhesive under old vinyl (PVC) floor coverings, used mainly from the 1950s to the 1970s. But asbestos can also be found in other floor and tile adhesives from before asbestos was banned. The colour of the adhesive proves nothing either way, though: black adhesive is a good reason to have the floor tested, but light-coloured adhesive does not mean the floor is free of asbestos. Only a laboratory analysis gives you certainty, and the sample should include both the floor covering and the adhesive.
In this article we go through which adhesives are found in old floors, why the colour is not decisive, how to take a sample of the floor covering, adhesive and levelling compound, and what the result means for your floor renovation.
Which adhesives can contain asbestos?
Under an old floor you will often find a layer of adhesive that is a different product from the floor covering on top. The adhesive may contain asbestos even if the floor covering does not, or the other way round.
Black floor adhesive and bitumen adhesive
Dark, black or brownish-black bituminous adhesives were common under old vinyl floor coverings and vinyl floor tiles. They are often tough or tar-like and stay stuck to the concrete when the floor covering is removed. Such an adhesive is a clear reason to test the floor before it is scraped or sanded off.
Other old floor adhesives
Not all old floor adhesives are black. Yellowish, brown and light-coloured adhesives may be products of different manufacturers and different decades, and they too may have contained asbestos. That is why a light-coloured adhesive under a floor covering laid before the asbestos ban is tested in exactly the same way as a dark one.
Tile adhesive and adhesive for vinyl tiles
Adhesives and mortars for wall and floor tiles, as well as adhesives for old vinyl floor tiles, can also contain asbestos. Tile adhesive is described in more detail in the article Asbestos in tile adhesive and on the page Asbestos analysis of tile adhesive. You can read more about vinyl tiles on the page Asbestos in vinyl tiles.
Levelling compound under the adhesive
Under the adhesive there is often a floor levelling compound, which forms a separate layer. In an old floor the levelling compound can also contain asbestos, so it belongs in the same investigation. More on this on the page Asbestos in filler.
Does the colour of the adhesive show whether it contains asbestos?
No. The colour is a clue, not a result. Keep the following in mind:
- Dark or black adhesive is a reason to test, but not every black adhesive contains asbestos.
- Light-coloured adhesive is no proof that asbestos is absent.
- Adhesives that look the same were made with different compositions, so the adhesive in two floors may be different products even if it looks identical.
- Under a newer floor covering there may be adhesive residues from an earlier floor; in that case the floor has several layers of adhesive on top of one another.
Why are the floor covering and adhesive tested together?
The vinyl floor covering, adhesive and levelling compound are separate layers, and asbestos can be in any of them. If you only send in a piece of floor covering without adhesive, an adhesive containing asbestos may be missed. That is why a floor sample should include the floor covering and the adhesive stuck to it – and if the floor covering has already been removed, the adhesive on the concrete and a piece of the levelling compound underneath. Vinyl floor coverings are described in more detail in the article Asbestos in vinyl flooring and on the page Asbestos analysis of vinyl flooring.
When is it worth testing the floor adhesive?
An intact floor covering with its adhesive does not release fibres into the air. The risk arises when the floor covering is torn up, the adhesive is scraped off or the floor is sanded or milled. Before such work, testing is worthwhile if the floor covering, adhesive or levelling compound dates from before asbestos was banned in your country (2005 at the latest across the EU, and earlier in many countries). If the renovation also involves pipes, read about asbestos in pipe insulation as well.
How to take a sample of the floor covering and adhesive
Take the sample in the room and from the floor you want to remove. If different rooms have different floor coverings, or the floor has been patched at different times, take a separate sample from each floor that looks different.
- Wear disposable gloves and a respirator of at least class FFP3.
- Choose a spot that is out of sight, for example along a wall, under a cupboard or near a door threshold.
- Lightly moisten the sampling spot with a spray bottle to keep dust to a minimum.
- Use a knife to cut out a piece of floor covering of about 3 × 3 centimetres and lift it with a scraper or chisel so that the adhesive stays stuck to the underside of the floor covering.
- Use the chisel to also scrape off adhesive left on the floor and a small piece of the levelling compound underneath, if there is any.
- Put everything straight into the same resealable plastic bag, seal it and place it in a second bag.
- Write the location and layers on the bag, for example "Living room, vinyl floor + black adhesive + levelling compound".
- Cover the sampling spot with tape and wipe the surface with a damp cloth.
When all layers are in the same bag, the result applies to the whole floor build-up. If you want to know which layer contains the asbestos, you can send in the floor covering, adhesive and levelling compound as separate samples. You will find more detailed instructions in the article How to take an asbestos sample.
What does the floor sample result mean?
Semlab analyses the sample with a JEOL SEM-EDS electron microscope in accordance with ISO 22262-1, and you receive the result by email, usually on the same day the sample arrives at the laboratory. The result shows whether asbestos was detected in the sample you sent.
- No asbestos detected: the result applies to the floor build-up the sample came from and to identical material. Other rooms and patched areas with a different floor covering or adhesive are tested separately.
- Asbestos detected: the floor build-up is treated as containing asbestos. Removing the floor covering and scraping and sanding off the adhesive are planned as asbestos work, and the demolition is carried out by a specialist asbestos removal contractor. Sometimes a new floor can be laid on top of the old one so that the old build-up does not have to be broken up.
If the floor is part of a larger renovation or demolition that requires an on-site asbestos survey, that is done by a surveyor. Semlab is a laboratory and does not carry out on-site surveys.
How much does analysing a floor sample cost?
The analysis costs €49.99 incl. VAT per sample. The price is the same for 1–100 samples. Postage is not included. You can order the analysis online, pay by card and send the sample as a letter or small parcel with your national postal service to the laboratory in Finland.