Old floor adhesives can contain asbestos. The best-known example is the dark or black bitumen-based adhesive under old vinyl flooring, used especially from the 1950s to the 1980s, but asbestos may also be present in other floor and tile adhesives used before 1994. The colour of the adhesive proves nothing either way: black adhesive is a good reason to test the floor, but light-coloured adhesive does not mean the floor is asbestos-free. You get certainty from a laboratory analysis, and the sample must include both the flooring and its adhesive.
This article covers the kinds of adhesive found in old floors, why colour does not decide anything, how to sample the flooring, adhesive and levelling compound, and what the result means for your floor renovation.
Which adhesives can contain asbestos?
Under an old floor covering there is usually a layer of adhesive that is a different product from the flooring on top. The adhesive may have contained asbestos even if the flooring does not, or the other way round.
Black flooring adhesive and bitumen adhesive
Dark, black or brownish-black bitumen-based adhesives were common under old vinyl sheet flooring and vinyl tiles. They are often tacky or tar-like and stay on the concrete when the flooring is lifted. An adhesive like this is a clear reason to test the floor before it is scraped or ground.
Other old flooring adhesives
Not all old floor adhesives are black. Yellowish, brown and light-coloured adhesives may come from different manufacturers and decades, and they too may have contained asbestos. That is why light adhesive under flooring laid before 1994 is tested in the same way as dark adhesive.
Tile and vinyl tile adhesives
Adhesives and mortars for ceramic tiles and the adhesive under old vinyl tiles can also contain asbestos. Tile adhesive is covered in more detail in the article asbestos in tile adhesive and on the page tile adhesive asbestos analysis. More on 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 is a layer of its own. In an old floor the levelling compound may also contain asbestos, so it belongs in the same assessment. More on this on the page asbestos in filler and levelling compound.
Does the colour of the adhesive show whether it contains asbestos?
No. Colour is a clue, not a result. Keep the following in mind:
- Dark or black adhesive is a reason to test, but not all black adhesives contain asbestos.
- Light-coloured adhesive is not proof that the floor is asbestos-free.
- Adhesives that look alike have been made with different compositions, so the adhesive in two floors can be different products even if they look the same.
- There may be adhesive residue from an earlier floor covering under a newer one, in which case the floor has several adhesive layers on top of each other.
Why are the flooring and adhesive tested together?
The vinyl flooring, the adhesive and the levelling compound are separate layers, and asbestos can be in any of them. If only a piece of flooring is sent without its adhesive, an asbestos-containing adhesive can be missed. That is why a floor sample must contain the flooring with the adhesive stuck to it and, if the flooring has already been removed, the adhesive on the concrete surface plus a piece of the levelling compound beneath it. Vinyl flooring is covered further in the article asbestos in vinyl flooring and on the page vinyl flooring asbestos analysis.
When should floor adhesive be tested?
Intact flooring and its adhesive do not release fibres into the air. The risk arises when the flooring is torn up, the adhesive is scraped off or the floor is ground or milled. The floor should be tested before such work if the flooring, adhesive or levelling compound dates from before 1994. If the renovation also involves pipes or insulation, see the article asbestos in mineral wool and insulation as well.
How to sample the flooring and adhesive
Take the sample in the room and from the floor that you plan to remove. If different rooms have different flooring or the floor has been repaired at different times, take a separate sample of each different floor.
- Wear disposable gloves and a respirator of at least class FFP3.
- Choose an inconspicuous spot, for example along a wall, under a cabinet or near the threshold.
- Lightly mist the sampling spot with a spray bottle to keep dust to a minimum.
- With a knife, cut out a piece of flooring of about 3 × 3 centimetres and lift it with a chisel so that the adhesive stays attached to its underside.
- Also scrape off some of the adhesive left on the floor and a small piece of the levelling compound beneath it, if there is any.
- Drop everything straight into the same zip-lock bag, seal it and put it inside a second bag.
- Mark the bag with the location and layers, for example "living room, vinyl flooring + black adhesive + levelling compound".
- Cover the sampling spot with tape and wipe the area with a damp cloth.
When all the 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 the flooring, adhesive and levelling compound as separate samples. More detailed instructions are in the article how to take an asbestos sample.
What does the result of a floor sample mean?
Onelab analyses the sample with a JEOL SEM-EDS electron microscope in accordance with ISO 22262-1, and the result is sent by email, typically on the day the sample arrives. The result tells you whether asbestos was detected in the sample you sent.
- No asbestos detected: the result applies to the floor build-up at the sampling spot and similar material. Other rooms and repaired areas with different flooring or adhesive are tested separately.
- Asbestos detected: the floor build-up is treated as asbestos-containing. Lifting the flooring and scraping or grinding the adhesive are planned as asbestos work, and the removal is carried out by a company authorised for asbestos removal work. In some cases a new floor can be laid on top of the old one, so that the old build-up is not broken up.
If the floor is part of 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 of a floor sample 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.