Asbestos in paint: which paints and coatings should be tested?

Old paint can contain asbestos if the surface was painted before 1994. Asbestos was used above all in paints and thick coatings for facades and other mineral surfaces, in bitumen paints and coatings, and in some special paints such as anti-corrosion paints. You cannot tell by looking at paint whether it is asbestos-free. You get certainty from a laboratory analysis, and the sample should include both the paint and the filler or substrate underneath it, because sanding old paint often breaks the surface below as well.

This article covers which paints and coatings may contain asbestos, which painting jobs break the old surface and which do not, how to take a sample of the paint layers, and what the result means for the painting work.

Which paints and coatings can contain asbestos?

Paint is rarely a single layer. An old surface often has a primer, several topcoats from different decades and, beneath them, filler, render or a board. Asbestos can be in any of these.

Facade paints and thick coatings

In Finland, asbestos was used above all in paints and thick, rough coatings for concrete, lightweight concrete, render and asbestos cement. They were used not only on facades but also indoors, for example on rendered surfaces. Asbestos was less common in ordinary interior paints. Such coatings are usually thicker than an ordinary paint film, and in practice the line between paint and filler is blurred. The layers of a wall are covered in the article asbestos in walls, and fillers on the page asbestos in filler.

Bitumen coatings and paints

Black or dark brown bitumen paints and coatings were used to treat and patch felt, metal and concrete roofs, and bitumen emulsions and solutions for damp-proofing, for example on foundation and basement walls. Asbestos was added to them as a filler. Bitumen roofing products are covered on the page asbestos in roofing felt.

Anti-corrosion and metal paints

Asbestos was also used in special paints, for example for corrosion protection and for painting metal surfaces. In boiler and heat distribution rooms, painted pipes and equipment may also have insulation or fire protection under the paint, which are separate materials. They are covered in the article asbestos in fire protection.

Paint on top of an asbestos-containing material

Often the asbestos is not in the paint but under it. A painted asbestos cement board on a facade, painted pipe insulation or painted old filler looks like an ordinary painted surface, but when the paint is sanded or scraped, the material underneath breaks too. Asbestos cement boards are covered in the article asbestos cement.

Which painting jobs break the old surface?

An intact paint surface does not release fibres into the air. What matters is what you plan to do to it. The stages of a painting job differ a great deal.

• Machine sanding produces the most fine dust, and it easily goes through the paint into the filler or board.
• Scraping loosens flakes and dust, especially when the paint is dry and brittle.
• Heat guns and chemical strippers soften the paint, so less dust is produced, but the stripped paint is still the same material. If the paint contains asbestos, this waste contains asbestos too.
• Pressure washing and blasting of facades and roofs strip the surface over a large area and spread the loosened material around.
• Painting over old paint without sanding or scraping does not break the old surface. If the surface still has to be keyed or flaking areas removed, test the material first.

Flaking, peeling old paint is already damaged. Do not brush up loose flakes or vacuum them with an ordinary vacuum cleaner. Pick them up with a damp cloth until you know what the material contains.

How to take a sample of paint

Take the sample from the surface you plan to sand, scrape or wash. If different surfaces have different paint, for example a textured coating on the ceiling and smooth paint on the walls, or if parts of a facade were painted at different times, take a separate sample from each.

1. Wear disposable gloves and a respirator of at least class FFP3. Safety glasses are a good addition if you are sampling a ceiling.
2. Lightly mist the sampling spot with a spray bottle to keep dust to a minimum.
3. Hold an open zip-lock bag under the spot so that any flakes fall straight into it.
4. If the substrate is filler or render, cut out a piece of about 2–5 centimetres with a knife, deep enough that every paint layer and a piece of the filler underneath come with it.
5. If the substrate is hard, such as concrete or metal, scrape the paint layers off down to the substrate over an area of a few centimetres and collect all the flakes in the bag. Thin paint needs a slightly larger area to give enough material.
6. If the paint is on a board, do not try to scrape the paint off separately. Take a sample of the board with its surface layers, so the result covers both.
7. Seal the bag, put it inside a second bag and mark it with the location and layers, for example "bedroom, ceiling, textured coating + filler".
8. Cover the spot with tape or paint and wipe the area with a damp cloth.

When the paint and the substrate are in the same bag, the result covers the whole surface build-up. If you want to know whether the asbestos is in the paint itself, you can send the paint flakes and the substrate as separate samples. Protective equipment is covered in more detail in the article how to protect yourself when taking an asbestos sample.

What does the result of a paint 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: no asbestos was detected in the paint layers or substrate of the sample. The result applies to the sampling spot and similar surfaces. Surfaces painted at different times and repaired areas are tested separately.
• Asbestos detected: the surface build-up is treated as asbestos-containing. Sanding, scraping and paint removal are planned as asbestos work, and the removal is carried out by a company authorised for asbestos removal work. If the surface does not need to be broken, a new coat of paint may be possible without removing the old one.

Besides asbestos, old paints can contain other hazardous substances such as lead. An asbestos analysis only tells you about asbestos.

If the painting 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 paint 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.