What Does "No Asbestos Detected" Mean on Your Test Result?

“No asbestos detected” means the laboratory looked at the sample you sent and found no asbestos fibres in it. That’s good news, but it’s news about the sample. It doesn’t clear the whole ceiling, the whole room or the whole house. Before you start drilling, sanding or stripping, it’s worth taking five minutes to check that the piece that was tested really is the material you’re about to disturb. Here’s how to do that.

What does “no asbestos detected” actually tell you?

On a UK lab report you’ll often see it shortened to NAD or NADIS, which stands for No Asbestos Detected In Sample. The word that matters is “sample”. The analyst examined the piece in the bag, under a microscope, using the methods set out in HSE’s asbestos analysts’ guide (HSG248), and found none of the asbestos fibre types in it.

If asbestos had been found, the report would name the type instead, usually chrysotile (white), amosite (brown) or crocidolite (blue).

So a clear result is a reliable answer to one question: was there asbestos in that piece of material? It’s a much weaker answer to the question most people are really asking, which is whether it’s safe to start work.

Why does a clear result cover only the sample and not the whole house?

Because building materials aren’t uniform, and houses get patched, repaired and redecorated over decades. A few common ways a clear sample can mislead:

• Patches and repairs. A textured ceiling may have been patched with a newer coating in one corner. A sample from the patch says nothing about the original.
• Layers. Floors often have tiles on top of adhesive on top of older tiles. Walls and ceilings can have one coating painted over another. A sample that only took the top layer leaves the rest unknown.
• Similar looking materials. Two Artex ceilings in the same house can look identical and be from different decades.
• Areas nobody sampled. Lofts, under stairs cupboards, boxed in pipes, the garage and outbuildings are all easy to miss.

Textured coatings applied before 2000 can contain asbestos, but plenty don’t, and you can’t tell by looking. That’s exactly why the result needs to match the material.

How do you check the sample matches what you plan to disturb?

Run through this checklist with your report in one hand before you act on a clear result:

Your clear result checklist

If every row matches, you can go ahead with far more confidence. If one doesn’t, that’s the gap to close first.

When is it worth taking another sample?

Take another sample when:

• The work will reach a room, ceiling or floor that wasn’t sampled
• You’re lifting flooring and only the top tile was tested, not the black adhesive underneath
• The material you’re disturbing looks different in colour, texture or thickness from the area that was tested
• You find something unexpected once work starts, like boarding behind a wall or an older floor under a newer one

If you find something unexpected mid job, stop work on that material and get it checked. A short pause costs far less than disturbing something you shouldn’t have.

For a bigger job, such as a full kitchen, bathroom or loft conversion, a single sample may not be enough. HSE’s asbestos survey guide (HSG264) sets out how surveys are planned and carried out before refurbishment work, and it’s a useful read if your project touches several rooms.

What should you give your builder along with the result?

HSE’s asbestos questions and answers advise homeowners to tell builders and contractors about asbestos in the home before they start work. A clear result is part of that conversation too. Give your builder:

• The certificate itself, not just a photo of the result line
• The sample references and where each one was taken from
• Photos of the sampled spots, if you have them
• A plain note of what the job involves and which materials it will disturb

That lets them check for themselves that the result covers their work, and spot anything that still needs testing before they start.

Frequently asked questions

What does NAD or NADIS stand for on a lab report?

NAD means No Asbestos Detected. NADIS means No Asbestos Detected In Sample. They mean the same thing: the laboratory found no asbestos fibres in the piece of material it was sent.

Is “no asbestos detected” the same as asbestos free?

Not for the whole property. It means that sample was clear. Other materials, other rooms and hidden layers can still contain asbestos, which is why the checklist above matters.

Do I need to keep the certificate?

Yes, keep it. It’s useful when builders quote, if you sell the house, and if you ever need to show that a material was checked before work began. Keep it with any photos of where the sample was taken.

Can similar Artex in another room be assumed clear?

No. Two ceilings that look the same can be from different times or have been patched differently. If you’re going to disturb another ceiling, get that one sampled too. If it’s the same job, it often makes sense to take both samples on the same visit.

Not sure your sample covers the job?

If the material you’re about to disturb wasn’t the one that was tested, book a further sample. We take it with care and send it to a UKAS-accredited laboratory, and results typically come back within 24 to 48 hours. If a ceiling does turn out to contain asbestos, see our asbestos Artex ceiling removal page and our Artex ceiling removal cost guide. For a garage or shed, our guide on whether an asbestos garage roof is safe to leave walks you through the decision.

You can also send us your report and a couple of photos through our free quote form, and we’ll tell you honestly whether we think it covers your job. We cover towns across Berkshire, Surrey and Hampshire.