Is my garage roof asbestos?

The short answer

If your garage was built before 2000 and the roof is grey corrugated sheeting that looks like hard cement rather than metal or plastic, there’s a real chance it contains asbestos. HSE lists profiled asbestos cement sheeting as a common outside material on houses and garages in HSE’s building diagrams.

You can’t be certain by looking. Fibre cement sheets made after the ban look very similar. The only way to know is to have a sample analysed by a lab, or to treat the roof as asbestos and plan accordingly.

Signs that suggest asbestos cement

• Age. Blue and brown asbestos imports were banned in 1985 and white asbestos in 1999. A garage built before 2000, and especially before the mid-1980s, is more likely to have it.
• The look of the sheet. Grey, cement-like corrugated or wide-profile sheets, often dulled or stained with age. Many are covered in moss or lichen.
• Weight and feel. Cement sheets are rigid and heavy, unlike plastic or bitumen sheets. You shouldn’t handle them to find out, though.
• Edges. A broken or weathered edge can look rough and grey, sometimes with fibres visible. Don’t touch or pick at it.
• Matching parts. Grey cement gutters, downpipes, ridge pieces or a cement panel on the side of the garage often go with a cement roof.
• Labels or stamps. Some sheets carry manufacturer marks or date codes on the underside. If you find one, photograph it from a distance. A mark can help, but don’t rely on it alone.

What you can’t tell by eye

Asbestos fibres are far too small to see. HSE notes that asbestos is often mixed with other materials, and it publishes HSE’s photo gallery of asbestos materials so people know what to look out for, not so they can confirm it by sight. In particular:

• Fibre cement sheets made after 1999 use other fibres and look much the same.
• You can’t tell from the colour or condition which type of asbestos is present.
• Painted or coated sheets hide the surface completely.
• Some garages have asbestos insulating board inside, for example on walls or as a ceiling lining. That is a different, more fragile material, and most work on it needs a contractor holding an HSE licence.

How to get it tested

There are two common routes.

1. A surveyor or trained operative takes the sample. They damp the area, take a small piece using suitable protection, seal the hole and bag the sample. It goes to a lab accredited to ISO/IEC 17025 for analysis. HSE’s HSE’s Asbestos essentials introduction (A0) talks about having a sample “taken by a competent person and analysed”.
2. A postal testing kit. You take the sample yourself and post it to a lab. This is cheaper, but you are the one disturbing the material. See asbestos testing costs for prices and the safety points.

The result will say whether asbestos was detected in that sample and, if so, which type. A garage roof is usually one material, so one sample is often enough. Tell the lab or surveyor where it came from.

The other option is to skip testing and presume the roof contains asbestos. If you plan to remove it anyway, many people do just that and have it removed as asbestos cement.

What not to do

Asbestos cement is fairly stable while it’s left alone. Most of the risk comes from what people do to it.

• Don’t break it. Smashing sheets to get them off, or dropping them, releases fibres and turns a non-licensed job into a messier and possibly notifiable one.
• Don’t drill or cut it with power tools. That creates fine dust. HSE has specific task sheets for trained workers doing this.
• Don’t jet-wash it. HSE task sheet A12 says high-pressure jetting is only appropriate “in exceptional circumstances”, and needs a specialist contractor. Pressure washers blast fibres and slurry over the garden.
• Don’t scrub or wire-brush moss off. Abrading the surface releases fibres. HSE advises gentle scraping with the surface kept wet, for trained workers.
• Don’t walk on it, and don’t lean a ladder on it. HSE says cement roofs “are always fragile and cannot bear weight”. Falls through fragile roofs cause serious injuries and deaths, whether or not asbestos is involved.
• Don’t put pieces in your household bin or a skip. Asbestos waste must not be mixed with normal household waste. Ask your local council or a contractor.

What to do instead

• If the roof is in reasonable condition and you aren’t planning work, you can leave it and keep an eye on it. HSE’s advice is to leave materials in good condition alone and check them from time to time.
• If it is cracked, leaking or breaking up, plan for repair or removal. Our guide on whether to repair, paint or replace explains the options.
• If a sheet is already broken, keep people and pets away from the debris, don’t sweep it up dry, and get advice. HSE’s HSE task sheet A12 and A11 show how trained workers deal with debris.
• Before selling, demolishing or converting the garage, get a test or a survey so you know what you are dealing with.

If you’re worried about exposure

Brief contact with an intact cement roof is very low risk. If you have broken, drilled or jet-washed a roof you now think was asbestos, stop, keep the area damp and closed off, and get advice. If you’re worried about your health, speak to your GP and tell them what happened and when. See NHS guidance on mesothelioma and our guide on what to do if you’ve been exposed.

How we can help

We take samples for lab analysis and remove asbestos cement garage roofs across London and the South East. Send us photos of the roof, the inside and the access, and we’ll tell you what we think it is and what the options are. See asbestos testing and garage roof removal, or ask us for a quote.

Quick answers

Is every grey corrugated roof asbestos?

No. Fibre cement and other sheets made after 1999 look similar. Age and appearance only make it more or less likely.

Is an asbestos garage roof dangerous?

In fair condition and left alone, the risk is low. The risk rises when sheets are broken, drilled, sanded, jet-washed or badly weathered.

Can I tell from a photo?

A photo can help a surveyor judge how likely it is and plan sampling. It can’t confirm asbestos.

How much does testing cost?

See our testing cost guide for published price ranges.

This guide is general information, not legal advice. For the law itself, see the Control of Asbestos Regulations 2012 and HSE’s asbestos pages. Not sure what you’re dealing with? Ask us.