The Honest Answer Nobody Puts First

Search for how to identify an asbestos roof and you will get a list within seconds. Grey. Corrugated. Slightly fibrous when you look at the cut edge. Fixed with hook bolts. Brittle at the fixings.

All of that is true of asbestos cement sheeting. It is also true of the fibre cement sheeting that replaced it, which was designed to be a drop-in substitute and therefore looks and behaves the same way from six feet below.

So the visual test tells you something useful and stops short of telling you what you need. It narrows the question from “could this be asbestos?” to “this is cement sheet, so it needs testing before anyone touches it”. That is a genuinely useful narrowing. It is not an answer.

The Date Test Does More Work Than the Look Test

The single most informative thing about an old cement sheet roof is when it went on. HSE’s position is blunt: asbestos can be present today in any building built or refurbished before the year 2000.

That is the line worth holding onto, because it is a whole-building rule rather than a roofing one. A 1960s prefab garage on a Sheffield estate, a 1970s workshop behind a terrace, a lean-to that was re-sheeted in the eighties — all of them sit on the wrong side of that date.

The reverse is also useful. If you have paperwork showing the outbuilding went up in 2006, you are almost certainly looking at modern fibre cement and the conversation gets much simpler and much cheaper.

What Makes These Roofs Dangerous to Walk On

HSE’s guidance on fragile surfaces says something that surprises most homeowners: all roofs, once fixed, should be treated as fragile until a competent person has confirmed they are not. Non-reinforced fibre cement sheets are listed first among the materials likely to be fragile, ahead of rooflights, corroded metal and wired glass.

Decades of frost, moss and UV do not help. A sheet that was marginal when new is weaker now, and the weakest point is exactly where a foot naturally goes — near the fixings, at the sheet edge, on the overlap.

This is why the standing advice for anything on an old cement sheet roof, including jobs as small as clearing a gutter or freeing a downpipe, is to work from below on a platform or from crawling boards spanning the purlins, never on the sheet itself.

Testing: The Bit Worth Paying For

Sampling is not a job to improvise. Breaking a corner off a sheet with a hammer to see what is inside is the single most reliable way to turn a stable, bonded material into airborne fibre.

A proper sample is taken wet, with the area controlled and the sample double-bagged, then sent to an accredited laboratory. The report comes back naming the fibre type, and that result is what everyone downstream works from — contractor, waste carrier, tip.

Whether the removal then needs an HSE-licensed contractor or can be done as lower-risk work depends on the material and on how it is being taken apart. That is a call for the asbestos contractor to make and to explain to you in writing, and it is a fair question to put to anyone quoting: which category does my job fall into, and how did you assess that?

What a Controlled Removal Looks Like

Done properly, taking a sheeted roof off is quiet and slow, and it looks almost boring. That is the point.

Sheets come off whole rather than being broken. Fixings are cut or drilled out rather than levered. The material is kept damp so anything released stays in the water rather than the air. Sheets are lowered, not dropped, and wrapped or bagged as they come down. The area underneath is sheeted so that debris is captured rather than swept up afterwards.

What you should not see is a breaker, an angle grinder, a power washer, or anybody standing on the roof. Any of those on an untested cement sheet roof is a reason to stop the job. It is the same instinct that keeps you safe elsewhere in the trade — the reason we wrote our guide on how to spot a cowboy roofer in Sheffield applies here with much higher stakes.

Disposal: It Cannot Go in a Skip

Asbestos is named on the government’s list of hazardous waste, alongside solvents, oils and pesticides. That has practical consequences on a domestic job.

It cannot go into a general builder’s skip. It cannot be broken down to fit. It has to be double-wrapped, labelled, carried by someone registered to carry it, and taken to a site licensed to receive it. Sheffield City Council, like most local authorities, runs a specific route for householder asbestos rather than accepting it at the ordinary tip counter, and that route usually needs booking in advance.

Ask for the disposal paperwork at the end of the job and keep it. It is the only evidence you will have that the material went somewhere legitimate.

Where a Roofing Contractor Fits — and Where We Do Not

We think this is worth being straight about, because a lot of quotes blur it.

RBC Roofing are roofers. On a suspected asbestos roof our job is to look at it, tell you honestly what we think you are dealing with, tell you what needs testing before anyone works on it, and then price the roof that replaces it. The removal itself belongs to an asbestos contractor with the right assessment, the right method and the right waste route.

Sequencing the two properly is most of the value. The removal contractor leaves you with bare purlins and an open building. If nobody has planned what goes back on, you have an uncovered garage and a wait. Booking the replacement to follow on directly is the difference between a two-day job and a fortnight of tarpaulins.

What Goes Back On

Once the old sheeting is gone you are, in effect, specifying a new roof from scratch, which is a better position than most homeowners realise.

On a garage or workshop with a shallow pitch, modern profiled sheet is the like-for-like replacement and the cheapest route. Box-profile steel is lighter than the cement it replaces and goes on faster. Where the building is flat rather than pitched, a single-ply or rubber membrane is usually the sensible answer, and our page on flat roofing in Sheffield covers the options.

Where the outbuilding sits in view of the house — and on a lot of Sheffield plots the garage is very much in view — it is worth asking about a tiled or slated finish instead, which our garage roof replacement work covers regularly.

One thing to check either way: the frame. Sheeted roofs are often carried on timber purlins that have spent forty years getting damp at the wall plate. It is worth having them looked at while everything is open, because the same access will cost a great deal more to arrange twice.

If You Are Leaving It Where It Is

Undisturbed asbestos cement in reasonable condition is generally considered lower risk than badly handled asbestos cement, and there is no legal requirement on a homeowner to remove it from their own home.

Leaving it alone is a legitimate decision. Leaving it alone and forgetting about it is not. If you go that way, look at it once a year for cracking, delamination or moss growth that holds water against the sheet, keep anything heavy off it, and tell anyone who works anywhere near it — aerial fitter, gutter cleaner, solar installer — what it is before they climb up.

Common Questions

Is it illegal to remove an asbestos garage roof yourself?

Not automatically, on your own domestic property. But the practical bar is high: you would need to know from a test what you are handling, work without breaking or power-cutting the material, control the debris, and arrange licensed disposal. Most people who look honestly at that list conclude it is not worth it.

Can you tell if a roof is asbestos just by looking?

You can narrow it down. Cement sheeting on a building from before 2000 should be assumed to contain asbestos until tested. But modern fibre cement is visually very close, so a look gives you a working assumption rather than an answer. A laboratory test on a properly taken sample is the only confirmation.

Is an asbestos roof dangerous if it is not damaged?

Bonded asbestos cement in sound condition is stable, and the fibres are held in the cement matrix. The risk rises sharply when it is drilled, cut, broken, pressure-washed or walked on. That is why the advice is to leave it undisturbed and monitored rather than to poke at it.

Do I have to tell a buyer my garage roof is asbestos?

You should answer the property information questions honestly, and asbestos in an outbuilding is the sort of thing a buyer’s surveyor will raise anyway. In practice it is rarely a deal-breaker on a garage — an unexplained one usually causes more trouble than a disclosed one.

Can solar panels be fitted to an asbestos roof?

Almost never on the sheeting itself. Fixing panels means drilling the material and loading a surface that will not carry a person, so the normal answer is that the roof is replaced first and the panels go onto the new covering.