Garage roof replacement: what it really costs

Replacing a garage roof typically costs between £4,500 and £6,500 once you include removing the old garage door and fitting a new one, taking off an asbestos roof, re-trussing, and putting new sheets on. That surprises most people, and the reason is structural rather than greedy: taking a roof off while leaving the walls standing is a harder job than demolishing the whole building.

Nucrete does not replace garage roofs and does not do refurbishment work. We manufacture and install new buildings, remove old ones, and lay concrete bases. This page exists because we are asked about roof replacement constantly, and the honest answer is worth more than a sales pitch: here is what the job really involves, who you will need, and how it compares with starting again.

Because you are working around the building instead of through it.

Demolishing a whole garage is straightforward. Everything comes down, in order, and nothing has to stay standing. Take only the roof off and the walls have to survive the process — which means the structure is inherently unstable while the work happens, since the roof is part of what was holding the panels true. The job has to be worked around the old walls rather than driven through them, and that slows everything down.

It also brings access equipment. Not a full multi-height scaffold on a domestic garage, but usually a trestle system built around the building, and that is a cost most people have not budgeted for when they picture a couple of days' work.

This is the single reason refurbishment quotes come back higher than expected, and it is not something a homeowner can reasonably guess at from the outside.

How far the price runs up the range depends almost entirely on how far you take the job. A genuinely minor repair can be cheap and sensible, and sometimes you get lucky. It is the full strip-and-rebuild that lands at the top of that bracket.

A lot of roofers will offer felt, and felt on a garage has a working life of about four or five years. That is worth knowing before you accept the cheapest quote, because a felt roof fitted today is a job you will be paying for again before the decade is out.

Ask what the covering is, and ask what it is guaranteed for. If the answer to the second question is vague, treat the first answer as the whole story.

This is the part that catches people out, because a garage roof replacement is not one trade's job:

• A local builder or joiner for the structural work and the re-trussing. • A licensed asbestos removal contractor for the old roof, if it is asbestos cement. • A garage door company for the door, if you are replacing it at the same time.

Each one quotes separately, each one needs scheduling around the others, and each one's work depends on the previous one finishing. If the asbestos contractor runs late, the roofer stands down. If the roofer finds the walls are worse than expected, the door fitter waits.

None of that is a reason not to do it. It is a reason to get all three quotes before you commit to any of them, because the total is what matters and it is usually higher than the first quote suggests.

Put a new roof on a forty-year-old building and ask who stands behind it.

If water appears in a corner eighteen months later, the roofer can reasonably say it is coming through the old panels, and the panels have no guarantee at all because they were installed decades ago by somebody else. Both positions are arguable, which in practice means nobody is responsible and you pay again.

That is not a criticism of roofers. It is the honest consequence of joining new work to an old structure, and it is worth weighing before you spend five thousand pounds.

Half a new building, and it is the half nobody sees.

Stand in front of a garage and what you actually look at is the walls and the door. The roof is the part you have just paid the most to replace and the part least visible from the house or the street. If the panels are forty or fifty years old — and on a concrete garage of that age they are often crumbling or breaking up at the edges — the building will look much as it did before, only with a tidier roofline.

The windows and personnel door are usually the same vintage as the panels, so they tend to want replacing too, which adds cost that was not in the original plan.

It would be dishonest to pretend the right-hand column is always cheaper. Usually it costs somewhat more — and that is exactly the point of putting them side by side. The question worth asking is not which number is smaller, but what the difference actually buys: a complete building instead of a new roof on old walls, one company responsible for all of it instead of three quoting separately, and a guarantee that means something if anything goes wrong.

Sometimes it genuinely is less. That happens often enough to be worth checking before you commit to either.

In short: replacing a garage roof typically costs between £4,500 and £6,500 once removing the old door, fitting a new one, taking off an asbestos roof, re-trussing and new sheets are counted, plus access equipment such as a trestle system. It costs more than people expect for a structural reason — the walls have to stay standing while the roof comes off, which makes the building unstable during the work and forces every step to be worked around the old panels, where demolishing the whole garage would be simpler. Asbestos cement roofs, common on garages built before the UK ban in November 1999, must be removed and disposed of under licence with consignment notes, and cannot go in a skip. The job usually needs three separate trades: a builder or joiner, a licensed asbestos contractor and a garage door company. Felt coverings last about four or five years. Afterwards you still own a forty or fifty-year-old building whose visible parts — the walls and the door — are unchanged, often with windows and a personnel door of the same age still to do, and no meaningful guarantee, because new work joined to old panels leaves nobody clearly responsible for a later leak. Nucrete does not replace roofs or carry out refurbishment; it manufactures and installs new buildings, removes old ones including licensed asbestos removal from around £1,100, and lays concrete bases, with a 10-year structural guarantee on the building it supplies.