The short answer
Three written quotes is the usual advice. Citizens Advice recommends collecting written prices from at least 3 different traders before you decide. Three gives you enough to see what is normal for the job without turning the search into a project. What matters more than the number is that each quote describes the same work, so you are comparing like with like.
Why three is the number most advice settles on, how to make the quotes comparable, and what to do when two of them disagree.
Why three, and not one or ten
One quote tells you what one firm wants to charge, and nothing about whether it is high, low or sensible. Two can leave you stuck if they differ, with nothing to break the tie. Three starts to show a pattern: two close together and one far out usually marks the odd one, and asking why is worthwhile.
More than three rarely helps. Each extra roofer means another morning off work for you, another opinion and a longer wait while the weather turns. Past four or five, the search tends to leave you more confused than when you began.
The advice is worth keeping as written: written quotes, at least 3, from different traders. Written means something you can look at again and hold the firm to. Different means not three names from the same company. For a very small repair, such as one slipped tile, you may sensibly get fewer, since the effort outweighs the difference. For a new roof, take the time.
Our wider answer on how to tell a dodgy roofer is useful reading before any of them visit. Write down your questions in advance, so each firm answers the same ones and you can compare the replies afterwards.
Make sure each roofer prices the same job
The biggest mistake is comparing totals when the jobs are not the same. Before the first visit, decide what you want: repair or replace, which slopes, which covering, and whether the chimney and the gutters are included. Tell every roofer the same thing, and ask each to confirm the scope in writing.
Then ask the same handful of questions of every quote. What is the covering and how much of the roof does it reach? What happens to the battens and the underlay? Does the price include scaffolding, and does it include VAT? What happens to the old materials and the waste? What guarantee is offered, and for how long?
A single total price in writing is clear and fair. What you need alongside it is a description of the work that lets you see whether two totals cover the same job. If one firm quotes for a full strip and another for patching, the lower figure is not a better deal. A good roofer also shows you what the survey found, with photos, so the scope rests on your roof and not on a guess.
What to do when the numbers disagree
When one quote is far below the others, read it again. Does it leave out scaffold, VAT or waste removal? Is it for a thinner covering, or a repair where the others propose a replacement? A low price for less work is not a saving, and a quote that will not say what it includes is a warning in itself.
When one is far above, ask why. Sometimes the roofer has seen something the others missed, such as rotten battens, a poor chimney or a failed valley. Ask to see the photos. If the answer is pressure to sign today, walk away. A genuine price will still stand next week.
For a rough guide to what is normal, our roof work costs guide collects dated national ranges,. These are yardsticks only, and the price for your roof depends on its size, covering, access and condition.
Do not choose on price alone. Ask yourself who explained the job best, who answered questions plainly and who gave you something in writing you could rely on.
Checks before you sign
Quotes are only the start. Before you sign, ask for recent examples of similar work and, where you can, speak to those customers. Citizens Advice cautions that a written reference can be faked, and that a trader giving only a mobile number deserves suspicion. When a firm quotes a trade body or scheme as proof of standards, find that body's published member list and check the firm appears on it. Make sure you and the trader are both insured, and ask to see the paperwork rather than taking it on trust.
If you sign at home after a survey, you usually have a right to cancel within 14 days, and the firm should tell you so in writing. Our page on how to complain about a roofer covers what to do if things go wrong later.
Our own way of working is simple: a survey first, photos of your roof shared with you, then one written total price. If you are collecting quotes now, you can read how that goes on our home page. Sending pictures of the slopes with a short description of the problem is enough to begin, and it gives us a clear idea of what to look at on the day.
More on this in Roofers in Crawley: the full guide
Two more quote questions
Should I tell each roofer what the others quoted?
No. Share the job description, not the competing prices. A quote built to beat a rival figure tends to cut the scope quietly rather than the margin. Ask each roofer for their own price for the same described work, then compare the written totals and what each one includes.
Do roofing quotes cost money?
Some firms charge a call-out fee for a visit, others give a quote after a free look, so ask before they come. For a planned job, agree in advance whether the survey is free and what the fee, if any, is set against, and get that confirmed in writing.