The short answer
To check a roofer is legitimate, confirm the firm exists on the Companies House register or as a named sole trader, find a real address and a landline, look at finished work you can visit, get the quote in writing, ask to see insurance documents, and be wary of any deposit that is large or urgent. A genuine firm will answer all of that without fuss.
Does the firm exist where it says it does?
Start with the name on the van, the leaflet or the website. If it trades as a limited company, search that exact name on the Companies House register. The entry shows the registered office, the date the company was formed and who the directors are. A company incorporated last month is not automatically a problem, but it tells you not to take a claim of long experience on trust. Look for the same name on the quote and any invoice, because a firm that trades under one name and invoices under another needs explaining.
Sole traders are not on that register, so the checks lean on the other items in this list. You are looking for consistency: one name, one address, one phone number, repeated everywhere. Gaps are where trouble starts.
If a company number appears on the quote, check it is real and that the name matches. If the firm is registered for VAT, the number should be on the paperwork too, and our note on VAT on roof repairs and new roofs explains what to expect on a quote.
A real address, a landline and a face you can meet
A mobile number alone is common and not a fault in itself, but a firm that has only a mobile and a web form gives you nothing to fall back on if work goes wrong. Ask for a business address and a landline as well. Then test them. Look the address up on a map. A unit on a trading estate or a house in a Stroud valley village is fine; a mail-forwarding box or an address that turns out to be a car park is not.
Ring the landline at a normal hour and see who answers. Ask who will actually be on your roof and whether the person quoting is the person doing the work. A firm using subcontractors is not doing anything wrong, as plenty of good ones do, but you should be told who is responsible for the job and who you can phone about it afterwards.
A genuine firm is comfortable being asked these things. Irritation, or an answer that shifts each time you ask, tells you what you need to know.
Work you can go and look at
Photographs on a website can come from anywhere. Ask for the address, or at least the street, of a roof the firm has finished in the last year or two, and ask if the owner is happy to be asked. You do not need a long list. One or two recent jobs on roofs similar to yours is more useful than a gallery.
When you see a finished roof from the pavement, look at the straight lines first. Courses should run level, ridge tiles should sit evenly, and the lead at a chimney should lie flat without gaps or smears of mastic. If the job was a repair, ask the owner whether the roof was tidied and the waste taken away. If the roof was stone or slate, check the firm re-used or matched the covering rather than putting something cheaper on top, because like for like matters on older homes in a conservation area.
Be wary of anyone who offers only pictures, only a social media page, or a list of names they cannot connect to an address.
The quote, the insurance papers and the guarantee
A written quote is the plainest test there is. It should name the firm, give the address of the job, describe the work, list the materials by name and show the price with VAT stated. A figure scribbled on the back of a card is not a quote. If the work involves scaffold, a strip of the old covering, new underlay, battens and waste removal, you should expect the quote to say so. If you want a yardstick for what that looks like, our page on what a roofing quote should include goes through what to look for.
Ask to see insurance documents, not just hear that they exist. A certificate carries the insurer's name, a policy number, the dates it runs and what it covers. Read the dates. Ask the firm to send a copy, and phone the insurer if anything looks odd. Public liability cover protects your property if something is damaged, which matters when someone is working at height above your home.
Finally, ask what guarantee comes with the work, who gives it, and whether it is on paper. A guarantee is only as good as the person standing behind it, and a promise made in your driveway is hard to enforce a year later.
How a genuine firm handles a deposit
Be cautious about any request to pay a large sum before work starts, and doubly so when the request comes with pressure: a price that is only good today, a cash discount, or a story about materials that must be bought this afternoon. A firm with a proper business behind it can usually buy materials on account or ask only for what has been ordered specially.
If a deposit is reasonable, it should be tied to something you can see, such as a named product ordered for your roof or a scaffold booked, and written on the quote with the balance due at stated stages. Pay by a traceable method rather than cash and keep the receipt. Our guide to whether a roofer should ask for a deposit up front sets out when that is fair.
The same caution applies to any caller who knocks at your door unprompted; the signs are different and are covered in spotting doorstep roofers and saying no. For the wider process of comparing firms, such as what to ask and what to compare, see how to choose a roofer in Stroud.
If you would like a firm that publishes typical costs before a visit and puts a written quote in writing after the survey, you can start at Supreme Roofing Stroud, and the 10-year workmanship guarantee comes in writing too.