Start with the job
Roofers do not all take on the same work. Some only repair, some mostly fit flat roofs, and a few handle leadwork or chimneys as a speciality. Each listing here ticks the services the business names on its own website, so check that your job is ticked before you ring. Where a listing reads "no information yet", the website did not say, and a phone call settles it.
What the rules ask for
In England, re-covering a roof normally needs Building Regulations approval, and the insulation is usually improved at the same time. A roofer registered with CompetentRoofer or NAPIT can certify a roof replacement themselves. Otherwise the work goes through your council's building control service, and each county page here names the councils that cover its towns. Ask which route your roofer uses, and keep the certificate, because a buyer's solicitor or lender may ask for it when you sell.
Planning permission is a separate matter. In England, re-roofing a house in a way that does not change how it looks will usually not need it, and roof windows are usually allowed within set limits. Flats are treated differently, and Scotland, Wales and Northern Ireland have their own rules.
Scaffolding and safety
The Health and Safety Executive treats all work on roofs as highly dangerous, even a job that takes a few minutes, and says sloping roofs need scaffolding to stop people and materials falling from the edge. A quote for work on a pitched roof should say how the roofer will get up there. If the scaffold has to stand on the pavement, the scaffolding company needs a licence from the council first.
Bats and old cement roofs
Bats and their roosts are protected by law, and repairing or replacing a roof is one of the jobs that can disturb them. If you think bats use your roof, the National Bat Helpline gives free advice before work starts. Old cement sheet roofs on garages and outbuildings can contain asbestos. Ask how the roofer will handle and dispose of the sheets.
Reading a rating
Every listing shows the Google rating beside the number of reviews behind it. Read the two together. A perfect score from three reviews tells you less than a slightly lower score from a hundred.
What to ask on the first call
Ask for a written quote that lists the work, the materials and the access. Ask to see the public liability insurance certificate. Ask what the guarantee covers, how long it runs and whether an insurer backs it if the firm stops trading. Ask who will be on the roof, and who deals with building control. Get the answers in writing before you agree to anything.