The short answer
There is no fixed number of roofers for a roof replacement. A small roof may be done by a small gang, and a large or complicated one needs more hands working on different slopes or tasks. The number of people mostly changes how many days the job takes, not how well it is done. What matters is who leads the work, who checks it, and who is on your roof each day.
The roles on a roof replacement, why more people usually means fewer days rather than better work, and what to ask a roofer about their crew.
Who does what on a re-roof
A roof replacement is several trades in a row, and a gang usually splits by task. The scaffolders put up the access and take it down, and they are often a separate firm from the roofers. On the roof, the stripping crew takes off the old tiles or slates and passes them down, and sorts what can be reused from what goes to waste.
Next are the people who lay the new roof: someone fitting the underlay (the waterproof sheet under the covering), someone nailing the battens (the narrow laths each row of tiles is hooked over), and the tilers or slaters who fix the covering row by row from the eaves up. A roofer who does the detail work, the ridge capping the top, the verges finishing the gable edges and the flashings sealing joins against a wall or stack, is usually the most experienced person on site.
At ground level one person feeds materials up, loads the skip and keeps the drive and garden clear. In practice one person often does several of these jobs in a day. What you want is a clear lead who answers for the whole job, not a name on the quote and a different face every morning.
Does a bigger gang finish faster
Up to a point, yes. Two slopes can be stripped and relaid at once by two groups, and a larger roof gains from extra hands because there is more to do at the same time. A small terraced roof does not gain much, because there is only so much surface one person can work on safely without getting in another's way.
More people also cost more for each working day. Checkatrade's June 2026 roofing guide gives a typical range of £280 to £360 per day for a roofer, so the price of a job depends on the people multiplied by the days. The labour in a price comes from the hours the roof needs, however those hours are split between people and days.
What a larger crew does change is how long the roof is stripped and how long you have people on site. If the weather is changing, a bigger gang can finish a slope before the rain; if you are working from home, fewer days may suit you better. Our answer on how long a roof replacement takes goes through what sets the days.
Why the number is not a measure of quality
Quality comes from how the work is planned, set out and checked, not from headcount. A crew of any size can lay tiles on battens that are not straight, skip a fixing or leave a flashing loose. A crew of any size can also do the work properly if somebody checks the gauge of the battens, the fixings at the ridge and verge and the lap of the underlay before each stage is covered up.
That checking is what to look for. Ask who is on site each day and who signs the work off. Ask whether the person leading the job is on the roof or only visits. Ask what is checked before the covering goes on top of the underlay, because after that nobody can see it. We share photos of your roof from the survey and at the key stages, so the work behind the finished tiles is on record.
On fixing, BS 5534 is the standard to ask about, and your roofer should be able to say how yours follows it. It is guidance, not law, but a roofer who knows it will answer the question easily.
Questions to ask about the crew
Before you agree, find out which named people will be working up there and whether they are the roofer's own people or sub-contracted for the job. Ask which firm puts up the scaffold, and who deals with the council if it has to go up over the pavement. That is a matter for the highway authority and its licence, and we line it up with the scaffolder so you are not chasing paperwork.
Ask how the work is supervised, who you ring if something looks wrong, and how you are told about changes such as rotten timber found once the tiles are off. A written total price with the survey photos behind it should show that someone really inspected the roof, and any extra found on site should come back to you as a written price before it is done.
Citizens Advice also recommends asking a trader for recent examples, getting in touch with those customers, and taking care with anyone whose only contact is a mobile number. Our guide to comparing roof replacement quotes helps with the rest, and the roof replacement page explains each step we take, starting at the survey and ending at the final walk-round.
More on this in Roof Replacement & New Roofs in Crawley
Two crew questions
Is it a problem if the same roofers do not turn up every day?
Not by itself, if one lead person stays with the job and knows what was done the day before. What causes trouble is a job with nobody in charge. Ask who leads your roof, how work is handed over between days, and who you should call if you spot something you are unsure about from the ground.
Should I be on site while the roofers work?
You do not have to be there all day, but being reachable matters. Rotten timber or an awkward junction found under the old covering needs a decision, and a written price for any extra, before the new covering goes over it. Agree at the start how you will be contacted and what photos you will be sent.