What happens when a roofer comes to look at a repair?

The visit starts with you. Where is the stain, and when did you first see it? Does it show after every shower or only when the wind is in one direction? Has anyone worked on the roof before, and is there a guarantee or paperwork from that job? A leak that appears in a particular kind of weather gives the roofer a head start, because it narrows the search to a face of the roof or a single junction.

Tell the roofer about anything unusual. A new satellite dish, a recent loft conversion, a neighbour's building work or a gale that brought down a branch can all explain a fault. If a storm caused the damage, you should tell your insurer before arranging repairs, as Which? advises, and keep your photographs and receipts safe for emergency work. Our answer on whether to call a roofer or your insurer first covers the order.

This chat also settles access. The roofer needs to know where a ladder can stand, whether a neighbour's drive is the only route to the back.

Much of a roof can be read from the garden. Binoculars or a long lens show slipped tiles, a sagging ridge line, cracked mortar at a chimney and gutters that are full of moss. The roofer then goes up to the points that need a close view, using a ladder, a tower or, on a tall building, a scaffold when the job calls for one.

Close up, the checks follow the weak points. The ridge and hip tiles are looked at for fixings and for gaps. Verges, where the tiles finish at an end wall, are checked for loose tiles. Flashings, the strips of lead that seal against chimneys and walls, are inspected for lifted edges. Valleys, the gutters formed where two slopes join, are checked for splits and blockage. Our answer on roof repair photographs shows how the pictures are used.

On a fragile roof, such as asbestos cement sheets, the roofer does not walk on it and checks from a tower.

Looking from below shows what the top surface hides. In the loft the roofer checks the underlay, the layer laid under the tiles, for tears and wet patches, and at the timbers for staining, rot and light showing through where it should not. A damp rafter that is dry on the surface points to a slow leak, and a dark ring on the felt shows exactly where water has been collecting.

A moisture meter helps to tell an old stain from a live one. A brown mark that is dry may be from a fault already fixed. A damp one that is still growing means the leak is active. Condensation can look the same, so the roofer checks insulation, ventilation and whether the stain shows only in cold weather.

On flat roofs, or where there is no loft, the survey works from the ceilings below and from the roof surface itself. If a leak travels along a beam before it drips, the wet spot inside may be some distance from the hole outside, and the roofer follows the water back to its source.

After the checks comes the answer that matters most. A repair is a lasting fix to a specific fault. A patch is a short-term measure that stops water while a larger decision is made. Replacement is for a roof that is past repair, where fixing one fault will only reveal the next. Our advice is just enough work to cure the fault fully, and a repair stays a repair when it will hold.

You see the evidence behind the verdict. Photographs of each fault are sent with the quote, so you can look at the slipped tile, the failed flashing or the stained felt on your own screen and compare it with what we say. If you want to ask another roofer, you have the pictures to show them.

If the visit finds something outside the repair, such as rotten timbers or a chimney that is crumbling, we point it out plainly, with a photograph, and leave that decision to you. Our answer on the signs a roof needs repairing lists what to watch between visits.

The quote follows the visit as a written document with one overall price for the work described. Check that it says what is being done, which parts of the roof, and whether VAT and any scaffolding are included. A quote that is vague about those points is hard to compare with another.

If the work is notifiable under the Building Regulations, we file the notification and explain what it involves. A simple like-for-like repair usually is not, but the Planning Portal says approval can apply once a job passes certain limits, and we tell you where yours falls.

Consumer law matters here too. If you sign at home, the Consumer Contracts Regulations 2013 treat it as an off-premises contract with a 14-day cancellation period. Work begins within it only on your written request. Regulation 28 treats a visit you ask for to deal with an urgent repair differently, so making a leak safe is not held up.

The roof repairs page has the full range of jobs a survey can lead to.