The short answer
If it rains, work on the exposed part of the roof stops and that area is covered. A properly run re-roof opens only as much roof as can be made watertight the same day, using underlay and heavy-duty sheeting held down with battens. The house should stay dry. Light showers may be worked through on parts already felted, but heavy rain, high wind or a bad forecast halts the strip until it clears.
The plan that comes before the weather
Rain is not a surprise on a British roof job. The sensible way to deal with it is to expect it. The crew checks the forecast for several days ahead and again each morning, and decides how much of the roof to open. A slope may be stripped and felted in a morning, so the open area is small at any moment. If the forecast turns, the stripping is held back until it passes. A roofer who strips a whole house and hopes is not planning properly.
Material is staged for the same reason. Sheeting, battens to hold it and spare underlay are on site before the first tile comes off, so cover can go on in minutes rather than after a phone call. Ask whether this is the arrangement before you accept a quote, because it is the single biggest protection against a wet house.
What covers the roof
Once the old covering and battens are off a section, the rafters are exposed. The first layer to go on is the new underlay, a sheet that lies across the rafters and sheds water while the roof is open. Underlay is a second line of defence in the finished roof, and during the job it serves as temporary cover, but only for a limited time, because each product has its own exposure limit stated by the maker. Do not treat it as a permanent roof.
Where rain is more serious or the underlay is not yet down, heavy-duty tarpaulin or sheeting goes over the area, tied or battened at the edges and weighted so wind cannot lift it. It runs over the ridge so water cannot get in at the top. A roof valley or an open hip needs careful sheeting because water collects there. The aim is to keep the rafters and the loft insulation dry, since wet insulation loses much of its value and a wet ceiling can take weeks to dry out.
When work carries on and when it stops
A light shower on an area that is already battened and felted does not usually stop the tiling, though tiles are slippery when wet and safety comes first. Heavy rain, thunderstorms and gusty wind end the day's work. Wind is as important as rain, as a half-stripped roof catches the wind like a sail, and loose tiles and sheeting can become projectiles. If the weather stops work, the roof is secured and the crew goes home. See the page on replacing a roof in winter for how colder months change the programme.
The effect on the schedule is real. A wet week can delay the job by several days, and a competent firm tells you that. It is also normal for the programme to run longer than the quote's working-day count in unsettled weather.
What to check indoors
During the work, look at the ceilings and the loft after any rain. A damp patch that is spreading, a drip in the loft or a stain on a top-floor ceiling should be reported to the roofer at once, not at the end of the week. Most leaks during a job come from a corner of the sheeting that lifted, or from a flashing area left open overnight, and they are easy to fix when found early.
Photograph any damp area with the date, and mention existing stains beforehand, so there is no argument about what is new. If a leak damages the ceiling or contents, that is a matter between you and the contractor, and your own buildings or contents insurer. A written quote should say who is responsible for weather damage during the works.
The loft and what is stored there
Even with good cover, moisture can find its way to the loft floor in a downpour, so anything stored there should sit on a raised shelf or in sealed boxes. Cardboard boxes of photographs and papers are the usual casualties. Insulation that gets wet should be lifted and dried or replaced, not simply covered over, because damp insulation holds moisture against the ceiling for weeks. A quick look with a torch at the end of a wet day takes two minutes.
Roofs that cannot be done in rain
Some work cannot go ahead in the wet at all. Flat roof coverings such as GRP and torch-on felt need a dry, warm deck to bond properly, and a liquid or adhesive system on a damp surface will fail later. A roofer who lays them in the rain is borrowing against your future. Lead flashing work and mortar pointing wait for the weather to improve as well. For the timing of the first and last stages of a job, see what stripping a roof involves.
Our approach is simple: we open only what we can close, we keep sheeting on site, and we tell you plainly when the weather has cost us a day. The quote is a fixed figure, and the process is described under roof replacement.
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