What happens if it rains during a roof replacement?

1Why only part of the roof is open at once

A replacement is not a roof lifted off and left bare. The crew strips one section at a time, usually along a single slope or bay, and the exposed timber is covered again before they move on. Underlay and battens follow close behind the stripping, so the area open at any moment is small enough to be sheeted quickly if the sky darkens.

Sequence counts for more than speed. A big gap in the roof is a gamble with the weather, whereas a small one can be shut in minutes. On a tall house with a long slope, or a roof with awkward valleys, the sections are smaller still. When you ask a roofer how they cope with rain, this is the answer to listen for.

It also helps to have enough people on site, and enough sheeting. A crew spread too thin cannot cover a slope fast, and the plan should name who does what when the first drops fall.

2Temporary weathering and night-time cover

When work stops for the day, every open slope is covered with heavy-duty sheeting or tarpaulin, battened down along the full edge so wind cannot get underneath. The sheet is taken over the ridge rather than just laid on the slope, and held down with timber, not loose weights. Gutters and downpipes are checked as well, so run-off goes where it should and does not pour into open eaves.

The same applies at lunchtime and whenever rain is forecast during the day. The crew would rather sheet early and lose an hour than watch a ceiling take on water, and a good foreman makes that call without being asked. A flat roof is treated differently, because a waterproof membrane needs a dry deck to bond to. Flat roof stages are planned for settled spells, and every open edge is covered at close of work, the same discipline applied to a different covering.

3When the work stops

Some weather simply ends the working day. Heavy, sustained rain makes wet slopes unsafe to work on and risks soaking the timbers. High wind makes large sheets dangerous to handle and can lift temporary cover, so stripping does not start when a gale is forecast. Lightning is a clear stop. If the roof has just been opened that day, it is sheeted down and the crew leaves.

Delays of this kind are normal on the Sussex coast, where weather can change within hours. A job estimated at a certain number of working days will run longer in a wet week, and you should expect that. It is a reason to ask your roofer how many dry days the job needs and what happens to the schedule if the forecast changes. A sensible answer mentions spare days and a clear rule about when to stop. Our page on checking a re-roof quote lists questions worth putting to any contractor, including how rain is handled.

4What you can do inside the house

A few simple steps from you help a lot. Clear the loft of anything that dust, debris or damp would spoil, or cover it with sheets. Move furniture away from the ceilings below the roof while it is open. Look at the ceilings the morning after any heavy rain, and tell the crew at once if you notice a mark, however small.

Keep a bucket and some old towels handy until the underlay and battens are complete on every slope, and photograph any stain you find so the crew can see exactly where to look. If a loft room is planned, re-roofing before a loft conversion explains why the sequence of the two jobs is important, since a leak above finished rooms is far worse than one above an empty loft. Pets and young children are best kept away from the rooms directly beneath the work, as noise and falling dust can be alarming on the first day.

5Tiles, metal and other coverings in wet weather

Weather plans differ with the covering. Tile and slate roofs are stripped in sections and re-laid behind the underlay, so they follow the pattern above. A metal roof goes down in long sheets and needs dry conditions for fixing and sealing the seams. A stone-slate roof, or a roof on a listed building, calls for even more careful sequencing.

Whatever the covering, the visit before the quote is where this gets settled. We study the slopes, the access and where rain would do most harm, then send you photographs of what we saw. The quote then arrives in writing as one total. It should say how the roof will be protected, because that is the part of the plan you rely on when it rains. For the whole service, see our roof replacement page.