The short answer
Partly. In the rain a roofer can make a leak safe: fit a tarpaulin or temporary cover, clear a spilling gutter, reseat a slipped tile and relieve water trapped in a ceiling. Anything that depends on a bond or a cure has to wait for dry weather, such as mortar, flaunching, adhesive, sealant and flat roof membranes. A make-safe now, then the proper repair once the roof has dried, is the usual order.
What a roofer can do while water is coming in, what needs a dry spell, and how the two visits fit together.
What can be done while it is raining
Rain does not stop every roof job, and when water is coming in, waiting for sunshine is rarely the right call. The first aim is to stop the damage spreading. That can mean fixing a tarpaulin over the damaged area and battening it down, putting a temporary cover over a gap where tiles have gone, clearing a gutter that is spilling water behind the fascia, or lifting a slipped tile back into place so it stops funnelling water inwards.
Inside the house, the work is just as practical. Buckets go under drips, furniture and rugs are moved, and a ceiling holding a pool of water above it can have a small hole eased through at the lowest point, so the water runs into a bucket in a controlled way rather than bringing the whole ceiling down.
None of this is the finished repair. A make-safe buys time and limits the harm to insulation, plaster and wiring. It also gives the roofer a clear picture of what has failed. Our page on what a roof make-safe involves sets out the steps, and the wider emergency and general roof repairs page shows the other urgent jobs we take on.
What has to wait for dry weather
Many roof materials need a dry surface to bond, and some need hours or days to cure. Sand and cement mortar for ridge tiles, hip tiles and flaunching around a chimney pot will wash out or fail to grip if it is laid in the wet. Adhesives and sealants will not stick to a damp surface, and a bead of sealant laid over a wet joint can seal moisture in rather than keep it out. Our page on whether roof leak sealants work goes into that trap.
Flat roofs are fussier still. A felt, EPDM or GRP patch needs a clean, dry deck, and torch-on felt involves a naked flame that has no place near a soaked roof. Resin for GRP will not cure properly in damp air. Lead work needs a dry substrate so the roofer can see what is underneath and fix the sheet where it should sit.
If a repair is forced through in the wet, it often lets go within weeks and the leak returns, sometimes in a new place. That is why we separate stopping the water from curing the fault.
Is it safe for a roofer to go up in the rain?
This is a judgement call, and a good roofer will make it on the day. Wet tiles, slates and metal are slippery, moss on a pitched slope acts like grease, and the foot of a ladder can sink into soft lawn. Wind adds to the danger because a tarpaulin in a gust can pull a person off balance. Lightning is a clear reason to stay on the ground. If conditions make it unsafe, the sensible step is to wait for a break in the weather rather than take a risk for the sake of speed.
For you, the rule is simple: do not go up there yourself. Trying to cover a leak from a ladder in the dark and the wet is a fall waiting to happen. Water can be managed from inside with buckets and towels, and a roofer can reach the outside with the right access, such as a tower or scaffold when the height calls for it.
If water is running towards wiring or a ceiling light, switch that circuit off at the consumer unit and keep clear of the room until it has been checked.
What happens once the rain stops
After a make-safe, the roof needs a proper look in dry conditions. We survey the area, check the battens, underlay and flashings around the spot where the water came in, and send you pictures of the fault itself. Often the cause is not where the stain appears on the ceiling, because water runs along rafters and felt before it drops, so tracing it takes patience. The page on finding where a roof is leaking explains how that detective work goes.
Once the survey is done, the lasting repair is priced as a written total that says plainly whether a return visit with materials or access equipment is needed. Some faults are quick to put right once the roof is dry. Others, such as failed felt or rotten battens, take longer, and we tell you that before work starts.
The temporary cover then comes off at the end of the repair, and the area is left tidy. Keep any pictures you took of the damage and the receipt for the cover, because both are useful if the loss ever goes to your insurer.
More on this in Emergency & General Roof Repairs in Crawley
Two more questions about wet-weather repairs
Can I leave a tarpaulin on all winter?
Think of a tarpaulin as a stopgap and never as a roof. Left in place for a long spell, it flaps against the tiles, rubs through its fixings and traps damp air underneath, so the problem can get worse unseen. Treat it as cover for the days between the leak and the proper repair, and have the cause put right as soon as the weather allows.
Will a repair done in the rain be guaranteed to hold?
A wet-weather job is meant to hold water back, not to be the permanent fix, and nobody can promise it will last through a storm. A good roofer says clearly which parts are temporary and which are not. Ask what has been done, what it protects against, and when the lasting repair will be priced and booked.