The short answer
A new roof can leak for a handful of reasons: a flashing that was never finished, a tile or slate left loose, a gap at the ridge or verge, or condensation that only looks like a leak. Work out where the water appears, photograph it with the date, and tell the roofer in writing. Section 49 of the Consumer Rights Act 2015 expects reasonable care and skill.
Water coming through a roof you have only just paid for is upsetting, and it is usually traceable to one small detail rather than the whole roof.
Where fresh roofs let the water in
New coverings are rarely the problem. Slates and tiles shed water well when they are laid to the right lap. Leaks on a recent job tend to start where the roof meets something else, because those joints are fiddly and are finished last.
Which joints should you look at first?
Start at the flashing, the lead or metal seal where the roof meets a wall, chimney or roof window. If it was dressed down badly, or the mortar joint it sits in was never pointed, water runs behind it. Next come the valleys, the sunken channels that collect rain where two slopes join. A valley liner that overlaps by too little will pass water in heavy rain and look perfectly dry the rest of the time.
The ridge along the apex and the verge, the roof edge that runs up a gable end, are the other usual suspects. A ridge tile that is not fully bedded or fixed leaves a slot for wind-driven rain. A soil vent pipe or a flue passing through the slope needs its own collar or soaker, a small folded sheet of lead worked into the courses around it.
A single loose tile or a slate nicked during fitting can also let water onto the underlay, the waterproof sheet beneath the tiles, and that water can travel several feet before it drips from a ceiling. Where the stain shows is rarely where the hole is.
Is it a leak or is it condensation?
After a re-roof, a loft that was always damp sometimes starts to show it. A new roof is tighter than the one it replaced, and moist air from kitchens and bathrooms has less chance to leak away through gaps in the old covering. When that air meets cold timber or the underside of the underlay, it turns to water and drips.
How can you tell the difference?
Condensation tends to show up on cold mornings and after showers or cooking, not only in rain. It often appears on the underside of the underlay and on nail tips, and it leaves the roof timbers dark across a wide area rather than at one point. A true leak follows the weather, is worst when rain is driven by wind, and traces back to a single spot such as a flashing or a cracked tile.
Ventilation decides which one you have. BS 5250 deals with moisture in buildings. Marley's cold roof guidance, where the underlay is HR and so non-breathable, asks for 25mm of eaves ventilation when the pitch is 15 degrees or less and 10mm above that. If the eaves were blocked by insulation pushed too far, or vents were left out, the damp can be mistaken for a fault in the covering.
What the law expects of the roofer
When a tradesperson works for a consumer, section 49 of the Consumer Rights Act 2015 expects the roofer to show reasonable care and skill. A roof that lets water in soon after the job is a fair reason to ask that the roofer come back and look.
Do you have to pay while the leak is unresolved?
That depends on your contract and on what a proper inspection finds, so it is worth putting the question to the roofer in writing rather than refusing payment on the doorstep. Keep your contract, the invoice and any messages about the job together in one place. If the firm will not answer, Citizens Advice runs a consumer helpline on 0808 223 1133, and a trader is obliged by law to tell an unhappy customer about any dispute scheme that is available.
Do not let a second roofer rip out the first one's work before the original firm has seen it, unless water is actively coming in and the house is at risk. If it is, a make-safe repair is reasonable, and photographs of what was found before and after it protect you.
Raising it in writing
A short email, followed by a letter if nothing happens, is the best record you can have. It should be calm and specific, because a vague complaint is easy to put off.
What should the message say?
Give the date the job was finished, when you first noticed water, and which room it appeared in. Say whether it rained hard, whether the wind was strong, and whether the stain has grown. Attach dated photographs of the ceiling, the loft seen from the hatch, and the roof from the ground. Ask for an inspection date, and set a sensible deadline for a reply.
Keep temporary measures simple: a bucket, a towel and a plastic sheet inside to protect furniture, nothing that means climbing onto a wet slope. If water is close to wiring, turn that lighting circuit off at the fuse board and get an electrician in before anything else. Our answer on leaks near a light fitting covers it.
If the leak is not from your roofer's work, or you want a second set of eyes, our guide to finding the source of a roof leak explains the process. Send the photos over and we will arrange a survey, showing you what is on your roof and quoting one total in writing. Our emergency roof repairs page has the detail.
Questions about a leaking new roof
Is a drip in the first heavy rain after a re-roof normal?
No. A new covering should keep the weather out from the first storm. A drip is a sign something needs finding, whether it is a flashing, a loose tile or condensation. Photograph it, note the date, and ask the roofer to inspect before you let anyone else touch the area.
Can I get another roofer to look before my own roofer returns?
Yes, for a survey and photographs. Tell your original roofer first and give them a fair chance to come back. If water is coming in and damage is growing, a make-safe repair is sensible; keep the old materials and photographs of what was found so the question of who is responsible stays clear.
The full picture: Emergency and general roof repairs in Taunton ยท More short answers