London roofs leak in their own ways. Many terraces hide their roof behind a parapet, flats share one roof between several owners, and almost every house has a flat roof somewhere at the back. This guide from LRC Group Roofing & Building Ltd explains what to do when water comes in, where it is most likely to be getting in, and how to get it repaired.
If water is coming in now, call 020 8049 1949 or 0777 764 6199 and tell us it is urgent.
Before Anything Else
- Isolate the electrics. If water is near a light fitting, socket or switch, turn that circuit off at the consumer unit and keep it off until it has been checked.
- Stay clear of a sagging ceiling. Plaster that bulges or cracks may be holding a lot of water and can give way suddenly.
- Contain the water. Buckets under the drips, towels along the skirting, and furniture, rugs and electrical items moved out of the way.
- Do not go onto the roof. Parapets, valleys and flat roofs high above the street are no place to be in wet or windy weather.
- In a flat, tell the neighbours. Water travels between floors, so the flat above or below may be affected too.
Hidden Roofs Behind a Parapet
Walk down most Victorian streets in Battersea, Clapham, Fulham, Putney or Wandsworth and the roofs are hard to see. Many of these houses have a V shaped roof tucked behind the front wall, with both slopes draining into one gutter that runs front to back down the middle of the house. The water leaves through an outlet and hopper at the rear.
Because nobody can see that gutter from the street, it tends to be forgotten until it overflows. Leaves, moss or a split in the lining is enough to back the water up, and it then comes through the top floor ceiling, often in the middle of a room rather than near a wall. Clearing the outlet sometimes solves it; a lining that has split needs relining. Our chimneys and leadwork page covers valley and gutter linings.
Flat Roofs, Back Additions and Dormers
Kitchen extensions, back additions, dormers and the roofs of mansion blocks are usually flat. Water that sits on them for days finds any tired seam, and it can travel some distance under the covering before it shows inside, so the drip is rarely directly below the fault. We repair splits, blisters and worn joints and can advise when a covering has reached the end of its life. See flat roofing.
Chimneys, Party Walls and Parapets
On a terrace, chimney stacks often sit on the party wall and are shared with next door. Lead flashing that has lifted, cracked mortar and worn copings on top of parapet walls all let water into the brickwork, where it shows as damp on a chimney breast or high on a wall. See chimneys and leadwork and brick repointing.
Flats and Shared Roofs
If you own a flat in a converted house or a block, the roof is usually not yours alone. In most cases it belongs to the freeholder, or to all the owners together, and the lease says who arranges and pays for repairs. Report the leak to the managing agent or freeholder in writing, with photos, and keep a note of the dates.
We inspect the roof, find the cause and quote for the repair, so whoever is responsible has what they need to approve the work.
Is It Definitely the Roof?
Some damp that looks like a roof leak is something else. Condensation forms in cold lofts and under flat roofs when warm, moist air from the house meets a cold surface, and it is worst on cold, still mornings. A leaking bath, shower tray or pipe on the floor above can also mark a ceiling.
A good rule of thumb: if the stain grows during or just after rain, the roof or a gutter is the likely cause. If it appears in dry weather, look at plumbing and ventilation first.
What to Tell Us
- The address, and whether it is a house, a flat or a block
- Which room the water is showing in, and which floor
- Whether the roof is pitched, flat or hidden behind a parapet, if you know
- When it started, and whether it leaks in all rain or only in strong wind
- Any photos of the stain or of anything you can see from the street or the garden
Our team inspect the roof to find the cause before carrying out the repair, and quotes are free. Some repairs need scaffolding, and scaffolding on a public pavement needs a council licence, so access can affect the timing of a permanent repair. More detail is on our roof repairs page.
Roof Leak Questions
Why is water coming through the ceiling in the middle of the top floor?
On a terrace with a hidden V shaped roof, rain drains to a gutter that runs down the middle of the house between the two slopes. If that gutter or its outlet at the back blocks, the water has nowhere to go and comes through the ceiling below it, often well away from any outside wall.
I live in a flat. Who is responsible for the roof?
In most converted houses and mansion blocks the roof belongs to the freeholder, or to all the flat owners together through the freehold, so the repair has to be arranged by whoever is responsible. Check your lease, report the leak to your managing agent or freeholder in writing, and keep photos of the damage.
Can a leak be repaired, or does the roof need replacing?
Most leaks come from one fault, such as a slipped slate, a split in a flat roof or a lifted flashing, and repairing that fault stops the water. Replacement only becomes the better choice when the covering is failing across the whole roof and repairs are no longer lasting.
Will my insurance pay for a roof leak?
It depends on the policy and on the cause. Sudden storm damage and gradual wear are often treated differently, and in a block of flats the buildings policy is usually held by the freeholder. Take photos before anything is moved and ask the insurer what they need.
Leaking Roof in South West or Central London?
From our base in Richmond we repair roofs in Richmond, Kingston, Wimbledon, Putney, Wandsworth, Battersea, Clapham, Fulham, Chelsea, Kensington, Knightsbridge and Westminster. Call 020 8049 1949 or 0777 764 6199, or send us the details.