Why is my roof leaking? Common causes and fixes

What to do straight away

Before any repair, limit the damage inside:

• Move furniture and belongings away from the drip and put a bucket or container underneath.
• If water is near light fittings, sockets or the fuse board, switch off the affected circuit.
• If a ceiling is bulging with water, keep people away from it.
• Take photographs of the damage and note when the leak appears, such as only in wind-driven rain.
• Do not climb onto the roof yourself, particularly in wet or windy weather.

Slipped, cracked or missing tiles and slates

Tiles and slates are the first line of defence. Wind, frost and age can crack them or cause them to slip out of line. Sometimes a tile moves by only a few millimetres and still looks fine from the ground, yet lets driving rain through.

The fix is usually to refix or replace the affected tiles and check the underlay beneath. Where many tiles are failing or fixings have corroded, a wider section may need to be stripped and relaid.

Failed flashing and leadwork

Flashing seals the junctions where the roof meets a chimney, wall, dormer or valley. Lead can split, lift or come away from brickwork, and the mortar or sealant holding it into the wall can crumble.

These leaks often appear only in heavy or wind-driven rain. Repairs range from re-dressing and resealing existing lead to replacing the flashing completely with properly fitted new lead.

Ridge, hip and verge problems

Ridge and hip tiles along the top and edges of a roof are traditionally bedded in mortar, which cracks over time. Loose ridges let water in and can be dislodged in high winds.

Repairs can involve rebedding in mortar or fitting a mechanically fixed dry ridge system, which avoids relying on mortar for weatherproofing.

Gutters, valleys and drainage

Not every leak is a roof covering failure. Blocked or leaking gutters overflow behind the fascia and soak walls and roof timbers. Leaves and moss in a valley can dam water so it backs up under the tiles on either side.

Clearing blockages, correcting gutter falls, resealing joints or replacing tired roofline sections often resolves these leaks at lower cost than roof work.

Flat roof leaks

On flat roofs, water usually gets in through splits, blisters, failed seams, lifted edge trims or poorly sealed upstands where the roof meets a wall. Ponding water speeds up wear.

Small defects can be repaired. When leaks keep recurring in different places or the deck has become soft, replacement is often the better long-term option.

Condensation that looks like a leak

Damp in a loft is sometimes condensation rather than rain. Poor ventilation lets warm, moist air from the house condense on cold surfaces. Signs include damp spread widely across the underside of the roof and dripping in cold weather even without rain.

Getting the leak fixed

Rayner’s Roofing investigates the likely source of a leak rather than simply treating the visible symptom. Our roof repair work covers slipped and broken tiles, flashing, ridges, storm damage and flat roof problems for homeowners across our area.

Frequently asked questions