Common Causes of Roof Leaks

Flashing seals the join wherever a roof meets a chimney, wall or valley, and it is one of the most common leak points we find. Once lead cracks, lifts or perishes, water tracks straight through.

The most visible cause, and often the easiest to fix – a gap in the tiling, however small, is enough for wind-driven rain to get past the felt beneath. Slipped tiles from failed fixings and frost-cracked tiles are both common across South Wales.

Gutters aren’t part of the roof covering, but a blocked or overflowing gutter forces water back up under the roof edge instead of away from the building, soaking fascias and the timbers just above them.

The felt beneath your tiles is a secondary barrier, and on older roofs it can dry out, crack and tear with age, particularly where it has had years of sun and frost cycling. Once it fails, tiles alone are not enough to keep water out during heavy or driving rain.

Not everything that looks like a leak actually is one. Poor loft ventilation can cause condensation to form on the underside of the roof, which drips and stains ceilings in a very similar way to a genuine leak – telling the two apart matters, since the fix is completely different.