Why is my roof leaking? The common causes, in order
A leak almost never starts directly above the stain. Water runs along battens, rafters and ceiling joists before it drops, so the wet patch can be two or three metres from the actual entry point.
Water coming in right now? We prioritise active leaks across Hampton, Twickenham, Teddington and the wider TW and KT postcodes.
Call 07748 750711Most domestic roof leaks are not the tiles. In order of how often we find them: chimney or abutment flashing, a slipped or cracked tile, a blocked valley or gutter, perished flat roof felt, and finally loft condensation being mistaken for a leak.
1. Flashing at a chimney or wall junction
This is the single most common cause we attend. Lead splits along old bends, or the mortar pointing above the lead washes out and water tracks behind it. The clue is staining beside a chimney breast or where a roof meets a wall, worst after driving rain from one direction.
2. A slipped, cracked or missing tile
Nail fatigue on older roofs lets one tile creep down, exposing the underlay. If the underlay is sound you may see nothing for years. If it has perished, that single tile puts water straight into the loft.
3. Blocked valleys and gutters
Leaf litter dams the water and pushes it sideways under the tiles. Leaks that only appear in heavy, prolonged rain rather than light rain usually point here, and the fix is often just a clear out.
4. Flat roof coverings past their life
Felt splits at the laps and around upstands. Ponding water finds any weakness. On a flat roof, a leak inside is a sign the covering is at the end of its life rather than a one off failure.
5. Condensation, not a leak at all
Damp that shows up in cold, still weather rather than during rain, spread evenly across the loft, is usually condensation from poor ventilation. Adding vents is far cheaper than chasing a leak that is not there.
How to narrow it down before you call
Note when the damp appears (during rain, after rain, in cold weather), where it sits relative to the chimney and walls, and take a photo of the loft side with a torch. That short description tells a roofer more than a photo of the ceiling.
FAQs
If water is coming through a ceiling or near light fittings, yes. Contain it, isolate the affected electrics and call for a make safe. If it is a faint historic stain that is dry to the touch, it can be booked normally.
Usually yes. Most leak investigations are done from a ladder, a roof ladder and from inside the loft. Scaffolding only comes in when the repair itself needs a safe working platform.
We prioritise active interior leaks across Hampton, Twickenham, Teddington and the wider TW and KT postcodes. Call and we will tell you honestly when we can be there.
Related reading
More on repairs & problems and the jobs that usually come with it.
- Clay tile roofs: plain tiles, pantiles and longevity
- Damp patch on the ceiling: leak or condensation?Repairs & problems
- Storm damage: what insurance covers and what it does notRepairs & problems
- Loft condensation: ventilation, not leaksMaterials & systems
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