Roof flashing problems often show up as lifted lead around a chimney, cracks where an extension roof meets a wall or damp patches that return after heavy rain. If you’ve spotted one of these signs, an inspection can establish whether the leadwork needs repairing and where water is getting in.
What does roof flashing do?
Flashing weatherproofs joints where a roof meets a chimney, wall or dormer. It directs rainwater back onto the roof covering so it can drain away. At a chimney, the apron flashing protects the downhill face, while the detail behind the stack directs water around the sides. On a pitched roof that meets a wall, stepped flashing often follows the mortar joints.
Five signs of roof flashing problems
- Lifted or loose edges. Lead that has pulled away from the wall or lifted at a joint can leave a gap where wind-driven rain can get underneath.
- Splits or tears in the lead. Look for damage at folds, corners and joints where you can see them from ground level. Even a small split can let water through.
- Cracked or missing mortar above the flashing. Gaps in the joint can let water track behind the lead and may indicate that the flashing is loose.
- Damp near a chimney breast or where an extension meets the house. Brown marks, peeling paint or damp plaster that worsens after rain are worth investigating. Water can travel before it shows indoors.
- A leak that returns after patching. If a stain reappears after the next spell of wet weather, the original repair may have missed the entry point or left the underlying defect unresolved.
Why does lead flashing split or come loose?
Lead expands and contracts as temperatures change. If a piece is too long or its fixings restrict movement, repeated expansion and contraction can eventually cause it to split. Flashing can also pull loose when fixings fail or the mortar joint deteriorates. Around an exposed chimney or wall junction, wind-driven rain can make a small gap more noticeable indoors.
Nearby defects can produce similar symptoms. Slipped tiles, cracked chimney mortar and damaged mortar around the chimney pots can all let water in. A roofer will check the surrounding roof covering and brickwork as well as the leadwork. Our guide to what a roof inspection can uncover explains what else may need checking.
Can roof flashing be repaired, or does it need replacing?
If the lead is sound and the fault is limited to a loose section or failed mortar joint, a roofer may be able to secure the existing flashing and repair the joint. If the lead has split in several places, become badly distorted or repeatedly failed because the original detail restricts movement, replacing the affected section may be the better option.
The inspection should also establish whether nearby tiles, slates or brickwork need attention. Ask the roofer to explain where the water is entering and what the proposed work will do to address it. DB Roofing’s leadwork services include chimney and apron flashing on pitched and flat roofs.
What can you check before calling a roofer?
From ground level, take a photo of any obvious gap or lifted edge if you have a clear view. Indoors, photograph damp marks and note whether they get worse after heavy rain or when the wind comes from a particular direction. Share those details when you book an inspection, especially if the leak is intermittent.
Keep checks at ground level and leave roof access to a professional. The Health and Safety Executive’s roof work guidance explains the risks of falls from roof edges and through fragile surfaces.
Arrange a lead flashing inspection in Dorset
DB Roofing inspects and repairs lead flashing around chimneys, dormers and roof-to-wall junctions in Poole, Bournemouth and across Dorset. If you’ve noticed loose leadwork or a damp patch that keeps returning after rain, contact DB Roofing to arrange an inspection or call 01202 126602.
