Leadwork & Roof Flashing in North Aberdeenshire

Where lead goes on a roof

• Valleys, where two roof planes meet
• Soakers and stepped flashings where a roof abuts a gable or chimney
• Front aprons at the low side of a stack
• Back gutters behind a chimney — the single most common leak point on a pitched roof
• Dormer cheeks, tops and parapet gutters
• Around roof windows and soil vent pipes

Bay lengths and why lead splits

Lead expands and contracts a long way with temperature. If you run a single continuous length that is too long, it has nowhere to move, so it tears itself — usually along a fixing line, usually about two years in. Code 4 and Code 5 flashings should be run in bays of no more than about 1.5 metres with proper laps between them. We see split lead constantly and the cause is nearly always one long piece where there should have been three.

We use Code 4 for most flashings and soakers, and Code 5 where the detail is exposed, walked on, or in a valley that carries real volume. Both are dressed on site to the shape of the slate rather than forced flat.

Cement fillets

A mortar fillet smeared into the join between roof and wall is a cheap substitute for a soaker, and it is on a great many houses around Buchan. Mortar and stone move at different rates, so it cracks, and once it has cracked it holds water in the joint instead of shedding it. Where we find one, we take it off and put in stepped flashing chased into the wall, which is the detail that should have been there.

Staining down the wall

New lead weathers to a white carbonate that washes down and stains the stone below it. It is harmless and it is avoidable — a coat of patination oil on the day it goes on stops it. It takes ten minutes and it is the difference between tidy leadwork and a streaked gable.

Leadwork is part of every re-roof and most chimney repairs we do, and we take it on as a job in its own right.

Questions about leadwork & flashing