Leadwork & Roof Flashing in Plymouth

Water tracking down internal chimney brickwork is almost always caused by split lead aprons, loose step flashings, or washed-out mortar in the brickwork chase. Heavy Atlantic rain hits the exposed stack, runs down the masonry face, and slips directly behind lifting leadwork into the roof space. We rake out the degraded joint mortar to a 25mm depth, replace cracked sections with Code 4 milled lead, and mechanically fix the upstands with folded lead wedges before resealing.

Thin metals or Code 3 lead are only meant for concealed soakers; when exposed on a Plymouth roof, they warp, buckle, and crack under coastal temperature shifts. We use Code 4 milled lead for chimney aprons, cover flashings, and stepped runs, stepping up to heavy-duty Code 5 for wide lead valleys and box gutters. Installing the correct gauge stops thermal fatigue from tearing the sheet when the metal expands in direct summer sun and contracts during winter freezes.

Flashband and adhesive tapes are short-term emergency patches that quickly dry out, curl up, and leak under salt air and driving rain. Worse, moisture gets trapped behind the adhesive backing, rotting the valley boards, battens, and rafter timber beneath without you knowing. A permanent trade repair involves removing the failed metal and either lead-welding a new insert or replacing the full run to British Standard overlap details.

We strip back the slate or tile courses on both sides of the valley, carefully pulling the original fixings so the surrounding roof remains intact. Once the valley is bare, we inspect the timber support boards for rot, lay fresh breathable underlay, and install Code 5 lead sheets cut to maximum lengths of 1.5 metres to prevent heat splitting. The slates are then trimmed neatly down both edges to leave a clear drainage channel and nailed back into place with copper fixings.

We grind out clean, straight chase lines 25mm deep into the mortar beds, stepping cleanly down with the roof pitch. The turned-in lead lips are secured inside the brick joints using folded lead wedges driven tight, which hold firm against coastal gale-force uplift where standard steel clips vibrate loose. We then finish the joint with high-grade, flexible lead sheet sealant rather than brittle sand-and-cement mortar that cracks away over time.

Fresh milled lead reacts with rainwater and air, creating an unstable white lead carbonate powder that washes down the roof and stains your tiles or slates. We treat all newly installed lead flashing with patination oil on the day of installation before rain can hit the surface. This oil provides a protective barrier that controls the natural oxidisation process, leaving a clean, uniform, dull grey finish that will not run.