Lead Flashing Cost: What Affects the Price

A straight run of flashing along a wall abutment is the simplest detail. A chimney is more involved: it needs a front apron, stepped side flashings and a back gutter, each cut and dressed by hand to the shape of the stack and the roof covering. Valleys, bay roofs and dormer cheeks each have their own detail and their own time.

So a short chimney flashing can cost more per metre than a long, plain abutment. That is why our guide shows chimney re-flashing separately from the per-metre figure.

Lead is sold in codes that describe its thickness. Code 4 and Code 5 are typical for flashings; heavier codes cost more but suit some details better. Proper lead flashing is chased into a cut in the mortar joint, wedged and pointed, with lengths and laps kept within sizes that allow the metal to expand and contract without splitting.

Ask what code is being used and how the lead will be fixed. A quote that simply says flashing could mean very different things.

Lead is only as secure as the joint it is fixed into. If the mortar where the lead is chased in has perished, it needs raking out and repointing as part of the job. On chimneys, the whole stack may need repointing at the same time. That extra work is often why two flashing quotes differ, and it should be listed rather than hidden in a single total.

Self-adhesive flashing tape is sometimes offered as a cheaper option. It has a place as a temporary seal while a permanent repair is arranged, but it lasts a few years at most, while Code 4 or 5 lead lasts 50 years or more. Paying for tape repeatedly usually costs more over time. Our lead versus flashband page compares the two in detail.

Most flashing work needs safe access to the roof, and chimney work often needs scaffolding around the stack. Access costs much the same whatever the size of the repair, so combining jobs while the access is up can be good value.

A useful quote names the location and length of the flashing, the lead code, how it will be fixed, any repointing, and the access. It should also confirm the fault, because water near a chimney or wall can also come from pointing, flaunching or the roof covering.