Lead alternatives: when they work and when they don't
Lead substitutes exist for real reasons: cost, weight and theft. They are not a universal replacement for milled lead.
Lead Flashings & Valleys
Lead does the unglamorous work that decides whether a pitched roof lasts 30 years or 80 — chimneys, valleys, parapet abutments, bay-window aprons.
Lifespan
60–100 years from properly fixed code-rated lead.
Cost / m²
Code 4 from £55/m², Code 5 from £75/m² — usually quoted by linear meter on flashings.
Category
metal
Best for
Chimney stacks, valleys between roof slopes, abutments to brickwork, bay-window apron flashings.
Where it fails
- Splits at bay-roof aprons from thermal movement on long pieces
- Mortar pointing failing above stepped flashings
- Cheap flashband used in place of proper lead
- Lead theft on accessible single-storey roofs
Our repair approach
We use Code 4 minimum, lap pieces to allow movement, and chase flashings into a proper mortar joint rather than relying on mastic alone.
Lead flashings by area
Our guides on this
Roof valleys: the highest-risk detail on a pitched roof
A valley collects the water from two slopes and funnels it into one channel. It is the hardest-working square metre on the roof.
Chimney repointing and lead flashing costs
Chimney prices are set by access first and brickwork second. Getting a safe platform to the stack is usually the largest single item, which is why doing pointing, flaunching and flashing together in one visit costs far less than three separate call outs.