Leadwork and Your Chimney
Leadwork is often found around the base of chimneys, where the chimney stack meets the roof tiles.
This is a known weak spot in the design of most roofs and without leadwork or with failed leadwork, the roof can leak.
Lead is flexible metal that’s been used in the construction industry for hundreds of years, it has many beneficial properties:
· Is watertight
· Lasts for decades, sometimes hundreds of years
· Is bendable and can be moulded around tiles and bricks
· Can be welded easily
If you live in the UK, chances are your house will leadwork somewhere, probably on the roof or near to a chimney.
Unfortunately, there are some reasons why leadwork may fail:
· It wasn’t secured to the brickwork well enough and over time has come loose (often caused by failed brick pointing).
· The lead used by the installer was too thin and has now split.
· The installer used a length that was too long and the contraction/expansion caused by changing temperatures has resulted in splits.
There are three sections of lead around a typical chimney, any or all of them may need replacing, it depends on why they’ve failed:
· The step flashing
· The back gutter
· The front apron
How Long Does Lead Last?
Unfortunately, poorly installed thin lead can fail early, leading to leaks.
The photo below shows rainwater being discharged onto leadwork, it should be no surprise that this wear and tear has damaged the lead:
One of the most common reasons why lead fails is that it was fitted in long lengths rather than in small sections.
Lead is a very soft metal that experiences considerable expansion and contraction caused by the changing temperatures through the seasons. This provides an allowance for thermal expansion.