Lead replacement flashing is a flexible strip with the same job as sheet lead — weatherproofing the junction between a roof and rising work — but built up from a stretchable aluminium or plastic mesh with a sealing top layer. Like lead, it can be dressed into the shape of the tile by hand or with a wooden bossing mallet.
Well-known products include Ubiflex (aluminium mesh with bitumen and a UV-stable colour layer), Wakaflex (aluminium mesh with polyisobutylene) and Leadax (an aluminium carrier with recycled PVB film from laminated safety glass).
Where it is used
- The junction of a tiled roof with a chimney
- The junction with a rising gable wall or dormer cheek
- Around roof penetrations and vent pipes
- As the upstand at the wall junction of a flat roof
Advantages over sheet lead
| Aspect | Lead replacement |
|---|---|
| Weight | Much lighter, easier to handle on a roof |
| Roll length | Far longer rolls, so fewer joints and laps |
| Theft | No scrap value, so no target for thieves |
| Colour | Available in colours matching the tile |
| Handling | No lead dust and no lead residue on your hands |
Points to watch
- Service life — manufacturers typically quote expectations from around 20 years; properly installed sheet lead has a proven record of far longer. For a listed building or a detail you want to leave alone for decades, lead is often still the better choice
- Wind loading — the light material can flap where there is a large unsupported overhang. Fix it in line with the manufacturer’s instructions and dress it firmly into the tile profile
- Details in joinery — traditional cut and folded corners are easier in lead; use the preformed corner pieces the supplier offers
- Substrate — do not apply in low temperatures; most types require a few degrees above freezing and a clean, dry, dust-free joint
- Combining — do not simply stick lead replacement over existing lead; check that the adhesive or butyl bonds to that substrate
Related terms
- Sheet lead
- Step flashing
- Roof penetration
- Roof pitch
- Rainwater drainage
Want to learn more about construction terms? Visit our knowledge base at fredsdiyplans.com.