Rust discoloration on lead flashing

[pejoli]

Hi All,

Just had a dormer loft conversion, with a mansard roof at the back, some sort of membrane on the flat roof of the dormer, what looks like asphalt material forming the roof flashing into the brick work and overlapping the lead flashing around the top and cheeks of the dormer windows. The lead has been pattenated, but when it's rained, we now have a copper/rust colouring down the lead.

Any idea what could be causing it other than the obvious that something somewhere is rusting- we've had a builder look at it, and he can't figure it out? There's nothing obviously exposed, so is there anything else that's commonly used 'up there'? I think some of the surface around the edge has a coating of what looked like aluminium paint - the roof itself appears fully waterproof - so far !

 

[Nige F]

Staining from when it was stored in a roll on a damp concrete floor Don`t expect a builder to know that . Does no harm

 

[^woody^]

Any chance of a picture?

 

[datarebal]

not all lead will do this, just certain brands..look forward to the pics

 

[pejoli]

not all lead will do this, just certain brands..look forward to the pics

Thanks for the replies - on holiday in sunny Rhodes at the moment - will post some pictures when I get back

 

[RedHerring2]

don't forget the topless holiday pics!

 

[pejoli]

don't forget the topless holiday pics!

Well ... Ok, I'll get the wife to take a couple, but I must warn you, I'm no oil painting!

 

[SASroofer]

Sounds like they have used a cast lead and not milled to me. Shouldnt doany harm, basically used a cheaply made lead is all, though all Iwill ever use is milled because cast lead feels too 'tinny'.