Badly rusting lead flashing

[David John Booton]

Hello, I was wondering if anyone could help with some advice, I had some extensive renovation work done last year and the lead flashing is starting to corrode and rust really badly. It looks like the tannic acids in the Red Cedar cladding are reacting to the Lead. Has anyone else experienced this and what would be the best way to resolve it. I was thinking of possibly applying a rust remover solution first and then possibly painting the flashing with Bitumen or something similar.

 

[Exedon]

It's not rust it's staining from the cedar also get a certain amount with siberian larch .
Will clean off with strong detergent nylon pan scourer on bad bits .
Then several protective coats my preference is lead cote but patination oil ok as well .
Don't paint it will look dreadful!

 

[datarebal]

Over time it can damage the lead if left unprotected.
Acid etching .

 

[Exedon]

All the information/notices I've seen about lead reactions to tannic acid containing timbers (green oak is another) points to direct contact been main problem.
They's timbers and lead in direct contact should be seperated by a class A building paper. Water run of from they's timbers on to unprotected lead seems to be regarded as a nuisance (staining) rather than harmful..
I've got several outbuildings roofed with cedar shingles so well aware of this problem!

 

[datarebal]

Bp has a short life span when constantly damp.
As it would be trapped between a shingle and a lead or other metal soaker or flashing .
Under a gutter and on top of the sole for example is fine.
Bitumen coating is superior

 

[^woody^]

That looks too localised and too brown to be tannin bleed.

It looks like reaction rust from random steel fixings.

Even supposing it is tannin, that would indicate untreated cedar and a poor installation.