Sealing lead flashing?

[sasolshares]

Hi,
I recently had a conservatory built with glass roofing rather than polycarbonate. Runoff from the lead flashing seems to leave white marks on the glass roof panes closest to the wall.
Should the lead flashing have been coated with anything to reduce surface oxidation?

Many thanks

 

[Nige F]

yes it should ,Patination Oil.......wonder why it wasn`t

 

[sasolshares]

Thank you very much, I suspected it should have been coated with something!