Let me educate you Ken.....
There is evidence that the Romans started installing zinc to roofs. At the turn of the century (1900) the powers that be decided Paris needed to double its population but they had run out of land. The best viable option was to add an extra storey to every building in the city. Without causing extra work to the foundations they needed a lightweight solution, timber and zinc was decided. If you look at an aerial shot of today's Paris you will see that 90% of the roofs are covered it zinc.
Zinc out performs lead in every department. It has always been seen as a lead replacement rather than an alternative. Lead is a dirty material, toxic to humans and the environment. It will eventually be banned such as asbestos etc.
We are now replacing church lead roofs with zinc. The only zinc roof I have replaced was 124years old and had been installed badly.
It is only the recent introduction of widely used hard woods that have seen adverse affects on zinc. Oak, cedar, cherry woods contain natural oils which leech over 6 months when installed. It's these oils which can discolour and or eat into the zinc material. If you know the facts the building can be designed to incorporate both materials without compromise to either material.
Unfortunately it's dinosaurs within the construction industry that believe lead has always been used and we should continue to do so. The amount of poor lead work I have seen over the years is astonishing. I would guess that 80% of the jobs I have seen haven't been completed by the book and this will only add weight to the poor performance of a dated material.
I have been a zinc roofer from the age of 18 and this is all I have ever done. It's a growing industry will a declining labour pool. Times are good.
