Problems with Zinc Roofing

[Ian]

I've noticed that quite a few members of the forum are using or planning to use zinc roofing. It's a system of roofing that has been around for many decades and can be trouble free if detailed correctly however I'm also aware that there have been increasing numbers of problems over recent years with zinc roofs where the roof build-up has been incorrectly specified and zinc can corrode through in less than 5 years if the roof build-up is not what it should be.

 

The attached report from Denmark is a good explanation of the issues to look out for.

Durability_problems_with_zinc_cladded_roofs_due_to_inproper_underlays_Erik_2014_01_15.docx

[Alexphd1]

Very good reading. There is also a treatment on the underside of zinc now to prevent this, I don't know if I would trust this as long term solution. 

[scottishjohn]

I talked to a uk zinc roof supplier a couple of years ago and he stressed very much the need for a constant ventilation space under it .

for a supplier to stress that on first contact was enough to put me off the system .

Its expensive enough and then to have to build another sarking board roof under it --too much for me --same as you would do for a "scottish" type slate roof ,

but instead of costing £30-£80sqm its £150sqm for top layer

I think If i really wanted roof to look like that then the insulted panel type the kinpspan and others supply  would be the way

you are getting up  to  0.015u roof  in one layer and the look you want 

and as phonelic is bonded to underside --no moisture problems --ever

Edited July 5, 2019 by scottishjohn