The many examples of zinc roofs being renovated after a hundred years of loyal service in Europe are perfect proof of zinc's resistance to corrosion.
The reason for this longevity is that zinc protects itself by developing a patina that gives it an exceptionally long life span:
VM ZINC® reacts to the main components of the atmosphere particularly in the presence of H2O (water), SO2 (pollution), NaCl (sea spray) and CO2 (CO2).
The first reaction of titanium zinc to oxygen and water is the formation of zinc hydroxide Zn (OH)2, which, when there is sufficient concentration of CO2 in the air, allows the protective layer of patina or zinc hydroxycarbonate to form.
It is therefore important that the surfaces of the VM ZINC® are ventilated so that there is a sufficient supply of CO2 to allow the formation of the protective patina. This applies particularly to the underside of the VM ZINC®.
VM ZINC PLUS®, a VM ZINC® titanium zinc with a protected underside and tested according to ASTM 968, meets the requirements related to a lack of sufficient ventilation of the underside of the titanium zinc. This product is mainly intended for warm roof applications, where an insufficient supply of CO2 to the underside of the titanium zinc prevents the formation of the patina. It is also intended for solid wood or reconstituted panels the compatibility of which is compromised by the accumulated effects of humidity and the type of treatment.
