Zinc has a long tradition as a building and roofing material and has been produced since the beginning of the XIX century.
At that time, commercial zinc lacked the purity of today’s zinc and was processed alone, unlike current zinc roofing that is a zinc-copper-titanium alloy.
This material has become increasingly popular, particularly in France and in the Benelux countries. The roofs of Paris, for example, are coated with more than 20,000 tonnes of zinc. In Berlin was the famous architect Karl-Friedrich Schinkel (1781-1841) who most skilfully used the zinc in the buildings he designed.
The reasons for this popularity are numerous and diverse: zinc is durable, can withstand wind gusts up to 140km, is maintenance-free and allows for complicated shapes. Safety is another advantage as it does not ignite flames when a fire occurs.
Aesthetically it is a neutral material that harmonizes well with other materials used in the construction and satisfies all the ecological requirements of modern times.
Since its inception, this material used in the area of facade coverings and coatings has been improving, both in terms of mechanical properties and resistance to atmospheric environments.
In its early days, zinc was used purely without additives, different from current days as we use zinc added with titanium and copper, namely. It is, therefore, a zinc-copper-titanium alloy, of composition strictly controlled by international standards, the material that we use today and that is seen on Dublin´s roofs.
The durability of a zinc roof or facade is proportional to the thickness of the sheet used. Recent research with this zinc alloy indicates predictable durability of up to 100 years.
Zinc is a nonferrous metal, which protects itself naturally, gaining a patina over time. It does not rust and has excellent resistance to weather:
- 90 to 100 years in rural areas.
- 40 to 60 years in an urban setting.
- 30 to 40 years in a normal industrial environment.
- 40 to 70 years in a maritime environment.
The bright appearance of the zinc at the exit of the lamination process, in the face of exposure to the environment, gradually turns into a grayish matt shade. It is the result of the formation of a zinc carbonate patina on the surface of the metal.
Like most metals, zinc reacts in contact with the oxygen in the air, giving rise to oxidation phenomena. This oxidation, contrary to what happens in ferrous metals, is not a destructive phenomenon for the material, quite the contrary, its existence gives rise to the creation of a layer of protective material called the patina.
This layer of protection is responsible for the high anti-corrosive capacity of zinc.
A zinc coating is composed of two elements:
- the cover, in zinc plate.
- the bubble-shaped draining membrane.
The pinhole drainage membrane allows avoiding contact between the zinc plate and the incompatible supports facilitating the evacuation of the condensation water that appears in the inner part of the zinc thanks to the presence of bubbles that create a breathing space in the cover.
General precautions with the Zinc Sheets:
Despite its excellent resistance, Zinc must be handled with certain precautions, in particular:
- avoid throwing the zinc sheets to the floor
- avoid sliding on overlapping surfaces.