Surface Properties

• Natural material
• No coating or surface protection required
• Permanently maintenance-free, no cleaning necessary
• Not galvanised but solid RHEINZINK

The material RHEINZINK is a natural material, which over time develops a firmly adhering patina of zinc carbonate when exposed to the atmosphere. Initially, the zinc surface reacts with the oxygen in the air, forming zinc oxide. Zinc hydroxide is then formed by the effect of water (rain, moisture), and this reacts with the carbon dioxide from the air to form a thick, firmly adhering, water-insoluble top layer of basic zinc carbonate (patina). It is this protective layer that is responsible for the high corrosion resistance of zinc.

This process does not take place simultaneously all over. First of all drop-shaped areas of greyish patina start to appear and slowly run together as the protective layer develops, resulting in the familiar blue-grey patina over the entire area. Patination may take from a few months to several years depending on the pitch of the structure covered with RHEINZINK and the length of time rainwater remains on its surface.

The quality "preweathered^pro blue-grey" was developed by RHEINZINK many years ago specifically for facades when a "finished" RHEINZINK surface is already required on handover. This was followed by "preweathered^pro graphite-grey" in 2003. A special process that is unique throughout the world allows the colour and the structure to be modified to resemble a naturally weathered surface without impairing the natural protective layer of the material and its suitability for processing. In contrast to coated materials, any scratches or minor flaws on the surface are evened out by patination.

Once the coils of RHEINZINK material have been cleaned, they are then pickled. Pickling produces a uniform shade of colour, albeit not one that can be compared with the RAL colour palette. The product is then subjected to an organic surface treatment to protect the material as far as possible from becoming marked during processing, e.g. with fingerprints. This also results improved protection during storage and shipment.

With preweathered material we recommend using facade cladding and roof coverings from a single batch to avoid any variation in the shade of grey. Should this nevertheless occur, something that cannot be ruled out with manufacture involving a natural material, the colour will even out as the above patination process takes place.