VM ZINC® BASICS
VM ZINC® protection during installation and maintenance
Before Installing VM ZINC®
The roofer must ensure that:
the structure is dry, clean and free of any rubbish (nails, leaves, vegetation, etc.);
the roof timber nails are countersunk in order to avoid any contact with the VM ZINC®;
the screws are countersunk into the wooden substrate to avoid any contact with the VM ZINC®;
the structure conforms (flatness, compatibility, etc.) to the specifications.
Transportation and storage of profiled VM ZINC®
VM ZINC® must be transported and stored in dry conditions and in a constant temperature in order to avoid the formation of white rust.
White rust forms on the surface of VM ZINC® when the latter comes in contact with humidity in the absence of carbon dioxide. In this case, the protective layer cannot form and white rust appears on the surface.
Unlike the patinated layer, white rust provides no protection and leaves unattractive, indelible marks on the roof or facade. Consequently, we do not recommend installing panels that have been attacked by white rust.
Moving around on the VM ZINC® during and after installation on the roof
As a general rule, moving around on already installed VM ZINC®, is to be avoided even if the latter is protected by film. As stated in the section on crimping, it is preferable to crimp the panels as they are installed. This also avoids unnecessary traffic on the panels that have already been laid.
However, if it is necessary to walk on the zinc, we strongly advise moving around using specially designed ladders and wearing safety shoes made for slippery surfaces as Natural VM ZINC®, bilacquered VM ZINC® and pre-weathered VM ZINC® are slippery whether they are covered by film or not, particularly when they are wet.
In any case, obey the building site safety standards in force and as a minimum make sure you are always secured by a safety harness.
The VM ZINC® fitted should be protected during peripheral work (rough casting, tuck-pointing, rendering, etc). However, this protection must allow effective ventilation of the upper surface of the VM ZINC®.
Dirt
If dirt accumulates on the zinc during the installation process, it should be gently removed with a clean/dry cloth. Do not allow cleaner to attempt to use cleaning products or rub hard to remove any dirt. Remember that the patina has a self-healing nature. The dirt will be removed over time with natural rain water.
Grease and oily mark
In case of grease or oily marks, use acetone gently to remove them. Acetone is a volatile product. So please: wait for good weather, the zinc panels have to be perfectly dry - however don't wait for summer, hot temperatures are not good with acetone - clean the whole panel with a very clean cotton cloth - don't scratch the zinc.
Scratches
If a scratch appears during the installation process, you should reassure the client that the self-healing patina will minimise the effects of the scratch over time. If the scratch is especially deep or wide then the panel may need to be replaced. In general minor scratches are expected and are self-correcting.
Fingerprints
Fingerprinting can be noticeable on wall applications. Because of the "self-healing" nature of zinc, fingerprints will be obscured by the formation of the patina over time. To remove them quickly, use mineral oil available from Umicore Australia. Some mineral oils may react adversely with the zinc so be sure to use only VM ZINC® specified mineral oil.
Salt Deposit
In exposed areas, salt laden water may be blown into the joints, evaporate and leave a white residue behind. Normally rainwater itself is enough to wash away or reduce these deposits. In case of a period without rain, we recommend simply washing the zinc with hot water. In case of salt build up that cannot be removed by water, please be aware that these salt deposits do not compromise the integrity of the material and do not cause corrosion.
Colour variations
Zinc is a natural material. Slight colour variations between panels are common and expected at the early stage of the project. However colour differential will be minimized over time by the continuous formation of the protective patina which has a smoothing effect. The colour of the panels will become more and more uniform as time passes till it becomes homogeneous.
To ensure a consistent finish we recommend profiling and installing the components of a new project using a parent coil.
Protective film
Most VM ZINC® products are shipped with a protective film. The product should be installed with the protective film in place to help prevent scratches. However, the film should be removed promptly after installation since the film is not UV resistant and residues of the adhesives may remain on the metal. Umicore Building Products recommends that the protective film be removed no later than six weeks from the date of installation. As a general rule, the film must be removed from the entire surface at the same time.
Flatness
One of the distinct advantages of zinc is its malleability. The inherent softness of the material and its ductility allow it to be shaped into almost any form. Some waviness may occur especially with low thickness and can be more apparent during certain times of day depending on the angle at which the sunlight hits the cladding or the roof. This is an intrinsic characteristic of zinc and is part of the aesthetic appeal of this material which has been used for centuries.
