1. Maximum length
Each system has maximum lengths that must not be exceeded. Please consult the technical brochures of each system for this information and for the specific fixings to be used. If your project exceeds the standard maximum lengths provided, please contact your Technincal Sales Manager for a bespoke solution.
2. Protecting the VMZINC during installation
As a general rule, please avoid treading on the VMZINC when installed, even if the latter is protected by a film. However, where required, it is advised that ladders are used, designed for this purpose, and that security footwear is worn, suitable for use on slippery surfaces. Indeed, natural VMZINC, Bilacquered VMZINC and Pre-weathered VMZINC are slippery, whether covered or not with their film and in particular when wet. Please ensure that all safety rules in effect are complied with on the worksite at all times and that a safety harness is used. For works being performed near to the VMZINC (plastering, jointing, cementing, etc.), the VMZINC already installed must be protected. Furthermore, it must be ensured that this protection does not block the aeration of the upper surface of the VMZINC.
1 Warm roof Construction (non-vented)
In order to meet current trends in terms of construction and the introduction of warm complexes in roofing, VMZINC has developed VMZINC PLUS. With VMZNC PLUS, a support structure can be chosen without air space. In this event, the zinc is placed with the VMZINC Membrane directly onto the support. The use of the VMZINC Membrane is mandatory for warm roofs.
On the roof’s cold surface, in most cases the outer surface, the VMZINC Membrane is applied underneath the VMZINC PLUS. This underlay membrane, which is water resistant and vapour open guarantees the management, distribution and evacuation of any possible humidity that may have accumulated between the insulating layer and the VMZINC PLUS coating when building the roof.
Apply a vapour barrier on the roof’s warm surface, in most cases the inner surface, corresponding to the climate class within the building. This application process is performed in compliance with the manufacturer’s guidelines. Carefully seal the vapour barrier’s overlaps. For this type of non-ventilated construction, only VMZINC PLUS can be used as it features a specific underside coating. VMZINC PLUS is worked in the same way as traditional zinc. The soldering preparation process requires specific skills. All information on soldering can be found in our brochure on this topic.
2 Cold roof Construction (Vented)
When installing a roof or facade cladding made from traditional zinc, an air space must be provided for underneath the VMZINC. Contact with external air guarantees the CO 2 supply required for the formation of the protective patina on the VMZINC. Therefore, aeration of the lower surface of the VMZINC is essential for its durability. The best means of aeration is a continuous air supply at the bottom and top of the roof or cladding. The installation of a small-mesh grating at the air inlets will prevent access by insects, birds and rodents, etc. The depth of the air space must be at least 50mm for roofing and 38mm for cladding. The total area covered by air inlets at the bottom and top of the roof must always be 1/1000th of the cladding, with a minimum width of 10mm for a continuous air inlet/outlet. A total aeration area at the top of the roof of 1.5 times that at the bottom is recommended.
For roof planes exceeding 13 m, intermediary air inlets should be provided or the air space increased. In this event, please contact our technical services.
When used on a cold roof or on a façade the VMZINC needs to be ventilated. VMZ Zinc plus should be used when installing over Plywood or in a warm roof application. VMZINC can be used for renovation projects or new build.
Information courtesy of https://www.vmzinc.co.uk