Density: 7.18+ 0.02 g/cm³

Any work involving VMZINC must allow it to expand and contract freely. The linear expansion of VMZINC is 0.022 mm per meter and per degree centigrade.

Example: In United Kingdom and the Republic of Ireland, the temperature range to bear in mind is from - 20°C in mid-winter to + 80°C on the surface of the metal in the sun at the height of the summer. Assuming an ambient temperature of 20°C during installation, we have to take into account: An additional 60°C (expansion) 40°C less (contraction) For a 10 meter long panel: anticipate an 0.022 mm x 10 x 60 = 13.2 mm increase in length anticipate 0.022 mm x 10 x 40 = 8.8 mm contraction.

To avoid micro-cracks in the VMZINC to the right of the folds, do not work it when the temperature of the metal is below 7°C.

Contact with the outside air provides the CO2 required to form the natural patina of VMZINC. Without the presence of outside air VMZINC does not protect itself and if there is any condensation, a chemical reaction can occur. As a result there can be corrosion on the underside of the VMZINC which is not visible until holes appear on the outer skin. Therefore, to ensure the durability of VMZINC fixed on roof boarding its underside must be ventilated. The best ventilation is ensured by two continuous air inlets: one at the bottom and the other at the top of the roof slope or cladding. For installation on roof boarding, the underside of the latter and thus the underside of the VMZINC will be ventilated. If it is impossible to realise this type of ventilation, it must be replaced by another air inlet system such as roof ventilators (slopes > 21°) or air vents. These air inlets are to be carefully spaced to ensure that the entire underside of the metal is ventilated. Fixing fine mesh (<2 mm) to all the air inlets will deter insects, rodents and birds from entering. The minimum depth of the air space under the roof boarding must be 40 mm. The total area of the air inlets (eaves and ridge) is 1/1,000th of the surface area of the roof, with a minimum width of 10 mm in the case of continuous ventilation.

In general we advise planning a total area for ventilation at the ridge that is 1.5 times greater than at the base of the roof. For slopes greater than 13 m long, intermediate air inlets should be planned for. In most cases, a layer of insulating material is placed below the ventilated space. In order to avoid the risk of poorly installed insulation obstructing the air space, or of the insulation getting wet as the result of condensation, a breather membrane is required on the top side of the insulation. This breather membrane must be vapour permeable and end in the gutter, the box gutter or on the outside of the building. This breather membrane can also prevent convection currents of (cold) outside air entering the building. Given the increasing level of insulation in buildings, the installation of an effective vapour control layer on the warm side of the insulation is required. The use of "PLUS " type VMZINC the underside of which has already been protected during production, means that installation can be done without ventilation of the underside (Natural VMZINC PLUS, QUARTZ-ZINC® PLUS or ANTHRA-ZINC® PLUS).

Wood varieties that may or may not be placed in contact with VMZINC Compatible varieties Incompatible varieties Fir (red or white) Larch Spruce Oak Pine Chestnut Poplar Red or white cedar   Douglas pine   All wood varieties with a pH < 5

Compatibility of wood treatment products with VMZINC If the wood is treated, the compatibility of the treatment products with VMZINC must be checked (see table below). Indicative table of wood treatment products* Type of treatment Components Compatibility with VMZINC * Class Non-fixing metal salts Single component salts used in water (fluorine, boron or copper) NO C1 Metal fixing salts Complex metal salts containing chromium to fix the active metals (CCA, CCB) Study in progress (consult manufacturer) C1 to C5 Organic products Contain oil solvents YES C1 to C3 Emulsions Use water as a vehicle combined with non-hydrosoluble synthetic substances YES C1 to C2 Mixed products Combined metal compounds (copper and boron) with synthetic molecules To be determined (consult manufacturer) C1 to C4 Creosote Compound of active substances produced from hard coal distillation To be determined (consult manufacturer) C4 *always refer to the manufacturer's notice for the product used

Compatibility of glues and mastics with VMZINC If less traditional decking is used (e.g. wood panels), the compatibility of all the decking's components with VMZINC (e.g. glues) should be checked, and, if applicable, the possibility of ventilating the under-surface of the VMZINC (see table).

Indicative table of glues and mastics Compatible products* Incompatible products* Polyurethanes Acetic silicones Non-acetic silicones Acid epoxides MS Polymers Ureas / melanin / phenol-formaldehyde (wood or panel gluing)   Acrylics (depending on the reagent used) * always refer to the manufacturer's notice

Use of wood above VMZINC Incompatible wood varieties may not be used above VMZINC elements (e.g. weather-boarding with incompatible boards or panels above the VMZINC). Incompatible timber wash, treatment products or tanic acids will quickly attack the zinc and cause the formation of unattractive stains.

Direct contact with products such as fresh concrete, plaster, bitumen, mortar and structures containing substances that are aggressive towards VMZINC. Contact with metals such as copper, unprotected or ungalvanised iron, natural lead is forbidden. Only galvanised steel, natural lead protected by a patinating oil, FLEXUM® lacquered lead, aluminium and austenitic steel can come in contact with VMZINC.

Heating oil soot resulting from imperfect combustion landing on the zinc causes irreparable damage. Regular maintenance of furnace burners and the use of fuel that meets standards prevent this damage. Using chimney "caps" may lead to aggressive deposits on the VMZINC. Use of an uncovered finishing cone is therefore recommended for fuel oil heating chimneys.

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 VMZINC.

The screws are countersunk into the wooden substrate to avoid any contact with the VMZINC. The structure conforms (flatness, compatibility, etc.) to the specifications.

VMZINC 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 VMZINC 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 patined 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.

As a general rule, the film must be removed from the entire surface at the same time, immediately following the installation of VMZINC.

Exceptions to this rule: Roofs: when the roofer still has to walk on it to install flashings. Roofs: when people still have to walk on it to do other work such as masonry, joint filling, rendering walls, installing windows, safety equipment, lighting equipment, etc. Facades: when the cladding is close to the ground and there is still work to be done around it, etc. Under no circumstances must the film be left on installed VMZINC for more than a month.

Pre-weathered QUARTZ-ZINC® and ANTHRA-ZINC® are produced using a surface treatment on Natural VMZINC . As with all patinas, this change in the crystalline structure of both surfaces of the metal evolves with time.

The pre-weathering treatment completed at the plant gradually evolves and coalesces over time with the naturally formed zinc patina. To ensure a consistent finish we recommend profiling and installing the components of a new project using a parent coil.

As a general rule, moving around on already installed VMZINC, 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 VMZINC, bilacquered VMZINC and pre-weathered VMZINC 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 VMZINC fitted should be protected during peripheral works (rough casting, tuck-pointing, rendering, etc). However, this protection must allow effective ventilation of the upper surface of the VMZINC.