General Environment
The durability of galvanised zinc coated products is dependent on:
- The environment it will be installed in.
- The grade or weight of the zinc coating used.
- The degree and extent of the maintenance that will be undertaken over the life of the product.
Performance of galvanised zinc coated flooring products is affected by:
- The cumulative effects of the weather to either the underside surface or moisture ingress of the top surface.
- The amount of dust (which can hold moisture) that settles on the product.
- Any other wind-blown deposits that may settle on the product, promoting corrosion.
- Proximity to the ground in subfloor areas with little or no ventilation.
Condensation or other deposits should be prevented from accumulating on the Dimond Flooring System underside by providing adequate ventilation. A protective barrier must be provided if dampness is possible on the underside of the steel flooring sheet.
Limitations of Use
The use of galvanised steel flooring sheet should be avoided:
- In areas where high concentrations of chemicals are combined with a high humidity, unless an appropriate protective coating system is applied to the underside surface and fully maintained for the design life of the structure. In this situation the system remains wet for long periods of time, causing a rapid consumption of the galvanised zinc coating and eventual red rusting of the base metal.
- Where the galvanised surface is being exposed to continuous moisture, without a chance for the surface to dry out, unless an appropriate protective coating system is applied to the underside surface and fully maintained for the design life of the structure. For example, where used as the cover slab of a water tank.
- In or near marine environments, where the prevailing wind carries marine salts, unless an appropriate protective coating system is applied to the underside surface and fully maintained for the design life of the structure.
- In areas surrounding chemical or industrial storage buildings where any chemical attack may lessen the life of the structure or wind-driven chemical fumes may attack the galvanised coating, unless an appropriate protective coating system is applied to the underside surface and fully maintained for the design life of the structure.
- When in contact with or laid directly on ground.
- When in contact with timber and especially treated timber such as CCA (copper chrome arsenic) without the use of an isolating material such as Malthoid (DPC) between the timber and galvanised steel flooring sheet.
- When used in sub-floor areas with less than 450mm ground clearance.
- When used in sub-floor areas where ventilation does not comply with NZS 3604 Clause 6.14.
Chemical admixtures may only be used with Dimond Flooring Systems if they are compatible with galvanised steel.
Where the top surface of the slab is exposed to moisture, use of the Dimond Flooring System without an appropriate coating system (which is fully maintained for the design life of the structure) and/or adequate crack control to the top surface of the concrete slab should be avoided. Moisture seeping through cracks which are not effectively sealed or which do not have adequate crack control can combine with oxygen to the extent that corrosion of the galvanised steel sheet may occur.
