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Installation Prior to Installation: Care and storage of COLORBOND® steel, ZINCALUME® steel and zinc coated steel prior to installation is vital to the life of the product when installed. If not required for immediate use, stack sheets or bundles neatly and clear of the ground, and provide cover as necessary to protect the sheeting from rain or moisture. A process called capillary action can draw water in between closely nested sheets or wraps. This may lead to a wet storage stain and reduced life expectancy. If packs become wet the sheets should be separated without delay and the surface moisture removed with a clean cloth. The sheets should then be stacked so that air circulation completes the drying process. Moisture which penetrates between sheets of COLORBOND® steel can cause temporary softening of the paint film and the possibility of a minor colour change of some paint finishes. After drying, the coating will revert to its original state. Take extreme care with the surface until it has been dried and the coating hardness returns to normal. Moisture penetrating between sheets of GALVALUME® steel or galvanised steel can cause a corrosion or wet storage stain. Table 1 gives guidance on restoration of damaged sheeting. Table 1: General approach to the restoration of corrosion damaged zinc-coated or GALVALUME® steel sheet Cleaning Priming and Finishing 1. Remove dirt by washing with water. 2. Wipe off greasy deposits with paint thinners. 3. Remove any corrosion product by wire brushing, taking care not to unnecessarily remove any of the metal coating. 1. Select paint system with due regard to environmental requirements. 2. Follow the paint manufacturer's instructions explicitly. 3. Do not mix different proprietary brands of primer and finisher. 4. Apply two finishing coats in addition to the primer. 5. Care should be taken to provide adequate ventilation as some compounds may be toxic. 6. Where possible, contact with the skin should be avoided. During Installation: When sheets need to be cut on site the most suitable technique is with nibblers or power saws with metal cutting blades (tin snips can be used although they are difficult to use on profiled sheeting). The use of cutting discs and grinding wheels is not recommended as they generate very hot particles which can damage the coating. BlueScope RECOMMENDS THE USE OF COLD CUTTING SAWS WITH APPROPRIATE BLADES. Don't forget to clean up each day. Offcuts and other metal scraps, such as pop rivet stems and fasteners, if left on COLORBOND® steel, may cause rust stains which detract from the finished appearance. Swarf (steel debris produced by drilling and cutting etc) should be swept or hosed from the job each day. Care should be taken if hosing off a roof into gutters already installed. The swarf should not be left to sit in the gutters. Maximum care should be taken when attempting to detach swarf which has become stuck. This can be done, but no action which is likely to remove the paint or metal coatings should be attempted. For critical applications, inspection of the job should be made after two weeks when rain or condensation will have caused any remaining swarf to rust, and will highlight affected areas for a more thorough cleanup. Sheets should not be dragged across others as scratching will result. Spray packs should not be used to repair any scratches. The paint fades differently. Small scratches are best left alone. If the damage is severe it is best to replace the panel. Never use black lead pencils for marking galvanised, ZINCALUME® steel or COLORBOND® steel. Black lead pencils are made from graphite which will react with the coating on these products resulting in corrosion of the coating. The answer is to use any colour pencil but black and clean off any markings as soon as possible. Prevention of condensation: Condensation forms under/on roof sheeting when the sheeting becomes colder than the air in contact with it. Water vapour carried in the air then condenses on the colder surface of the roof sheet. To minimise the risk of water damage to ceilings or corrosion related to condensation under steel roof sheeting, a vapour barrier should be provided under the sheeting to prevent contact between the moist air in the building and the roof sheeting. Reflective foil laminates (sarking) which are commonly used to provide heat insulation under roof sheeting can serve a dual function as a vapour barrier, by thoroughly sealing the foil overlaps with moisture impervious adhesive tape. The laps should be about 100 mm and kept in close contact when positioning the laminate so the tape can be readily applied. The laminate must be allowed to drape between the roof supports so that the cold temperature of the roof sheeting will not be transmitted to the laminate by contact. If this were to happen condensation could form on the underside of the laminate and may drip into the ceiling space. Ventilation of the ceiling cavity may assist in the reduction of condensation however it has been shown that ventilation will not completely eliminate the condensation cycle. In certain marine situations ventilation may also carry salts into the roof cavity which will, in the presence of condensation, lead to accelerated corrosion attack. Fasteners: It is vital the performance of fasteners (screws/rivets) used to fix cladding and accessory materials have the same service life as the cladding product with which they are to be used. The recommended selection of fasteners for these jobs is of paramount importance for long term structural performance and aesthetics. Table 1 gives the fastener metal type recommended for ZINCALUME® steel and for the various grades of COLORBOND® steel. It is recommended that fasteners used, comply with Australian Standard AS 3566. Washers containing significant levels of conductive carbon black fillers are NOT suitable for use with COLORBOND® prepainted steel, particularly in marine environments. Therefore fasteners should be assembled with substantially carbon - black - free washers. Fasteners containing Stainless steel, lead, and copper containing alloys should not be used in conjunction with galvanized, ZINCALUME® steel, and all grades of COLORBOND® steel except COLORBOND® Stainless steel in which we recommend the use of Stainless steel. For COLORBOND® Stainless steel we recommend the use of stainless steel fasteners. Where accessory fasteners such as pop rivets are required, they should be manufactured from aluminium when fastening Galvanized, ZINCALUME® steel, COLORBOND® XRW steel, COLORBOND® Ultra steel and COLORBOND® Metallic steel. However, in the case of COLORBOND® Stainless steel, compatible stainless steel pop rivets should be used. Table 1 Product Appropriate Fastner Type COLORBOND® XRW, XMA & COLORBOND® Metallic steel ZINCALUME® AZ150 steel Fasteners conforming to AS 3566 Class 3‡ COLORBOND® Ultra steel COLORBOND® XRW* steel (* Note: Applies to COLORBOND® XRW Steel used 200 - 400m from marine environments i.e. "severe" environments). Fasteners conforming to AS 3566 Class 4 (Note: Stainless steel fasteners which conform to AS3566 Class 4 are NOT recommended for use with COLORBOND® XRW or COLORBOND® ULTRA steel.) COLORBOND® Stainless steel Quality stainless steel fasteners Fasteners conforming to AS3566, class 3, should not be used within 400 metres of the ocean or other severe marine influence. This information is intended as a guide only. For detailed assistance with your particular application, please contact BlueScope Steel.