Roofing & Cladding Manufacturers
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Roofing & Cladding Manufacturers |
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| Design and Performance Requirements for Metal Cladding |
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1.0 Design Complete the design of the Coverworld Cladding System in accordance with BS5427 Part 1 and the requirements of the Coverworld Specification. 2.0 Loading 2.1 Wind Loading Wind Loading is to be calculated appropriate to location, exposure, roof height, building shape and size in accordance with BS 6399 : Part 2 2.2 Imposed & Snow Loading Imposed & Snow Loading is to be calculated in accordance with BS 6399 : Part 3 2.3 Dead Loading Where appropriate dead loading is to be included in the design. 3.0 Deflections Deflection is to be limited to: 4.0 U value calculation. The U value requirement is to be determined by Building Regulations, approved Document 'L'. Coverworld twin skin, (built-up), systems will comply using Covergrid spacer system and an appropriate type and thickness of insulation. Other factors such as detailing at junctions and air tightness have a major influence on the overall result. 5.0 Fire Resistance Coverworld steel sheeting is non combustible and will not
contribute to a fire. Coverworld coated steel sheeting achieves
the following; Coverworld coated steel sheeting achieves a Class O rating in the Building Regulations. 6.0 Materials Coverworld steel sheeting is profiled from alloy coated flat steel sheet manufactured to EN 10147:1992. 7.0 Finishes Coverworld steel sheeting has a reverse coat of grey polyester.
The exposed face is supplied in one of the following finishes. 8.0 Colour A full colour range for each coating type is available as detailed in data published by Coverworld. Lighter colours are recommended for roofing.
9.0 Fixing of Sheeting For Coverworld double skin construction do not line out building completely before installation of outer sheets. Cut sheets and flashings to give clean true lines, with no distortion. Remove burrs and any lubricant. Lay Coverworld sheets with exposed joints of side laps away from prevailing wind unless shown otherwise on drawings. Cut openings in Coverworld sheets for outlets, vent pipes, flues, etc. to the minimum size necessary, Reinforce edges of openings. Ensure that raking cut edges at hips and valleys are fully supported. Ensure that ends of sheets, and end laps are fully supported with fixings at top of lap. Drill all holes and install fasteners perpendicular to the surface of Coverworld cladding. Position fasteners at regular intervals in straight lines, centred on support bearings. Locate fasteners centrally within holes that are oversized. Remove dust and any other foreign matter before finally fixing sheets into position. Install fasteners to correct tightness using any special tools recommended by the fastener manufacturer. When used, screw guns must be fitted with depth sensitive devices and used at the correct speed. Protect Coverworld sheets adequately during fixing and up to Practical Completion against mechanical damage and disfigurement. Rectify any defects as quickly as practicable to minimise damage and nuisance. Check fastenings on completion and adjust as necessary to ensure that they are watertight and sheeting is secure but not buckled or distorted. Paint all cut edges to match face finish. 10. Fixing of Rooflights Size fixing holes in accordance with sheet manufacturer's recommendations. Crown fixing: Where primary fastenings occur in sheets with profile heights in excess of 20 mm, support crowns of profiles with profile fillers. Seal end laps between plastics profiled sheets with two strips of sealing tape, one along each edge of lap, to prevent future build up of dirt between sheets. Fix liner and outer sheets progressively from one end to avoid distortion. Install spacers and outer sheets immediately after liner sheet installation. Before fixing ensure that surfaces which will be inaccessible are clean. Seal laps of both inner and outer sheets. 11.0 Structural Movement Joints Leave space between Coverworld sheets to coincide with structural movement joints. Fix weather tight movement joint cover to sheets on one side only. 12.0 Fixing Flashings and trims Coverworld Flashings and trims to be lapped at joints as follows, unless specified otherwise. Vertical and sloping flashings/trims: End laps to be the same as for adjacent sheeting. Horizontal flashings/trims: End laps to be 150 mm, sealed and where possible arranged with laps away from the prevailing wind. Where possible fix flashings/trims to structure in conjunction with adjacent Coverworld sheeting. Otherwise fix securely to sheeting.  |
| Twin Skin Metal Profiled Cladding Roof |
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ROOF - minimum pitch 4° 1.0 External Sheet 1.2 External Sheet Finish. External finish to be Dobel 200XT Plastisol in standard colour. Reverse coat grey backing coat. 1.3. External Sheet Fasteners Fasteners to be approved self drilling screws with stainless steel bonded washers 16mm diameter to specification recommended by fixings supplier, with caps to colour match outer sheet. Fasteners to be fixed through profile trough at every pitch at eaves and end laps and at every second profile pitch at intermediate supports. 1.4 External Sheet End Laps. End laps to be a minimum length of 150mm and sealed at each end. Sealant to be 9mm wide by 3mm thick cross linked butyl rubber placed not more than approximately 5mm from the edge of the overlap sheet. 1.5 External Sheet Side Laps. Side laps are to be laid away from the direction of the prevailing wind, where possible. Where this is not possible, or in exposed locations, the side laps are to be sealed with 9mm wide by 3mm thick cross-linked butyl rubber. 1.6 External Sheet Profile Fillers Profile Fillers to be polyethylene foam, tightly fitted under ridge and hip flashings and at eaves. 2.0 Spacers Spacer system to be Coverworld Covergrid System consisting of structural grade galvanised steel bars and bracket supports with thermal break seal pads. Bracket size 60mm - 200mm to accommodate required insulation thickness and 'U' value. 2.2 Spacer Fixings Spacer system to be fixed to purlins with self-drilling screws, (normally two per bracket), minimum length 25mm. 3.0 Thermal Insulation Thermal Insulation to be mineral fibre roll. All edges to be close butted to achieve continuity. Ensure insulation is not compressed between outer and liner sheets. 3.2 Insulation Thickness to be as required to achieve the specified 'U' value. 4.0 Lining Lining to be Coverworld CL20 in hot-dip zinc coated steel, 0.4mm nominal thickness, including alloy coating. 4.2 Lining Finish. Liner coating to be Lining Enamel with bright white internal finish and grey backing coat. 4.3. Lining Fasteners Liner profile to be fixed with self drill screws at every second trough to each support. 4.4 Lining End and Side Laps. End laps to be not less than 40mm long. Side and end laps to be sealed using self-adhesive metalized foil tape. 4.5 Lining Openings All openings cut through the liner panel must be vapour sealed 4.6 Lining Sheet Profile Fillers Profile Fillers to be polyethylene foam, tightly fitted so as to prevent ingress of internal building air into the roof void. 5.0 Flashings and Trims External and Internal flashings and trims to be manufactured from the same material as the Coverworld sheet used adjacently. Flat dimensions exceeding 200mm are to have a bend or stiffener in order to avoid 'oil canning'. 5.2 Flashings Fasteners Flashings and Trims to be fixed at centres not exceeding 300mm using screws or sealed aluminium rivets at 150mm maximum centres. 5.3 Flashings Laps Vertical and sloping flashings are to have the same end lap
detail as the adjacent Coverworld sheeting. Horizontal flashings
should have butt end joints, with the joint covered by a 150mm
butt strap sealed to the flashing at each end. |
Coverworld UK Limited Mansfield Road Bramley Vale Chesterfield Derbyshire S44 5GA
Tel: 01246 858222 Fax: 01246 858223 E-mail: sales@Coverworld.co.uk