Cladding & Fixings specialists in Grantham, Lincolnshire also Cardiff, Wales & Wolverhampton, West Midlands

DESIGN & PERFORMANCE REQUIREMENTS FOR METAL CLADDING


1.0 DESIGN

Complete the design of the Cladding Supplies in accordance with BS5427 Part 1 and the requirements of the Cladding Supplies 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:

3.1 Wind load Span/150

3.2 Dead and Imposed load Span/200

3.3 Dead Load Span/500

4.0 'U' value calculation.

The U value requirement is to be determined by Building Regulations, approved Document 'L'. Uniclad twin skin, (built-up), systems will comply using Unigrid 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

Cladding Supplies steel sheeting is non combustible and will not contribute to a fire. Cladding Supplies coated steel sheeting achieves the following;

BS 476 Part 3 (External Roofing) Class SAA
BS 476 Part 5 (Ignitability) P - not easily ignitable
BS 476 Part 6 (Fire Propagation) Passed
BS 476 Part 7 (Surface Spread of Flame) Class 1

Cladding Supplies coated steel sheeting achieves a Class 0 rating in the Building Regulations.

6.0 Materials

Cladding Supplies steel sheeting is profiled from alloy coated flat steel sheet manufactured to EN 10147:1992.

7.0 Finishes

Cladding Supplies steel sheeting has a reverse coat of grey polyester. The exposed face is supplied in one of the following finishes:
Plastisol: 200-micron external grade PVC coating.
PVf2:27-micron thick Polyvinyl Flouride coating.
Polyester.
Lining Enamel.

8.0 Colour

A full colour range for each coating type is available as detailed in data published by Cladding Supplies. Lighter colours are recommended for roofing.

9.0 Fixing of Sheeting

For Cladding Supplies 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 Cladding Supplies sheets with exposed joints of side laps away from prevailing wind unless shown otherwise on drawings. Cut openings in Uniclad 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 Cladding Supplies 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 specialized tools recommended by the fastener manufacturer. When used, screw-guns must be fitted with depth sensitive devices and used at the correct speed. Protect Cladding Supplies 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 plastic 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 Cladding Supplies 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.

Cladding Supplies 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 Uniclad sheeting. Otherwise fix securely to sheeting.
 
 

SPECIFICATION - TWIN SKIN PROFILED METAL CLADDING

ROOF, Minimum pitch 4 degrees

1.0 EXTERNAL SHEET

1.1 External Sheet Specification

External Sheet to be CSL 32R undefined undefined undefined undefined undefined undefined profile in Aluzink coated steel to 0.70mm nominal thickness, including alloy coating.

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

2.1 Spacer Specification

Spacer system to be CSL spacer bar 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

3.1 Insulation Specification

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

4.1 Lining Specification

Lining to be CSL 19/1000 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 mast 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

5.1 Flashings Specification.

External and Internal flashings and trims to be manufactured from the same material as the CSL 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 CSL sheeting. Horizontal flashings should have butt end joints, with the joint covered by a 150mm butt strap sealed to the flashing at each end.
 

SPECIFICATION, TWIN SKIN METAL PROFILED CLADDING

VERTICAL CLADDING

1.0 EXTERNAL SHEET

1.1 External Sheet Specification

External Sheet to be CSL 32W undefined undefined undefined undefined undefined undefined profile in Aluzink coated steel to 0.55mm nominal thickness, including alloy coating.

1.2 External Sheet Finish.

External finish to be Dobel 200XT Plastisol in standard colour. Reverse coat grey backing coat. Alternative external finish Pvf2

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.

Laps to be a minimum length of 100mm.

1.5 Profile Fillers.

Profile Fillers to be polyethylene, tightly fitted behind flashings.

2.0 SPACER SYSTEM.

2.1 Spacer Specification.

Spacer system to be CSL spacer 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.

3.1 Insulation Specification.

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

4.1 Lining Specification.

Lining to be CSL 19/1000 in hot-dip zinc coated steel, 0.40mm 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.

4.5 Lining Sheet Profile Fillers.

Profile Fillers to be polyethylene foam, tightly fitted so as to prevent ingress of internal building air.

 

5.0 FLASHINGS AND TRIMS

5.1 Flashings Specification.

External and Internal flashings and trims to be manufactured from the some material as the CSL 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 of 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 CSL sheeting. Horizontal flashings should hove butt end joints, with the joint covered by a 150mm butt strap sealed to the flashing at each end.