Steel Buildings in Europe

Part 2: Concept Design 2 - 10 Table 1.4 Typical weights of roofing materials Material Weight (kN/m 2 ) Steel roof sheeting (single skin) 0,07 – 0,12 Aluminium roof sheeting (single skin) 0,04 Insulation (boards, per 25 mm thickness) 0,07 Insulation (glass fibre, per 100 mm thickness) 0,01 Liner trays (0,4 mm – 0,7 mm thickness) 0,04 – 0,07 Composite panels (40 mm – 100 mm thickness) 0,1 – 0,15 Steel purlins (distributed over the roof area) 0,03 Steel decking 0,2 Three layers of felt with chippings 0,29 Slates 0,4 – 0,5 Tiling (clay or plain concrete tiles ) 0,6 – 0,8 Tiling (concrete interlocking) 0,5 – 0,8 Timber battens 0,1 Variable actions Variable actions should be determined from the following Eurocode parts: EN 1991-1-1 for imposed roof loads EN 1991-1-3 for snow loads EN 1991-1-4 for wind actions EN 1991-1-1 recommends a uniform load of 0,4 kN/m 2 for roofs not accessible except for normal maintenance and repair (category H). A point load of 1,0 kN is also recommended, but this will only affect the design of the sheeting and not the main structural elements. EN 1991-1-3 includes several possible load cases due to snow, including uniform snow and drifted snow, which typically occurs in valleys, behind parapets etc. There is also the possibility of exceptional snow loads. The value of the snow load depends on the building’s location and height above sea level. EN 1991-1-4 is used to determine wind actions, which depend on altitude, distance from the sea and the surrounding terrain. The determination of loads is covered in detail in a separate chapter of this guidance. Loading due to services will vary greatly, depending on the use of the building. A typical service loading may be between 0,1 and 0,25 kN/m 2 as measured on plan, depending on the use of the building. If air handling units or other significant equipment loading is to be supported, the service load should be calculated accurately. 1.4.2 Temperature effects In theory, steel frames expand and contract with changes in temperature. Often, the temperature change of the steelwork itself is much lower than any change