Tiled Roof

The shape and strength of the Multibeam section is eminently suitable to sustain the greater loadings imposed by a tiled roof. However, due to the nature of the forces imposed upon the purlin sections by this form of roof construction, additional considerations are required in the design of the purlin and its restraint system.


Angle Strut Anti-Sag System
The angle strut brace system caters for the downslope force produced in the roof from dead and superimposed loads. Slope length is limited by the load on diagonal ties.
The section capacitities are based on using an anti sag system with restraints at a minimum of 1/3 points and a minimum angle of 30 deg on the screwed rods – Table 1.4 shows the max spans achievable for this combination with the c/c of purlins shown – where the span is curtailed by the minimum 30deg angle of the screwed rods place the restraints at 1/4 points as shown in table 1.4 One set of diagonals are required for every 6.0m length of roof slope as long as this is complied with the roof slope can be any length. Stiffened cleats should also be used with tiled roof construction.

Anti-Sag Requirements with metal liner

When certain cassette metal liner profiles are fixed to the purlin top flange enough restraint may be provided in order to use the standard load tables in conjunction with the anti-sag system. For further advice please contact our Technical Department.