Abstract: One aspect of the invention is concerned with a support member for use in supporting cladding sheets. The support member includes a timber length capped by a metallic rail carrying spaced cleats. The cleats are deformable to grip the edges of cladding sheets laid over the support member, and the rail is connected to the timber over its entire length, so reinforcing the timber length. Other aspects of the invention are concerned with roof trusses in which such support members form the top chords, and with cladding systems in which the support members are used.