ABSTRACT
The traditional alternative to the batten roll method is to use standing seams. Transverse joints, ie across the fall of the roof are made with single or double welts (Figs 4 & 5). Single welts should only be used for roofs having a pitch greater than 40 deg and for aprons, cappings etc. Welted transverse joints should be fixed with two clips evenly spaced in each bay on roofs where the pitch is 20 deg or less. The double lock cross welts should be sealed by coating the edges with boiled linseed oil before forming the welt. Seams and cross welts are secured by aluminium clips (Fig 4).
