18′ – 6×3

Purlins are generally used as horizontally structured beams spanning between trusses to support a roof. Purlins range from

100mm x 75mm (4″ x 3″)  up to 300mm x 100mm (12″ x 4″) and from around 3.6m (12′) long up to 7.315m (24′) long. Timber is supplied in metric sizes.