1. A pitched roof is a sloping roof with defined technical terms like trusses, battens, cleats, eaves, gable, hip, pitch, purlins, common rafters, and principal rafters. 2. Pitched roofs are classified into single roofs like lean-to, couple, couple-close, collar beam, and collar and scissors roofs. They are used for spans up to 2.4m. 3. Double or purlin roofs use purlins for spans over 2.4m. Trussed roofs use triangular frameworks to support the roof over longer spans.