As for the possibility of the flow of the roof, everything will depend on the professionalism of the actions of workers who will lay the roof. In this case, it is necessary to carry out all measures of subcutaneous waterproofing. If you create a complex roof, then its basis will also be a complex rafter system. The frame is fixed on the Mauerlat, it is based on the connection of puffs, rafters, struts, racks and crossbars. As a rule, the whole system is a lot of triangles from boards and timber. The most exquisite is the roof with several turrets. The appearance is excellent, but work in the roof should be invested a lot. It is better not to take cement-sand and natural tiles, since it does not fit the main properties.