The choice of rafters is determined primarily by the structural design, not by the price of timber alone. Before ordering, you need to know the cross-sections, lengths and number of elements, as well as the required timber class and how it is to be prepared. Take account of the roof geometry and support layout, since corners or openings may call for different elements. When comparing offers, check that they cover the same scope of processing, transport and connections. Remember that a cheaper cubic metre does not always produce a cheaper finished roof structure.

Roof ladders and chimney steps form a defined access route to the chimney, flashings and rooftop equipment, making them easier to inspect without walking over random areas of the covering. When planning, the first thing to establish is whether these elements are intended solely for movement or also as an anchor point for fall-protection equipment — this determines the choice of system. A step offers a small surface for the foot, while a roof ladder gives a wider platform at the chimney or at equipment requiring attention. Both should form a logical sequence, since a single platform without access can prove of little use.