Before ordering a new roof covering, establish what lies beneath the existing one and whether the structure is ready for replacement. This guide sets out how to assess the old substrate, plan the stages of stripping and prepare the area around the building. Check records of earlier repairs, the condition of the roof frame and how moisture is managed, since replacing the visible layer alone does not always solve the problem. You will also learn how to match the support to the sheeting and limit damage during installation. Leave design decisions to the specialist.

The roof shape should be chosen mainly for how the loft will be used and how simple the details will be, not for the name of the form alone. It is worth checking how many slopes, hips and valleys the planned footprint will create, and how that affects flashings and drainage. A simple duo-pitch roof makes the water flow easier to read and the sheets easier to lay out, while a more complex geometry demands more careful drawings. The final choice of covering and layers should be left to the designer, as angles, supports and details decide it.