The key decision before accepting a metal roof is whether the inspection will cover layers that will soon disappear beneath the covering. It is worth checking the geometry of the substrate, the batten spacing, the method of fixing, the condition of the coating, the continuity of ventilation and the routes for water drainage. Most problems stem from faults that are visible before work is completed, so photographs and stage-by-stage inspections offer more than a view of the finished slope from the ground. Documentation of the stages helps catch errors before correcting them becomes expensive.