Before deciding on a full repaint of a metal roof, check whether the problem is merely dirt and natural ageing rather than damage to the coating. From the ground, dust, chimney deposits and a change in paint colour can look similar, so assess the cause up close by comparing a sheltered section with one exposed to the sun. Pay attention to the eaves line, ridge caps and side flashings, as well as to tightness and fixing. If the coating is continuous, cleaning matched to the paint may be enough. Leave local repair to the judgement of the renovation contractor.

Choosing a metal roof for a company building starts with describing how the interior will be used, not with comparing materials. Check the heating, humidity, number of employees and type of stored materials, because an unheated warehouse has different needs from a workshop, shop or hall with a wet process. Tell the designer if you plan to change the building's function, since later insulation may require rebuilding details. The choice should cover the roof, walls and ventilation, not just the covering.

The choice between a gable window, a roof window and a dormer depends on where light is actually needed in the attic. First draw the room functions and furniture layout, because a desk needs different light from stairs or the area by the bed. Check the cardinal directions and the surroundings of the house, which may restrict daylight. Also consider the sloped ceilings and the height of the knee wall to assess the view from a seated position. Compare the full scopes of work: structure, flashings, insulation and finishing.