The size and shape of your building are determined by several factors. Foremost are the needs of your business. It may be that the height and width of the doorways are critical, it may be that there are minimum dimensions required by legislation (e.g. for MOT bays). In many cases the shape and size of the plot available will determine the building’s dimensions.

It is usually most cost-effective to minimise the span and eaves height of the building – increasing either of these has a disproportionate effect on the cost of the steel frame; equally buildings that are very tall and narrow will be expensive, as the wall area is large in relation lo the floor area. The most economical cost per square metre (floor area) is usually achieved by designing a rectangular building whose length is between 1.5 and 2 limes it’s width (span) and whose height is between 4m and 5.5m. Buildings which are oddly shaped (i.e. L-shaped or T-shaped) will incur significant extra cost. All buildings should be designed on a flat, level base.

The most cost-effective roof is symmetrical, with a central ridge. Offset ridges and monoslope designs again incur significant extra costs.