The weight of structural steel in a structure or module is the total mass in kilograms or pounds of all the steel in its load-bearing, wind-resisting, and form-giving skeletal framework. This does not include steel used in curtain walls, non-integral floorplates, or rebar used in reinforced concrete. It does include any concrete-encased structural steel beams when such a system is used. This includes elements both above ground and below ground, including the foundations.

A material quantity taken from a bill of quantities or structural drawings may describe specified work. The source should distinguish that quantity from one established for completed work.

The material counts only where it does structural work. Reinforcement in a non-structural screed, cladding hung on a frame and decorative timber are outside these fields even though they are the same material.

Where a structure was extended or partly rebuilt, the figure belongs to whichever scope the source measured. A weight for the original building and one for the building today are different numbers.