ASCE 7 Chapter 3 provides unit weights for materials and assemblies used in calculating dead load. Structural steel weighs approximately 490 pounds per cubic foot. Reinforced concrete weighs 145-150 pounds per cubic foot depending on aggregate. Wood members weigh 30-50 pounds per cubic foot depending on species and moisture content. Masonry units weigh 100-150 pounds per cubic foot. Common roofing materials weigh 5-15 pounds per square foot. Ceiling and floor finishes weigh 5-10 pounds per square foot. Mechanical equipment weight must be added based on specific equipment. Fireproofing and insulation add to the structural weight. Dead load calculations use these unit weights multiplied by the volume or area of materials in each structural element.