Building loads are traditionally divided into two large groups: Dead loads which act for the entire life of the building, and Live loads, which act for a shorter period of time.
Dead loads are the weight of the structure itself, including interior partitions, plus any permanent, built-in equipment, structure or finish, including plumbing fixtures and sprinkler piping, electrical, HVAC equipment.
Dead load numbers might also include allowance for likely future additions (roof top solar panels, deck hot tub, etc).
Approximate MINIMUM material dead loads include:
Framing: 2x8 - 16 inch o.c. 2 psf
2x12 - 16 inch o.c. 3 psf
1/2 inch gypsum board: 2 psf
1 inch hardwood flooring: 4 psf
1/2 inch plywood: 2 psf
Built up roof: 7 psf
Asphalt shingles: 2 - 3 psf
Wood shingles: 3 psf
Slate roofing: 10 psf
Tile roofing: 15 psf
Add up all the components that make up the structure for the total dead load.
For light construction for example, asphalt shingle roof, on 1/2 plywood, on 2x8 framing, with gypsum wallboard ceiling would have a dead load of approximately 9 psf. Add insulation and 10 psf might be a reasonable MINIMUM dead load.
