Dead Load Calculator
Look up typical dead load (self-weight) in pounds per square foot for common building assemblies — roofing, framing, and flooring.
How this calculator works
Every part of a building has weight just from existing — the shingles on the roof, the joists under the floor, the drywall on the ceiling. That permanent, built-in weight is called dead load, and it’s different from live load, which covers people and furniture that come and go.
Because dead load is really just the sum of real material weights, this calculator doesn’t compute it from a formula. Instead it looks up a typical dead load per square foot for common assemblies, pulled from a standard reference.
Formula: This calculator looks up a typical dead load (self-weight) per square foot by assembly type from a standard reference — it does not calculate from a formula, since dead load is the sum of fixed material weights, which vary by product.
Worked example
Assembly: asphalt shingle roof
- Typical dead load = 3 psf
Reference
Typical assembly dead loads
| Assembly | Dead load |
|---|---|
| Asphalt shingle roof | 3 psf |
| Wood-frame floor (joists + subfloor) | 10 psf |
| Concrete slab (per inch of thickness) | 12.5 psf per inch |
| Drywall ceiling | 2 psf |
| Metal roofing | 1.5 psf |
How to use
Select the assembly type closest to what you’re planning — roofing, framing, or flooring — and the calculator returns its typical dead load in pounds per square foot. For a full assembly with multiple layers (say, framing plus subfloor plus finish flooring), add the relevant figures together for a combined estimate.
These are commonly cited planning figures for typical assemblies, not a substitute for summing your actual specified materials. A licensed structural engineer calculates exact dead load from the real assembly for anything load-bearing.
Frequently asked questions
What is dead load?
Dead load is the permanent, fixed weight of a building's own construction — framing, roofing, drywall, flooring, and other materials that don't change over time. It's distinct from live load, which covers people, furniture, and other weight that comes and goes. Structural design adds dead load and live load together to size members.
Why is this a lookup instead of a formula?
Dead load is the sum of the actual weights of every material in an assembly, and those weights vary by product and manufacturer. Rather than calculate from scratch, this tool references commonly cited planning figures for typical assemblies, which is a faster starting point for early estimates than sourcing every material spec sheet.
Why does concrete slab dead load depend on thickness?
Concrete is a solid, uniform material, so its weight scales directly with how much of it there is — thicker slabs simply contain more concrete per square foot. That's why concrete slab dead load is given per inch of thickness rather than as a single flat number, unlike an assembly like a shingle roof with a fixed makeup.
How do I use dead load once I have it?
Dead load is combined with live load (occupants, furniture, snow, and similar variable weight) to get the total load a structural member must carry. Beams, joists, and footings are then sized to that combined total. Dead load alone doesn't tell you if a member is adequately sized — it's one input into that larger calculation.
Estimates only. Verify quantities with your supplier before purchasing.