B-02 Dead Load — StructuralZero

dead load calculator

build a floor. calculate the weight.

Pick one option per category — the cross-section and total dead load update as you go.

Pick one option per layer — deck, fill, ceiling, MEP, misc
Total dead load (psf) updates as you build the floor assembly

Total DL: 65 psf

Dead load = the weight of everything permanently attached to the building. Calculated, not looked up. Typically 50–80 psf for an office floor system.

Concrete slab (150 pcf × thickness) + steel framing (~8-12 psf) + MEP/ceiling/flooring (~10-15 psf) + partitions (~15-20 psf). Dead load feeds back on itself: heavier members add more dead load.

key concepts

overview Permanent weight calculated from material densities

Dead load is the permanent weight of the structure itself — calculated from material densities and dimensions, not looked up in a table.

the load you can calculate Computed with confidence from unit weights and dimensions

Dead load is the one load you can actually compute with confidence. Weigh the concrete slab (150 pcf × thickness), the steel beams (look up weight per foot in the manual), the MEP systems (~10-15 psf allowance), the ceiling and flooring (~5-10 psf). Add them up. Unlike live load or wind, dead load doesn't change with occupancy or weather — it's there from the day the building opens until the day it comes down.

why it matters more than you think Largest load on most buildings, feeds back on itself

Dead load drives design more than most people realize. It's the largest single load on most buildings. It provides the stabilizing force against overturning and uplift (which is why the 0.9D load combination exists — less dead load is worse when you're checking for wind uplift). And it feeds back on itself: a heavier beam means more dead load, which means you might need an even heavier beam. Getting the dead load right is the foundation of everything else.

unit weights The numbers behind every dead load calculation

NW Concrete

150 pcf

LW Concrete

110 pcf

Structural Steel

490 pcf

Wood Framing

35 pcf

Grouted CMU

135 pcf

Brick (solid)

120 pcf

Steel Deck (1½")

~3 psf

Gypsum Board (⅝")

~4 psf

knowledge check

Dead Load

1. In the dead load calculator, select: Tile + mortar (10 psf), 6" NW slab (75 psf), Steel joists (7 psf), Acoustic tile ceiling (2 psf), and Light MEP (2 psf). What is the total dead load?

84 psf 90 psf 96 psf

2. The eq-panel states a typical office floor system is 50–80 psf. Why is dead load calculated from component weights rather than looked up in a table?

Because dead load depends on the specific materials and dimensions chosen for the project Because building codes prohibit using tabulated dead load values Because dead load varies with occupancy type like live load does

3. Why does dead load "feed back on itself" during design?

Because heavier buildings attract more wind load Because heavier members add more dead load, which may require even heavier members Because dead load increases when live load is applied