In Plain English
Quick Answer
The weight of people, furniture, snow, and other movable items that a building must support.
Definition
Definition
A variable, movable load on a structure caused by the occupants, furniture, vehicles, equipment, snow, or other non-permanent items. Live loads can change in magnitude and position over time and are specified by building codes based on occupancy type. Structural members must be designed to carry both dead loads and the maximum anticipated live loads.
Context
Why It Matters in Bidding
Live-load values drive structural member sizing, which directly affects quantities of concrete, rebar, steel, and framing an estimator carries. When an owner specifies heavier-than-code live loads for storage, assembly, or equipment areas, member sizes and costs climb, so bidders must read the structural notes carefully rather than assume baseline occupancy loads.
Example
Example
Pricing a warehouse mezzanine, an estimator notes the structural drawings call for a 125 psf live load instead of typical office loading, which upsizes the steel beams and increases the framing tonnage carried in the bid.
See Also
Related Terms
FAQ
Questions Contractors Ask
What is the difference between live load and dead load?
Dead load is the permanent, fixed weight of the structure itself, such as framing, slabs, and roofing. Live load is the variable weight of occupants, furniture, vehicles, and snow that changes over time. Members must be designed for the combination, and code-specified live loads vary by the building's occupancy type.
Why does live load matter when pricing a structural bid?
Live load determines member sizes, which set quantities of steel, concrete, and reinforcing. Higher specified live loads for storage, assembly, or industrial areas increase tonnage and rebar, raising both material and erection costs. Estimators should verify load notes on the structural drawings before taking off framing.
Who determines the live loads for a building?
The structural engineer of record sets design live loads using the governing building code minimums for each occupancy, sometimes increased by the owner for special equipment or future flexibility. These values appear in the general structural notes, which estimators and detailers should review before quantifying members.
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