floorloading

Floor loading is the design load that a floor system is intended to carry. It is usually expressed in pounds per square foot (psf) or kilonewtons per square meter (kN/m^2). Floor loads comprise dead load, the weight of the structure and permanent finishes, and live load, the weight of occupants, furniture, equipment, and other movable loads. In some contexts, dynamic effects or impact loads may also be considered.

Structural capacity depends on components such as joists, beams, and slabs, which determine how much load can be carried and how much the floor can deflect under load. Floors must accommodate both uniform loads and concentrated loads, and design must account for deflection, vibration, and long-term performance.

Building codes specify minimum live loads by occupancy. Typical residential floors are designed for around 40 psf, while office spaces often require about 50 psf. Storage or industrial areas may be designed for substantially higher loads, sometimes in the range of 100–250 psf or more, depending on use. Floors that carry pallet racks, heavy machinery, or other concentrated loads require careful engineering to ensure local areas and overall structural performance.

In design and retrofit work, a structural engineer evaluates floor loading and may reinforce floors with thicker slabs, additional framing, or overlays. Practical considerations include floor flatness and subfloor condition, as weaknesses or settlement can limit load capacity and affect safety and serviceability.