Live load
Live load is the variable imposed load from occupants, furniture and use, set by AS/NZS 1170.1 and combined with dead and wind loads in design. Also called imposed load.
Ask Chalkline about this →Live load is the variable imposed load on a structure from occupants, furniture, stored goods, and use. It is set by AS/NZS 1170.1 and combined with dead and environmental (wind, snow) loads in the design. It is also called the imposed load.
The defining feature is that a live load is variable: it changes with how the building is used and can move around or be removed entirely. AS/NZS 1170.1 sets standard imposed-load values per use, for example a residential floor is designed for a uniformly distributed load plus a concentrated load, with higher values for assembly areas, balconies, and storage, because those see heavier or more crowded use.
The contrast with dead load is the key: dead load is the fixed self-weight of the building; live load is the changeable load of using it. The engineer combines them (with load factors) in load cases to find the worst realistic demand on each member.
For a builder the practical point is that the design live load reflects an intended use, so a change of use can break the assumption. Turning a domestic garage or a Class 1 room into storage, a workshop with heavy plant, a gym, or an assembly space can impose far higher live loads than the floor was designed for. Mezzanines and balconies are common trouble spots. If the use is changing to something heavier or more crowded, get the structure checked against the right imposed load rather than assuming the existing floor will carry it.
Also known as: Imposed load, variable action.
Category: Structure / Loads.
Related
See also
References
- AS/NZS 1170.1 Structural design actions, Standards Australia (verified 2026-06-01)
Last updated: 2026-06-01. Verified: 2026-06-01. Quarterly review for currency.