lattiatason

Lattiatason, in architectural and construction contexts, refers to the floor level—the horizontal plane forming the bottom boundary of a space. It acts as the reference surface for design, measurement, and installation of finishes, fixtures, and services. In construction drawings and BIM models, lattiatason is used to define the nominal height of floors and to indicate transitions between spaces.

In practice, lattiatason is established from a datum point or reference height and can vary between rooms or structural slabs. Finishes such as tiles, hardwood, or carpet add thickness to the base, while subflooring and underfloor systems influence the final height. Differences in lattiatason between adjoining spaces may require floor transitions, thresholds, or ramps to maintain usability and accessibility. Aligning floor levels is also important for plumbing layouts, door clearances, and HVAC equipment.

The term comes from the Finnish words lattia (floor) and taso (level). In Finnish construction language the genitive form lattiatason is used in phrases describing the height or condition of the floor level, for example lattiatason korkeus or lattiatason säädöt. See also: kattotaso (ceiling level), lattiapinta (floor surface), floor plan, and floor finishing.