Usable floor area is an essential spatial attribute of buildings and premises. This information is widely used. Usable floor area should therefore be specified in a reliable and possibly unambiguous manner. An important factor determining its correct calculation is adopting a proper methodology of quantity surveying.
This paper comprises further analysis undertaken by authors on the issue of determining usable floor area. Quantity survey principles specified in the applicable laws and the relevant Polish Standards were discussed and then compared. The considerations were supported by practical examples. The authors also referred to the case-law of the administrative courts and pointed to the doubts which most frequently arise during the quantity surveying of usable floor area. The problem of voluntary application of Polish Standards was analyzed as well.