Total useful floor area TUFA

The area of a building can be measured in a number of different ways, and it is very important to be clear about which measure is being used, for example in property sales, planning applications, building regulations applications, lease negotiations, rating valuations and so on.

The term 'total useful floor area' (TUFA), or 'total usable floor area' is described in part L of the building regulations as:

'...the total area of all enclosed spaces measured to the internal face of the external walls. In this convention:

• The area of sloping surfaces such as staircases, galleries, raked auditoria and tiered terraces should be taken as their area on plan.
• Areas that are not enclosed such as open floors, covered ways and balconies are excluded.'

It suggests that is equivalent to the 'gross floor area' as measured in accordance with the guidance issued to surveyors by the Royal Institution of Chartered Surveyors (RICS).

This refers to the precise definitions for the accurate measurement of buildings set out in the RICS Code of Measuring Practice. However, the term 'gross floor area' is more correctly described as 'gross internal area', which describes the enclosed area of a building within the external walls taking each floor into account but excluding the thickness of the external walls. This is distinct from the 'gross external areal' which describes the whole area of the building, including external walls.

For more information, see Gross internal area.

[edit] Related articles on Designing Buildings Wiki

• Conversion of material volumes.
• Employment density ratio.
• Gross external area.
• Gross internal area.
• Gross site area.
• Net internal area.
• Beneficial occupation.
• Case notes for rating valuation.
• Choice of method for rating valuation.
• Floor area ratio.
• Gross development area.
• International Property Measurement Standards.
• Measurement of existing buildings.
• Occupant capacity of a building or space.
• Profits method of rating valuation.
• Rating valuation.
• Rental method of rating valuation.
• Statutory formulae for rating valuation.