Guide: development measures
GFA, built-up and leasable area: specify the measurement basis
A development brief can carry several area figures for one building: gross floor area, built-up area, leasable area, net internal area. They look comparable because they share a unit, but each is measured to a different boundary, for a different purpose, with different spaces counted. This guide explains why the figures differ, what an area schedule should state about each one, and why no single factor turns one into another. The physical decisions behind the numbers are covered under commercial building development.
Area labels need a stated measurement basis
One building can honestly carry several area figures, because each answers a different question. A planning authority wants to know how much floor area is being built on a plot. An owner registering units wants to know the extent of each unit. An occupier wants to know how much space it can actually use. Each question draws the line around a different part of the building, so the figures differ even when every one of them is correct.
The labels do not settle the matter on their own. Gross floor area has published official definitions, but built-up area and leasable area are used in different ways by different parties, and neither carries one universal meaning. The difference between gross floor area and built-up area in a given document lies in how each was measured, not in the names. A figure is only comparable with another when both state the method used to measure them, the edition of that method and the purpose of the measurement. Without that, two schedules for the same building can disagree and both be right, or agree and both be misleading.
Boundary, included spaces and purpose
Three things define any area figure: the boundary it is measured to, the spaces it includes or leaves out, and the purpose it serves. One official illustration is section 603.02 of the Department of Municipalities and Transport's land use and development conditions for Al Ain City, published in Arabic. It measures gross floor area from the outer face of the external walls and sums the horizontal area of every floor. It counts, among other things, the stairwell on each floor, storage and plant areas, spaces under a concrete roof with a height of 2.1 metres or more and balconies roofed and walled on three sides, and it leaves out, among other things, permanently open areas, parking below ground-floor level and covered roof areas within a stated limit. It is Al Ain's definition for its own development conditions, cited to show how a measurement is specified, not as every municipality's current rule.
Purpose also appears in Abu Dhabi's real estate legislation. Administrative Decision No. 233 of 2015 adopted a unified mechanism for measuring and calculating the areas of buildings, villas and real estate units in the emirate, set out in an annex to the decision. The decision's main text says the mechanism is meant to be used across real estate work, including ownership plans, architectural plans, financing, valuation, sale and rent, and requires an application for an area calculation to state the purpose of the calculation. The annex itself is not summarised here.
DMT reports the development it approves in square metres of gross floor area.
A named reference shows why methods differ
Professional measurement codes make the same point from another direction. The Royal Institution of Chartered Surveyors' Code of measuring practice, 6th edition (May 2015), defines gross external area as the area of a building measured externally at each floor level, gross internal area as the area measured to the internal face of the perimeter walls at each floor level, and net internal area as the usable area within the building measured to the internal face of the perimeter walls.
A short example shows how much the boundary matters. The thickness of the perimeter walls is included in gross external area and excluded from gross internal area, so the same floor yields two different gross figures under one code. Net internal area then sets aside spaces the gross measures include, such as stairwells, lift wells, toilets and permanent circulation.
The code is cited here as a named, published example of method dependence. It is not a statement of current mandatory practice in the UAE, and its terms should not be read as equivalents of gross floor area, built-up area, gross leasable area or net leasable area in an Abu Dhabi document. Each document's own definition governs its own figure.
What to ask for in a development area schedule
An area schedule should let anyone reading it see how each figure was produced. The items below are questions to put to whoever prepares the schedule; they are not presented as mandatory statutory fields.
Label and purpose
What is each figure called, and what is it for: a planning submission, unit registration, a lease, a sale contract or a valuation?
Method and edition
Which definition or code was used to measure it, in which edition, and is that the method the intended use requires?
Measured boundary
Is the area taken to the outer face of the external walls, the internal face, the centre line of shared walls or some other line?
Common, service and parking areas
How are cores, corridors, plant rooms, shared amenities and parking treated: included, excluded or apportioned?
Source drawing and date
Which drawings, at which revision and date, were measured, and do all the figures in the schedule come from the same set?
Keep area measurement separate from FAR and plot coverage
A measurement basis says how an area is counted; a ratio says how that area relates to the land. Floor area ratio and plot coverage each rely on a defined measurement, and a figure prepared for a lease or a sale cannot simply be dropped into a planning ratio. How the two ratios work is explained in Floor area ratio and plot coverage: two different development measures.
The same caution answers the question of conversion. Built-up area cannot be turned into leasable area with one fixed factor. The relationship depends on the methods used for each figure, on what each counts, and on the building itself: its core layout, circulation, plant and parking. Two buildings with the same built-up area can offer quite different leasable areas. The reliable route is to measure both on stated bases from the same drawings.
For a development brief, that means agreeing the area schedule and its measurement bases before asset options are compared. The schedule is where the decisions about use and site described under building development are first expressed in numbers.
Comparing building options?
Tell us about the site, the building you have in mind and the area figures you have been given. We can discuss agreeing an area schedule and measurement basis as part of the development brief.
Discuss a building brief