How to do a building take-off: the step-by-step method

This guide follows French practice: French standards (NF DTU), French regulations and French bill conventions. Most sources are in French.

What a take-off is for

A take-off is the calculation of the quantities of a piece of work from its dimensions: linear metres of skirting, square metres of partition, cubic metres of concrete, sockets counted one by one. It gives no price: it says how much. French training frameworks distinguish two moments. The preliminary take-off (avant-métré) is work on drawings, before construction; the take-off in the strict sense (métré) deals with work actually carried out.

For the architect or the quantity surveyor, the preliminary take-off is used to estimate the project. A 2004 ministerial answer pointed out that design-stage studies include a forecast cost broken down by trade, based on a preliminary take-off.
In a contractor's office, it is used to answer a tender: working out the quantities, or checking those of the form provided.
During construction, the as-built take-off records what has actually been built, for measurement records, interim valuations and the final account.

The quotation comes next: each quantity multiplied by a unit rate, itself taken from a rate build-up (labour, materials, plant). A good rate applied to a wrong quantity gives a wrong quotation.

Lump sum or unit rates: what the quantity commits you to

The form of the contract prices determines who bears a quantity error. It is the first thing to look for.

Global lump-sum price. The contractor fills in a DPGF (décomposition du prix global et forfaitaire, the breakdown of the lump-sum price) and commits to a price whatever the quantities actually carried out: in principle, it cannot claim extra because there turned out to be more square metres than expected. When the designer supplies the quantities, the ministerial answer quoted above states that contractors must check them when submitting their tender.
Unit rates. The schedule of unit rates (BPU) sets a price per unit, applied to the quantities actually carried out. The estimated bill of quantities (DQE) multiplies these rates by estimated quantities to compare tenders; in principle it is not contractual. It is then the as-built take-off that gets invoiced.

The documents to gather

A take-off is rarely done from a single drawing. Before measuring, gather the file and note what each document brings; the acronyms are explained in the take-off glossary.

What to look for in each tender document
Document	What to look for
Floor plans, site plan	Lengths, areas, items to count, room names
Sections, elevations, details	Heights, thicknesses, pitches
CCTP (particular technical specification)	The description of each item, what its price includes, its method of measurement
DPGF form or breakdown form	The list of items, their order, their code and their unit
BPU (schedule of unit rates)	The definition of each unit rate and its unit
DQE (estimated bill of quantities)	The estimated quantities, to complete or check
Schedules	Doors and windows, fittings and equipment to count

Note the revision of each drawing used: when revision B replaces revision A, it is the only way to know which quantities to revisit.

The step-by-step method

1. Read the specification before the drawing

The CCTP describes each item and often its rule of measurement: “per m² actually installed”, for instance, in the drylining specification of a French vocational exam paper (CAP). It also says what the price includes: in that same specification, service ducts are included in the partition item, so they are not counted a second time.

2. Break down into elementary items

Each line of the take-off corresponds to an item with a single price: same material, same thickness, same installation. The DPGF form gives this breakdown. Failing that, start from the broad families taught in French training (site adaptation, load-bearing structure, envelope, interior fit-out, building services, finishes, final finishing) and work down to an item that can be priced.

3. Set a measuring order

Floor by floor, room by room or grid line by grid line, always in the same direction: no room is forgotten, none is counted twice, and a colleague can follow the calculation.

4. Write down conventions and assumptions

At the head of the take-off: the measuring line (centre line or finished face), the heights used, the threshold for deducting openings, the rounding rule. Then each assumption: a missing dimension worked out from other dimensions, a contradiction between the drawing and the specification, a question put to the designer. A written assumption can be corrected; a forgotten one becomes a mistake.

5. Measure and write out every calculation

Location, dimensions, operation, result: each line must be repeatable on a calculator, and deductions are written as negative lines. Follow the codes and the order of the form, and mark on the drawing what has been counted. The framework of the French BTS in construction economics expects calculation details “usable by all other colleagues” and location drawings. Presentation has a guide of its own: take-off calculations.

6. Cross-check

The same framework requires quantities that are “checked, self-checked”, with their orders of magnitude verified. In practice: the floor finishes of a level must add up to the area of its rooms; the length of skirting, to the perimeter of the rooms minus the door openings; the number of doors, to the door schedule. A difference is not necessarily a mistake, but it must be explained.

Units

The unit of an item is the one in the form or the schedule of rates, not the one that suits you: skirting paid per linear metre is not returned in square metres.

Common take-off units
Unit	For	Examples
ml	Length (linear metre)	Skirting, angle beads, pipe runs, kerbs
m²	Area	Partitions, render, floor and wall finishes, roofing
m³	Volume	Concrete, earthworks, backfill
u	Items counted one by one	Doors, sanitary fittings, sockets, inspection chambers
kg or t	Items measured by weight	Reinforcement, structural steelwork
ens or ft	Item paid as a single sum (set, lump sum)	Site set-up, testing

Worked example

A living room of 6.00 × 4.50 m and a bedroom of 3.60 × 3.20 m, measured to the finished inside face, under a 2.50 m ceiling. The living room has a 0.90 × 2.10 m front door and a 1.80 × 1.25 m window; the bedroom has a 0.80 × 2.10 m door opening onto the living room and a 1.20 × 1.25 m window. The specification, taken for the example, requires all openings to be deducted. Seven items, from four trades:

Take-off of the living room and the bedroom
Item	Location and calculation	Quantity
Floor tiling	Living room: 6.00 × 4.50	27.00 m²
Wood flooring	Bedroom: 3.60 × 3.20	11.52 m²
Tiled skirting	Living room: 2 × (6.00 + 4.50) − 0.90 − 0.80	19.30 ml
Timber skirting	Bedroom: 2 × (3.60 + 3.20) − 0.80	12.80 ml
Wall painting	Living room: 21.00 × 2.50 − 0.90 × 2.10 − 0.80 × 2.10 − 1.80 × 1.25 = 52.50 − 1.89 − 1.68 − 2.25	46.68 m²
	Bedroom: 13.60 × 2.50 − 0.80 × 2.10 − 1.20 × 1.25 = 34.00 − 1.68 − 1.50	30.82 m²
	Total wall painting	77.50 m²
Ceiling painting	Living room 27.00 + bedroom 11.52	38.52 m²
Sockets	Living room 5 + bedroom 3	8 u

The bedroom door is deducted twice, once on each side: painting is counted face by face, like skirting. The cross-checks hold:

floors: 27.00 + 11.52 = 38.52 m², the ceiling area;
skirting: 19.30 + 12.80 = 32.10 ml, that is the perimeters 21.00 + 13.60 = 34.60 ml minus the door openings 0.90 + 0.80 + 0.80 = 2.50 ml;
painting: 34.60 × 2.50 = 86.50 m² gross, minus the openings 1.89 + 1.68 + 2.25 + 1.68 + 1.50 = 9.00 m², gives 77.50 m².

If the contract set a threshold of 2.00 m² per opening below which voids are not deducted (taken for the example), only the living room window, 2.25 m², would be deducted: painting would rise to 86.50 − 2.25 = 84.25 m², 6.75 m² more for the same drawing.

The most common mistakes

Measuring before reading the specification, then redoing everything on discovering the method of measurement.
A unit different from the one in the form, or two items with different prices in the same line.
An item counted in two trade packages, for want of reading the scope boundaries.
DPGF quantities copied without checking, when the price is a lump sum.
A scale never checked against a dimension, on a PDF printed “fit to page”.
Dimensions rounded before calculating, or totals that are not the sum of the lines written.
No assumptions noted, no drawing revision: impossible to update the take-off when the project changes.

Doing it in Kotelys

Kotelys is used for step 5, measuring and writing out every calculation, on the PDF drawings or images (scans, screenshots) of the file.

The scale is set drawing by drawing; a scale written on a PDF is offered as “read on the drawing”, and “Check the scale on a dimension of the drawing” detects a PDF shrunk when it was printed.
Each item of the form becomes a type: a name, a colour on the drawing, a total. It is drawn with Length (ml), Area (m²) or Count (u); a height given to the type produces a wall area, a thickness a volume.
Deductions and openings are placed on the shape; “Openings not deducted below … m²” applies your contract's rule for voids not deducted.
Zones split the drawing by flat or by floor, and the “Break down by zone” box of the reports gives the quantities location by location.
The Reports tab produces the quantity summary, the take-off calculations (every calculation written out) and an Excel workbook; each total is the sum of the lines shown.

Kotelys does not read the specification and does not recognise items by itself: you click what you count, and the breakdown, the conventions and the checks remain your job.

Kotelys open on the typical floor plan of a sample residential building, drylining package: partitions, linings and ceilings drawn, totals per type in the Objects panel and the properties of a selected partition.

Further reading: Kotelys features, and the other guides.

Sources

Thresholds and values described as “taken for the example” are not rules: those of your contract (specification, bill of quantities) always prevail.

How to do a take-off: the method, from reading the specification to a checked total