The anatomy of an item
In Belgian frameworks an element consists of three distinct components. Index, title and description are cited together.
| Component | Role |
|---|---|
| The index | numbering of the element within the classification |
| The title | short designation, the one appearing in the bill |
| The description | detailed content, divided into headings |
The title does not make the content. It is the description that states what the work comprises, which materials, which tolerances, which incidentals. A bill read without its descriptions is a list of headings, not a scope.
That is the first cause of misjudgment, and it is all the more frequent because bills often circulate alone, in a spreadsheet, detached from the specification. A bill separated from its description loses half its meaning.
The four ways of determining price
Belgian rules and the frameworks distinguish several ways of fixing the price of an item. The principal ones are recognised by customary abbreviations.
Provisional quantity. The rate is unitary, the quantity shown is an estimate, and payment follows quantities actually executed.
Lump-sum quantity. The quantity is fixed contractually. Any difference between stated and actual quantity gives rise to no adjustment.
Global price. The item is priced as a whole, without quantity or rate. It covers a scope defined by the description.
Provisional item. It appears in the bill without an amount, to flag work whose cost is dealt with elsewhere or remains to be defined.
The distinction between provisional and lump-sum carries the heaviest consequences, because it determines who bears the quantity difference. It is covered in the article on provisional and lump-sum quantities.
A provisional item deserves particular vigilance: it does not mean the work is free, nor that it is excluded. It means its cost does not appear on that line.
The unit carries a measurement rule
This is the most understated point of the subject. It concerns the unit of measure and its convention.
A unit is not a label: it is attached to a measurement convention stating how the quantity is calculated. Two different conventions produce two legitimate and distinct quantities.
| Unit | Question the measurement rule poses |
|---|---|
| Square metre | are openings deducted, and above what area |
| Linear metre | does measurement follow the centreline, inner or outer face |
| Cubic metre | is the volume net or gross, with what deductions |
| Kilogram | is weight theoretical or actual, waste included or not |
| Number | does the unit include accessories and installation |
Two bills using the same unit can therefore give different quantities for the same work, if deduction rules differ. This is frequent between frameworks and is a mandatory check when comparing, covered in the article on comparing a Walloon and a Flemish bill.
The costliest unit errors
Four configurations recur regularly.
Confusing developed and projected area, particularly on roofs. The gap is proportional to pitch and can be considerable.
Linear metres applied to work of varying section. Length says nothing about quantity of material, and a rate calibrated on an average section becomes wrong as soon as the section varies.
Number where an assembly is expected. An item counted by number that omits installation, fixings or connections transfers those works elsewhere, or nowhere.
The lump sum that absorbs imprecision. Making an item lump-sum because the quantity is poorly known does not remove the uncertainty; it shifts it to the contractor, who prices it accordingly.
What this means for a professional
Four rules.
Never price a bill without its descriptions. The heading does not define the scope.
Check the unit and the associated measurement rule, particularly on high-quantity items where an error of convention multiplies.
Identify provisional items and global prices before calculating a total, or the total means nothing.
Check consistency between unit and description. A description covering a complete assembly and a unit counting isolated pieces contradict one another.
This article reflects rules and professional practice at the date of checking and serves as orientation. It does not constitute legal advice and does not replace consulting the applicable framework.