Professional bill of quantities: the flags to raise before pricing
A professional bill of quantities is more than a list of items, units and quantities. It is also the result of reading the drawings, the specifications and the soil report together, and of marking gaps and questions before the BOQ goes out to contractors.
Measuring what is marked, and a professional bill of quantities
Good measuring puts into the BOQ exactly what is marked on the drawings. But not everything that has to be built is marked in one place. Some of the work appears only in the specification, some only in a consultant's report, and some does not appear at all and remains a question. A professional bill of quantities cross-checks the sources, records every gap and passes it to whoever makes the decision.
The quantity surveyor does not settle a conflict between consultants, and does not correct the design either. The quantity surveyor's job is to see the conflict, phrase a clear question and record which assumption was taken until the answer arrives.
Why you need a quantity surveyor who comes from the field
A quantity surveyor who comes from the field, an engineer or a registered building technician who worked on site, like Yaakov Avital, reads the drawings as someone who will also have to build from them. He usually knows which works are not drawn but are still carried out: site set-up, temporary works, and dismantling what was put up only for the construction period. He also knows the places where the drawings of different trades tend not to fit together, such as protected rooms (mamad: the reinforced safe room in every Israeli flat), plant rooms and the junctions between the structural frame and the finishes.
A contractor's payment application, an addition discovered in the middle of construction, or a dispute over how an item should be read all teach what is worth asking before the tender. These questions are part of the deliverable, no less than the quantities.
An example: soil replacement by the report and by the marking
In the example, the soil report recommends replacing the clay soil under the whole footprint of the building, plus one metre on each side, to a depth of one metre. On the structural drawing, the replacement is marked under only half of that area. Measuring only what is marked would put 260 m³ into the BOQ. According to the report, the work is 520 m³. A professional bill of quantities does not choose on its own: it marks the gap as a question to the geotechnical consultant and the structural engineer, and they decide.
| Item | Description | Unit | Quantity | Source |
|---|---|---|---|---|
| 01.030 | Excavation and removal of clay soil under the building, according to the soil report: the building footprint plus one metre on each side, one metre deep | m³ | 520.00 | Soil report |
| 01.040 | Imported fill, compacted in layers, in place of the replaced soil, according to the soil report | m³ | 520.00 | Soil report |
| — | Check: the same work according to the marking on the structural drawing, over half of the area | m³ | 260.00 | Structural drawing |
| — | Gap between the soil report and the marking on the drawing | m³ | 260.00 | Flag: question |
| 01.090 | Compaction tests of the compacted fill by an accredited laboratory | each | Missing | Missing |
The compaction tests line stays "missing": the number of tests is set by the soil report and the specification, and until that information is received the line has no quantity. The example is entirely synthetic and not from a real project. On every project, check against the soil report and with the geotechnical consultant and the structural engineer.
The flags that recur in my calculation files
Next to each of my calculations I keep a "notes and questions" sheet. A review of calculation files from past projects found about 150 notes and questions recorded by hand: dozens on large projects, and one or two on small ones. These are the types that recur, in general terms and without identifying details:
- A missing document or detail. The concrete grade does not appear in the structural drawings, or the interior design drawings have not been received.
- A conflict between documents. A consultant's report specifies a lowered ceiling in all the rooms, while the architectural drawing marks it in only some of them.
- A schedule that does not match. The protected room windows are missing from the aluminium schedule, or the number of flats in the permit drawings differs from the number in the working drawings.
- Model against detail. The model defines one type of steel section, and the detail shows another.
- Scope and responsibility. It is not clear whether removing the temporary ground anchors is included, or whether trimming the pile heads is included in the item.
- A visible assumption. When data is missing, the assumption taken until the answer arrives is recorded, so that it can be corrected.
- A site check. In an existing building, what is to be demolished and which dimensions need to be verified on site.
Missing data is not zero. A line without a source is marked "missing", and it states what is missing. A zero looks like an answer, and it can enter the pricing as if there were no work there.
What goes into the notes and questions sheet
For each question: the item, the document it came from, who it is addressed to, the assumption taken in the meantime, and its status. When the sheet is organised like this, it can be passed on as it is, as clarification questions in the tender, and the BOQ can be updated when the answers arrive. There is a separate page on the stages of BOQ preparation, and another on the soil report and its effect on the quantities: soil report and BOQ.
The difference between a BOQ that looks professional and a BOQ that works on site is the quantity takeoff behind it. When the takeoff is documented, every line can be checked, not just trusted.
Frequently asked questions
Why do I need a quantity surveyor if there is a model?
The model returns what was modelled in it. A quantity surveyor also checks what is not in it: details, specifications, consultants' reports and works that are not drawn. More on the role on the page about the quantity surveyor's role.
What makes a professional bill of quantities?
Clear items, consistent units, quantities whose source can be traced, and a notes and questions sheet that explains what was assumed and what is still open.
Does the quantity surveyor decide conflicts between consultants?
No. The quantity surveyor marks the conflict and phrases a question. The project's designers and consultants decide, and the BOQ is updated according to the answer.
How many questions is a lot?
It depends on the project and the design stage. In a large project at tender stage, dozens of questions are normal. What matters is that each question is well phrased, addressed to the right person and closed. More on the page about a quantity surveyor for construction projects.
Have a project? Tell me briefly what the project is and what already exists. When the project is a good fit, I usually reply with focused questions and a written quote.
Contact me for a quote* Created with AI for marketing, for illustration only. Not reviewed by Yaakov Avital and not professional advice. Every project must be checked on its own by a professional quantity surveyor and an engineer.