Quantity surveyor for contractors: bids, packages and changes
A quantity surveyor for contractors checks the quantity basis you use to prepare a bid, divide work into subcontract packages and explain changes during construction. Start with the decision you need to make: check a tender section, prepare a work package or compare design revisions. That purpose defines the documents, measurement scope and output, so the result distinguishes checked quantities from recorded assumptions and questions awaiting clarification.
What a quantity surveyor for contractors checks before a bid
First, establish the document set: drawings, specifications, the client's bill of quantities and a model where available. Record the revision and date of each document. Include amendments and clarification responses, identifying which items they may affect. Without a common revision baseline, two calculations can appear contradictory even though they were prepared from different information.
Next, agree the sections and items to be reviewed. You can commission measurement of a defined scope or a focused check of selected items. A sample check does not cover the whole tender. The output should state what was measured and what remains outside the review. Priorities can reflect the extent of the work, construction complexity and unclear information.
For each item, compare the description, unit and quantity with the relevant source. Look for work shown in the design but not identifiable in the bill, quantities that do not match the supplied revision, and descriptions that leave the work boundaries unclear. Record findings with document and location references for use in clarification questions. A lump-sum tender also needs a clear account of what was measured and what information is missing. The calculation itself does not allocate contractual responsibility.
Work packages that subcontractors can review
When work is divided among subcontractors, the original bill's section order may not be sufficient. Each package needs a description of its work, locations and interfaces with adjoining packages. Distinguish supply from installation, for example, and identify who prepares the background and completes the surrounding work. State exclusions so the reader does not have to infer them.
Shared site items, such as scaffolding, lifting and waste removal, belong in an agreed place in the bill with a clear allocation. Check for duplicate entries and items with no assigned responsibility. This structure helps you assess whether returned quotations cover the same scope, while the qualifications in each quotation still need review. The construction BOQ guide explains the section structure.
Updating quantities when the design changes
Select a baseline and a new revision, then define the areas and sections to compare. Keep the previous quantity alongside the new quantity and explain the change: added work, an omission, altered dimensions or a revised assumption. A changed description or unit needs attention even if the number stays the same. Do not combine unlike units simply to produce one difference.
| Field | Record | Purpose |
|---|---|---|
| Item and location | Item number, building, floor or area | Identify the affected work |
| Before and after | Quantities in the same unit and scope | Compare equivalent bases |
| Change source | Document, revision and detail reference | Allow the calculation to be checked |
| Open question | Missing information and the required clarification | Separate facts from assumptions |
The schedule can support preparation of a payment application or presentation of a change. It records the quantity calculation. Approval of payment or a variation is a separate step, subject to the project's review and engagement documents. If the scope is disputed, retain both interpretations and refer the question to the appropriate party. An assumption should not be presented as an accepted decision.
Before passing a quantity to procurement, establish whether it represents physical work, the bill's agreed measurement basis or an order requirement. Waste, packaging and construction stages may affect procurement quantities. Read the guide to different quantity types in a project.
What to send and what you receive
Send the available documents with a task description and target date: drawings, specifications, the bill, clarifications and a Revit model if available. Identify the current revision and the person coordinating answers. There is no need to produce new documents solely for the initial enquiry; state which inputs are not yet available.
In my work, I review the scope and collect questions before preparing a proposal. The written proposal defines the sections, stages and deliverables. Measurement can use a model or DWG and PDF drawings, depending on the supplied information. The measurement sources and assumptions are recorded so that you can return to them.
The output is an Excel file in the agreed structure, with items, units, quantities, missing inputs and clarifications. Any breakdown by floor, building or area is agreed in advance according to your needs and the available information. The quantity calculation file guide explains this documentation. Outputs are submitted for review at the agreed stages. Design changes or materially new information require a further scope assessment.
Construction experience and service boundaries
A quantity surveyor may have an engineering or registered building technician background. Yaakov Avital is a quantity surveyor and registered building technician with experience in quantity surveying and work for contractors since 2012. I measure every detail like a contractor: considering the work the quantity describes and how it connects to the documents, as well as the number itself.
My work as a quantity surveyor for contractors focuses on the measurement and records defined in the proposal. Pricing is an extra service: verbal feedback on prices together with the client, with no commitment. The submitted bid price remains the contractor's decision. Subcontractor outreach and collection of quotations are defined separately. See the quantity surveying fee guide; the task price and scope are set out in a written proposal. To contact a quantity surveyor, describe the check you need and the information already available.
Frequently asked questions
Can you check only one tender section?
Yes. Agree the section, areas and documents to be used. The result covers that defined scope and does not indicate that the rest of the tender has been checked.
What happens when the bill and drawings disagree?
Record the discrepancy with references to both sources and their revisions. Where information is insufficient to resolve it, present an open question rather than changing the quantity on a guess.
Is a change schedule enough to approve a variation?
The schedule documents quantities and the source of the change. It is not approval from the client or supervisor. Establish the project's review and submission requirements separately.
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.