Your team and the process
Do you need a quantity surveyor for a home project?
Short answer
Not on every project. A quantity surveyor, or QS, manages cost: early estimates and cost plans, the tender documents and tender report, valuations of work done for each payment, the cost of changes, and the final account. On a straightforward extension priced by builders against clear drawings, a specification and a schedule of works, the designer and the contract administrator often cover that ground between them.
A QS is most useful where the money is large or uncertain: a basement, extensive work to an older building, a project tendered on a bill of quantities, or a long build where changes and interim payments need checking line by line. The professional body for quantity surveyors is the Royal Institution of Chartered Surveyors (RICS), which publishes the measurement standards they work to.
What a quantity surveyor does, stage by stage
RICS publishes a standard scope of services for quantity surveyors in England and Wales (May 2022). A client ticks the services wanted. The ones that matter on a home project are these.
| Stage | Service in the RICS scope |
|---|---|
| Early design | Prepare an initial budget estimate to test feasibility (1.4.4); advise on the cost of alternative design and construction options (1.4.1); prepare and develop a cost plan and cash flow forecast (1.4.6) |
| Procurement | Advise on tendering and procurement options (1.6.1); prepare tender documentation (1.6.3), including bills of quantities to NRM 2 (1.6.4) or schedules of rates or activity schedules (1.6.5) |
| Tender | Check tenders for errors, omissions, exclusions, qualifications and inconsistencies (1.6.10); prepare a tender report (1.6.13); negotiate with tenderers (1.6.14) |
| Construction | Visit the site to assess progress for interim payments (1.7.2); advise on the cost of variations before instructions are issued (1.7.3); recommend interim payments and the release of retention (1.7.6) |
| Completion | Prepare and agree the final account (1.7.9) |
The early cost work follows RICS's NRM 1, described in what a cost plan contains.
How the QS relates to the contract administrator
The contract administrator runs the building contract for you: issuing instructions, certifying payments and certifying completion. The QS does the arithmetic behind the money. The RICS scope is worded accordingly: the QS prepares recommendations for interim payments and the release of retention. Under the JCT forms, the certificates themselves are issued by the contract administrator.
On a small home project the contract administrator often values the work as well, and no separate QS is appointed. On a larger one, splitting the roles means the payment figures are checked by someone whose whole job is cost. Either way, you should know before the contract is signed who values the work, who certifies it and how often. The role is set out in what a contract administrator does, and the payment rules that apply to homeowners in payment and retention for homeowners.
Where a QS earns the fee
There is no threshold in law or in the RICS scope. These are the conditions under which the cost work outgrows what a designer normally provides:
- The cost is uncertain. Basements, underpinning, and extensive work to older or listed buildings carry the most risk; see contingency.
- The project is tendered on quantities. A bill of quantities gives every tenderer the same measured quantities to price, which makes tenders directly comparable and variations easier to value. Someone has to measure it.
- The build is long, with monthly valuations. Each valuation needs checking against work actually done.
- Changes are likely. If the scope may move during the build, a QS pricing variations before they are instructed keeps the final account from surprising you.
A single-storey extension with a fixed scope, tendered to a few builders on the same drawings, specification and schedule of works, is usually simple enough for the designer to compare the tenders and for the contract administrator to value the work.
How to appoint one
Ask for a written scope that uses the RICS service numbers, so both sides know which services are included. Agree the fee per stage, and whether site visits for valuations are included or charged per visit. A QS can be appointed for part of the job only, for example an early cost plan and the tender report, with the contract administrator taking the valuations.