Quantity Surveyor

A quantity surveyor, often called a QS, is a construction cost professional whose role can cover estimating, cost planning, procurement advice, valuing work, reviewing changes and preparing a final account. The exact duties depend on who hires the QS and the contract, so a QS working for a client may have a different remit from one employed by the contractor.

Owners should engage the right skill for the project, because a refurbishment, civil-engineering job and specialist plant installation may need different experience, and they should check qualifications, references, independence and the scope of appointment. Cost advice should begin while design choices are still flexible, since an early estimate can show whether a proposed building fits the available budget before drawings are final.

As detail improves, the QS updates quantities, rates and risk allowances, and early numbers should be presented as estimates with assumptions rather than promises of a final price. RICS describes quantity surveyors as professionals who manage construction costs and value through a project's life, and its guidance on final account procedures explains the importance of agreeing the final contract value and documenting adjustments; these sources describe professional practice, not a guarantee, because project outcomes also depend on design, market prices, management and contractual risk allocation.

A cost plan breaks the project into elements such as structure, services, finishes and external works, which helps an owner see which choices drive spending, whereas a headline total without detail is hard to test or update. Track both the approved budget and the current forecast so a risk can be raised before invoices arrive.

Tender work may include quantities, pricing schedules and comparisons of bids, and a QS can check whether bidders priced the same scope and whether exclusions or provisional sums differ, because the lowest headline tender is not necessarily the lowest comparable cost, so clarify qualifications before recommending an award and keep an audit trail of the evaluation. During construction, progress payments usually depend on work valued under the contract, and a QS may measure work done, check materials and assess the amount due for an interim certificate.

The certifier named in the contract may be a different person, so do not assume the QS alone has authority to approve payment or alter the agreement. Variations need timely cost analysis, because a design change can affect materials, labour, programme and related preliminaries, so price it before instruction where possible, then track the authorised amount and forecast effect.

If work must proceed urgently, record the instruction and valuation method, because unchecked changes can consume the contingency while the original budget still appears intact. A practical forecast compares approved budget, committed orders, paid amounts and forecast remaining cost; if the latest forecast is $10.6 million against an approved budget of $10 million, the forecast variance is $600,000 over budget, which is not necessarily the final overrun.

State which changes are approved and which are still estimates or claims. The final account reconciles the starting contract sum with agreed variations and other permitted adjustments, and some claims may remain disputed.

A QS can prepare or review the evidence and advise on the amount but cannot settle a legal dispute without authority, so keep correspondence, measurements and instructions traceable to each adjustment. A quantity surveyor gives a project a structured view of cost, commitments and payment, which is strongest when the scope is clear, records are current and warnings are acted on; no professional can promise a specific final variance or eliminate construction uncertainty, so define whether the QS is advising only or also administering part of the contract, and use the advice to make decisions before costs become irreversible.