The Essentials
- A quantity surveyor handles the money on a project: what the work should cost, what the tender returns actually mean, and what is owed at each stage.
- The cost plan is drawn up before the design is finished, because that is the last point at which changing it is still cheap.
- Tender analysis normalises prices that are not comparable, and the useful finding is usually a gap in scope rather than the lowest number.
- Interim valuations pay for work that has actually been done, so the money does not run ahead of the progress on site.
- The final account settles variations and claims, and loosely recorded changes are what make it expensive.
Most building projects do not fail on site. They fail on paper, months earlier, when a budget is set against a drawing that is not finished, a price is accepted without anyone checking what it excludes, or a change is agreed on site and written down nowhere. Quantity surveying is the discipline that closes those gaps, and it is the one professional role on a project whose entire job is the money.
London makes the role more useful than it is elsewhere. More than a quarter of the capital’s homes were built before 1919 and another fifth between 1919 and 1944, so the work usually starts with older masonry, uneven floors and layouts that have already been altered more than once. Those are the conditions in which the quantity of work is genuinely uncertain until somebody measures it.
Cost Planning And Estimating
The first number on a project is produced when the least is known about it, and it tends to be the number everybody remembers. A cost plan exists to make that early figure honest and to keep it honest as the design moves.
An order-of-cost estimate sets the first budget against whatever exists, which may be no more than a sketch and a floor area. As the design firms up it becomes an elemental cost plan, which splits the total across substructure, frame, envelope, finishes, services and external works. The split is the useful part. A single total tells you the project is over budget; an elemental plan tells you which element moved and whether it moved because of the design or because of the ground.
Value engineering belongs at this stage too. It is at its most effective while specifications and build-ups can still change, and at its least effective once the drawings are approved and materials are on order.
Tender And Procurement Support
Three prices that look similar are rarely comparable. Each contractor has read the same drawings and made different assumptions about what is included, what is provisional and what somebody else is supplying.
Tender documents fix that before it happens. A bill of quantities, or at minimum a detailed schedule of works, gives every contractor the same measured list to price, so what comes back can be compared line by line. Where that is not practical, the analysis does the same job afterwards: normalising the returns onto a common basis, pulling out the exclusions and qualifications, and identifying which provisional sums are placeholders that will grow.
The outcome of a tender analysis is rarely “this one is cheapest”. It is more often that one return has priced work the others have left out, and the apparent saving disappears the moment that work has to be done anyway.
Contract Administration And Commercial Management
Once work starts, the contract is the only thing that decides who pays for what when something changes. Contract administration is the running of it: issuing instructions properly, recording variations as they are agreed rather than as they are remembered, tracking the programme against the dates the contract actually names, and dealing with extensions of time and loss and expense on the terms that were signed.
This is the least visible part of the role and the part that decides the final account. A variation agreed verbally on site in week three becomes an argument in month nine. A variation priced and instructed in writing in week three is a line in a schedule.
On projects that run several packages at once, which is normal where a house extension sits on top of fresh groundwork, the commercial management also means keeping the interfaces between packages from becoming nobody’s scope.
Valuations And Interim Payments
Payment on a building contract is not a deposit followed by a balance. It runs on interim valuations: at set intervals the work genuinely completed is measured, materials properly on site are counted, and a payment notice is issued for that amount.
The discipline matters in both directions. It stops a contractor funding your project out of their own cash flow, which is how a building contractor ends up off site chasing work that pays faster. It also stops payment running ahead of progress, which is the position nobody wants to be in if the job stalls, because the only leverage left on a contract is the money not yet paid.
Retention, defects and the release dates attached to them all hang off the same valuation process, which is why the records kept during the build decide how simple the end of it is.
Final Accounts And Where Disputes Start
The final account is the agreed total of what the works actually cost: the contract sum, plus every instructed variation, plus or minus the remeasurement of provisional and measured items, with any claims settled.
Where final accounts go wrong is almost always evidence rather than principle. Changes that were never instructed in writing, dayworks sheets nobody signed, provisional sums that were spent without a comparable price, delays with no contemporaneous record of what caused them. None of those are complicated arguments in themselves. They are simply unprovable a year later.
That is the whole case for the role. A quantity surveyor does not make a project cheaper by wanting it to be. The saving comes from the budget being tested before it is committed, the prices being comparable before one is accepted, and the changes being recorded on the day they happen.
Tell us the project, the stage it is at and roughly what size it is, and we put the detail in front of a cost consultant who works on that kind of job in your part of London.
Questions
What does a quantity surveyor do on a project?
They set and defend the budget. In practice that means the early estimate and cost plan, the tender documents and the analysis of what comes back, the valuation of work done each month, the pricing of variations as the job changes, and the settlement of the final account at the end.
When should I appoint a quantity surveyor?
As early as there is something to price, which is usually the first sketch scheme rather than the finished drawings. Appointing one after the tender has gone out means the budget was set by whoever priced it, and the scope is already fixed.
How is a quantity surveyor's fee usually structured?
Commonly either a percentage of the construction value or a fixed fee per stage, sometimes a time charge on smaller pieces of work. Which structure fits depends on the size of the project and how much of the job you want covered, so the figure comes from the scope rather than from a standard rate.
What is a bill of quantities?
A measured list of everything the works contain, item by item, with the quantity of each. Every contractor prices the same list, so the returns can be compared line by line instead of as three lump sums that each assume something different.
What is the difference between an estimate and a cost plan?
An estimate is a single figure for the whole job. A cost plan splits that figure across the elements of the building, so when the design moves you can see which element moved and by how much.
Do domestic projects need a quantity surveyor?
Not every one. Larger domestic work with structural alterations, a long programme or several trade packages benefits most, because that is where variations multiply and where the difference between tender prices is largest.
How can project costs come down without cutting quality?
Value engineering looks at what each element is costing against what it is contributing, and substitutes build-ups, specifications or sequencing rather than removing the work. It is effective while the design is still movable and much less so once materials are ordered.
