The certificate is an assessment, not a receipt
Each month the contractor submits an application for payment. The named certifier then values the works and issues a certificate. The purpose of interim valuation certification is to establish what has genuinely been built, not to process what has been claimed.
That distinction sounds obvious and it is routinely lost. Certifying close to the application every month is fast, keeps the relationship comfortable, and produces no visible problem until the point at which there is not enough work left to correct the position.
The mechanics differ between contracts and between procurement routes, but the principle does not. Somebody independent of the party being paid establishes the value, and the payment follows from that assessment rather than from the request. Where the same person prepares the application and approves it, there is no assessment happening at all.
Where the gap opens
Four things drift. Percentage completion on partly finished elements, which is a judgement and therefore optimistic when unchecked. Materials on site, which have rules attached to them about ownership and protection. Preliminaries, which are frequently claimed at a straight line rate regardless of actual resource. And variations, claimed at applied value before they have been assessed.
None of these are large in a single month. All of them compound, and they compound in one direction. A project paying two per cent ahead of value each month has advanced a meaningful sum by the time anybody measures properly.
Why it matters more than it looks
Overpayment is not simply a timing issue. Money paid early is money no longer available to hold, and retention plus the unpaid balance is the only practical means of ensuring the last five per cent of work gets finished.
It also affects the funding position. Where a facility is drawn against certified value, a certificate that overstates progress produces a drawdown that overstates it too, and the lender’s own surveyor will eventually say so. We covered that from the funding side in drawdown certification explained.
What a proper valuation involves
Attendance on site, measurement against the contract documents, and a written assessment that states what has been valued and what has been rejected and why. It takes longer than reviewing a spreadsheet, which is why fee levels quietly determine how thoroughly it is done.
The payment and notice regime then has to be administered to the timetable the contract and the legislation set, because the consequences of missing a notice are real. [VERIFY: the payment notice and pay less notice periods under the Housing Grants, Construction and Regeneration Act as amended and as modified by the contract in use.]
Retention, and why it is the last instrument you hold
Retention is a percentage withheld from each payment, released in stages, and it is the only practical mechanism for ensuring the final few per cent of work gets finished. It is the client’s money, held by the client, and available immediately.
That matters because everything else available to a developer at the end of a job is slow. Damages require establishing delay. A claim requires proceedings. Retention requires nothing except not paying it out, which is why the position built through twelve or twenty four monthly certificates decides how much of it is still there when it is needed.
A project that has certified generously each month arrives at practical completion with the retention already reduced in real terms, because the outstanding balance is smaller than the outstanding work. At that point the incentive structure has inverted and the contractor has more to gain from moving on than from finishing.
The proportions and release points are set by the contract. [VERIFY: retention percentage and release stages under the contract edition and amendments in use.] What is not set by the contract is whether the monthly assessment was done properly, and that is what determines whether the mechanism still works when you need it.
What this means for you
Ask to see the difference between application and certificate for the last three months. If it is zero every time, ask what was measured. A valuation that never disagrees with the application is not an assessment.
Where the certifying role and the commercial assessment sit with the same appointment, the two stay joined up. That is how we run it, as employer’s agent where we are named in the contract, and as client side quantity surveyor where we are not.
If you want a single number that tells you whether the process is working, take the certified value at the last valuation and compare it with the value of work you can see on site and in the records. Where those two are close, the assessment is real. Where the certified figure is comfortably ahead, the position has already started to drift and the remaining months are the only opportunity to correct it.