What a contra charge is
A contra charge is a cost the employer incurs because of something the contractor did or failed to do, deducted from what would otherwise be paid. Common examples are cleaning, making good damage caused by another trade, attendance the contractor was obliged to provide, and work completed by others after a failure to perform.
It is different from a valuation reduction. Valuing work at less than was applied for is an assessment of what has been built. A contra charge is a claim by the employer against the contractor, run in the opposite direction.
That difference matters because the two are administered differently and challenged differently.
The word itself causes confusion, because it is used loosely on site to mean any deduction at all. Keeping the distinction clear internally is worth doing, since the two things have different evidential requirements and different notice consequences, and conflating them is how a valid deduction becomes an invalid one.
The conditions that make it stick
Three things generally have to be true. The contract has to permit the deduction, the cost has to be real and evidenced, and the deduction has to be notified in the manner and within the period the contract and the legislation require. [VERIFY: the notice requirements and periods for withholding payment under the contract in use and under the Housing Grants, Construction and Regeneration Act as amended.]
The third is where most contra charges fail. A perfectly legitimate cost, properly incurred and properly evidenced, becomes irrecoverable because the notice was late or was never issued in the form required.
That outcome is frustrating and it is not unfair. The notice regime exists so that a contractor knows what is being withheld and why, in time to respond.
Scale is worth thinking about before raising anything. A small charge that costs more in administration and relationship than it recovers is not a commercial win, and a pattern of trivial deductions damages credibility for the substantial ones. Pick the items that matter and evidence them properly.
Evidence, not estimate
A contra charge supported by an invoice, a dated instruction to the party who did the work, and a record of the original failure is difficult to argue with. One supported by an internal estimate of what something probably cost is not a charge, it is an opinion.
The most common weakness is the absence of a record of the original failure. The cost is evidenced and the reason for it is asserted, which puts the employer in the position of proving a negative.
A short dated note at the time the failure occurs, naming the location and the obligation not met, is what converts the later invoice into a recoverable cost.
Where it goes wrong commercially
Contra charges accumulate quietly and then arrive at the final account as a block, at which point they read as a negotiating position rather than as a set of individual costs. The contractor disputes them collectively, and the employer ends up conceding a proportion for reasons that have nothing to do with the merits.
Raised individually and contemporaneously, the same charges are far harder to resist, because each has its own record and each was known about at the time.
The difference in outcome between those two approaches is usually larger than the value of any single item.
Set off works both ways
Contractors also set off, most often against subcontractors, and the same principles apply down the chain. A developer whose contractor is deducting heavily from specialists has an interest in knowing, because a subcontractor who stops work over a disputed deduction affects the programme regardless of who was right.
It is also worth remembering that a right to set off can be limited or excluded by the contract, and bespoke amendments frequently touch it. [VERIFY: whether the contract in use restricts or modifies the general right of set off.]
Where the position is unclear, the safer route is a properly notified deduction with the reasoning stated, rather than a silent adjustment to a payment.
What this means for you
Raise contra charges when they happen, in writing, with the failure recorded and the cost evidenced, and follow the notice route the contract sets out.
Do not save them for the final account. A charge that was worth raising in month four and was not raised until month twenty two has lost most of its force, and the delay itself becomes the contractor’s answer.
Administering that properly through the job sits inside cost control and variations, and where the position ends up contested it moves into final accounts and disputes with the record already made.
One structural point worth checking early. Where the works are being funded, a deduction reduces the certified sum and therefore the drawdown, so a contra charge raised late in the job can create a cash timing issue of its own. Raising them as they arise avoids that as well as preserving their validity. Where we hold the employer’s agent appointment, the notice route is administered as part of the monthly cycle rather than assembled afterwards.