Assessing a subcontractor's payment application: cuts, reasons and contras

Why the assessment matters

Your assessment becomes the basis of your payment notice. Under the Construction Act, that notice must state the sum you consider due and the basis on which it is calculated, and it must be given within the time the subcontract allows (no later than 5 days after the due date). Miss it, and the subcontractor's application can stand as the sum due unless you issue a valid pay less notice in time. Our guide to the Construction Act payment process sets out the timeline.

A good assessment is also your best protection in a dispute: a clear record of what was valued, what was cut and why.

Before you start

• Check the dates. Work out the due date, payment notice deadline, pay less deadline and final date for this application as soon as it arrives. Our free payment date calculator works them out.
• Check it was made properly: on time, to the right person, against the agreed contract sum analysis.
• Check compliance: is the subcontract signed, and are insurances in date? Many main contractors hold payment until documents are in place, but check what your subcontract actually allows before relying on it.

Value line by line

Assess each line of the contract sum analysis against what is on site: your QS's measure, the programme, the site manager's view and any photos. For each line record:

• the percentage or value the subcontractor applied for;
• the percentage or value you assess;
• a reason for every reduction, specific enough that the subcontractor knows what to fix. "Level 3 first fix not started at the valuation date" is useful; "overvalued" is not.

Specific reasons cut the arguments next month. Vague ones invite a dispute and weaken your notice.

Variations, materials and dayworks

• Variations: value instructed and agreed variations; record your valuation and reference beside theirs for anything disputed, so the gap is clear for the final account.
• Materials off site: only include them where the subcontract allows and its conditions are met, such as vesting, insurance and clear marking. Our guide to materials on site and off site covers the usual conditions.
• Dayworks: check them against signed daywork sheets and the agreed rates.

Contra charges

A contra charge deducts a cost you have incurred because of the subcontractor, such as cleaning, skip hire, damage or attendance you had to provide. To stand up, a contra should:

1. be allowed for by the subcontract;
2. be notified when it happens, not saved up;
3. come with evidence: dates, photos, invoices;
4. be shown separately in your assessment with its reason.

Contras that appear without warning at the end of a job are the ones that end in adjudication.

Retention and discount

Apply the retention rate, any cap and any main contractor's discount exactly as the subcontract states. Track what you hold for each package, so releases happen on time. Our guide to how retention works covers caps and release.

Issue the notice on time

• Payment notice: by the deadline, stating the sum due and how it is calculated, which your line-by-line assessment provides.
• Pay less notice: if you intend to pay less than the notified sum, by the deadline before the final date, again with the basis. See payment notices and pay less notices.
• Send it to the address the subcontract specifies and keep proof of when it went.

Common mistakes

• Issuing the notice late because the assessment was not started until the deadline.
• Cutting lines without reasons.
• Deducting contras that were never notified.
• Withholding payment for something the subcontract does not allow.
• Losing track of the gap on disputed variations until the final account.

Constructicore for main contractors receives every application in one format against the agreed breakdown, lets your QS assess line by line with a reason for every cut, records contras with their evidence, and reminds you before each notice deadline.

Published 29 October 2026.