Which figure do they actually have to pay?

You applied for £24,000. The architect thinks £19,000. The client has paid £15,000 and gone quiet. Which number is actually owed?

The Housing Grants, Construction and Regeneration Act 1996 answers that with one idea: the notified sum. Under section 111, the payer must pay the notified sum on or before the final date for payment. Not the fair figure, not the figure they prefer. The notified one.

First: does the Act cover your job?

The Act does not apply to a contract with a residential occupier, someone who occupies or intends to occupy the dwelling as their home (section 106). On a rear extension for the family living in the house there is no notified sum at all, and what is owed is decided by your contract and, failing that, by an argument. Everything below is for jobs the Act covers: developers, landlords, companies, subcontracts.

Where the number comes from

In order:

• The payer served a payment notice within five days of the due date (section 110A): their figure is the notified sum, even if it is lower than yours.
• The payer served nothing, and your application was made under the contract: your application can stand as the notice, and your figure becomes the notified sum. This is why applications are worth doing properly, on the right day, with the sum and the basis stated. See is my invoice a payment application.
• A valid pay less notice arrived in time (section 111): the notified sum is reduced to the figure in it. Late or vague notices do not count. See the client says he is paying less.

Owed now is not the same as right forever

Being entitled to the notified sum this month does not settle what the work was worth. Interim payments are cumulative, so an over-payment or under-payment corrects itself in the next valuation. What the Act protects is cash flow between valuations: pay now, argue in the next cycle.

What to do this week

1. Establish the notified sum for the unpaid cycle. Find their payment notice, or the absence of one, and any pay less notice, and check its date against the contract deadline.

2. Write one short letter. The sum, how it became the notified sum, the final date for payment, and that it remains unpaid. No adjectives.

3. If it still does not arrive, the remedies start: interest, and on non-domestic jobs suspension with seven days notice.

Where the information stops

Whether a particular document was a valid notice, and whether an application was made under the contract, are exactly the questions adjudications turn on. If the gap between the figures is serious, that judgement is worth a construction solicitor before you write anything long.