The client says he is paying less. What now?

You applied for £18,000. He says he is paying £11,000, because of the kitchen, and the delay, and something the architect said. No paperwork, just a text on Friday afternoon.

There is a rule for exactly this, and it is short. Once a sum has been notified, it is payable in full unless a pay less notice arrives in time. That is section 111 of the Housing Grants, Construction and Regeneration Act 1996. Whether the work was really worth £18,000 is a separate argument for a later day.

First: does the Act cover your job?

It does not apply to a contract with a residential occupier, meaning someone who occupies, or intends to occupy, the dwelling as their home (section 106).

So on a rear extension for the family who live in the house, there is no notified sum and no pay less notice. What you can hold him to is your own contract, and if the contract is a two-page quote, that is what you have. Everything below is for jobs where the Act applies: a developer, a landlord, a company, or a subcontract.

What the notice has to be

A valid pay less notice does three things, and missing any of them is the usual reason one fails.

• It says the sum the payer considers due on the date of the notice.
• It says the basis on which that sum is calculated. Not just the deduction, the workings.
• It arrives before the deadline set by your contract, counted back from the final date for payment.

A text saying “I am paying eleven” fails the second test and probably the third. An email that sets out the sum and shows how it was arrived at can be a valid notice even if it is not labelled as one, so do not dismiss something just because it lacks a heading. Read what it says.

If no notice arrived

Then the notified sum is due in full on the final date for payment. That is the whole point of the section: it converts an argument about value into a deadline that either was met or was not.

What the notified sum is depends on what was served:

• The payer issued a payment notice under section 110A, and nobody served a pay less notice: their figure is the notified sum.
• The payer issued nothing at all, and your application complied with the contract: your figure is very likely the notified sum, which is why applications are worth getting right.

What to do this week

1. Look for a notice, properly. Go through emails from the relevant window, not just the last few days. You are looking for a sum and a basis, whatever it is called.

2. Work out the deadline. Take the due date, take the final date for payment from your contract, and count the pay less period back from it. If the notice is outside that window it is late, and late is the same as absent.

3. Write once, in writing, and keep it short. The sum notified, the date it fell due, that no valid pay less notice was served within the period, and that the full sum remains payable. No adjectives.

4. Decide what you want. Payment of the notified sum is one thing. Being right about the value of the work is another, and it is the one that gets settled in the next valuation, because interim payments are cumulative and this month’s under-valuation corrects itself next month.

5. Do not stop work on the strength of the argument alone. There is a right to suspend, it needs seven days notice in writing, and it does not exist on a residential occupier job.

Where the information stops

Whether a particular email is a valid pay less notice is a question people take to adjudication and sometimes lose. This page tells you what the notice has to contain and when it has to arrive. It does not tell you whether the one sitting in your inbox counts. If the sum matters, that judgement is worth an hour of a construction solicitor’s time, and it is cheaper before you write back than after.