Adjudication for subcontractors: the 28-day clock, what it costs and how the decision gets enforced

Published 7 September 2026 · VariationFlow

The construction adjudication process explained for UK subcontractors: the right to refer under section 108, the seven-day appointment and referral, the 28-day decision and who can extend it, what the adjudicator can decide, what it costs and who pays, how a decision is enforced in court, and when adjudication is the wrong tool.

A mechanical subcontractor’s final account has sat at £96,000 for four months. The main contractor has not so much disputed the figure as declined to engage with it: two meetings cancelled, one email promising a response “once the client has certified”, then nothing. On Monday 7 September the subcontractor serves a notice of adjudication. By Monday 14 September an adjudicator is appointed and the dispute is referred. The decision is due by Monday 12 October. If the main contractor does not pay what that decision says it owes, a court will order it to, in weeks rather than months. The silence ends because a clock has started, and the clock is the whole point of the procedure.

What is construction adjudication?

Construction adjudication is the statutory fast-track dispute procedure in section 108 of the Housing Grants, Construction and Regeneration Act 1996. Any party to a construction contract may refer a dispute (the Act says “dispute” includes any difference) to an independent adjudicator, at any time. The adjudicator must reach a decision within 28 days of the referral. The decision binds the parties as soon as it is delivered and stays binding until the dispute is finally determined by a court, by an arbitrator or by agreement. Where a contract’s own adjudication clause does not meet section 108, the adjudication provisions of the Scheme for Construction Contracts apply in its place. The design intent is that money keeps moving down the chain while the argument continues: pay now, argue later.

Can a subcontractor adjudicate, and when?

Yes, on any contract the Act covers (the Construction Act payment rules guide sets out the definition and the exclusions), and at any time. Section 108(2)(a) requires the contract to let a party give notice of its intention to refer whenever it chooses, so a clause that tries to hold adjudication back until practical completion, or to require mediation first, does not comply, and the Scheme takes over. Two limits matter in practice. There has to be a dispute to refer, which means a claim that has been put to the other side and rejected, or left unanswered for long enough that a refusal can be inferred; an adjudicator appointed on a claim nobody had yet seen has no jurisdiction. And one adjudication decides one dispute: bundle three unrelated arguments into a single notice and you invite a jurisdiction challenge that can sink all three. Frame the notice tightly, around one dispute and one figure.

What does the 28-day clock actually look like?

• Day 0: the notice of adjudication. Under paragraph 1 of the Scheme it sets out briefly the nature of the dispute, where and when it arose, the redress sought and the parties’ names and addresses, and it goes to every other party to the contract. Everything that follows counts from this date.
• Days 0 to 7: the appointment. You ask the adjudicator named in the contract, or the nominating body the contract names, or failing both any adjudicator nominating body. The body must communicate its selection within five days of the request (paragraph 5), and the person asked must say within two days whether they will act (paragraph 2). If the body misses its five days you may agree a person with the other side or go to another body.
• Day 7 at the latest: the referral notice. Paragraph 7 requires the dispute to be referred to the adjudicator in writing not later than seven days from the notice of adjudication, with the contract and every document you intend to rely on, and copies to the other party at the same time. This is your case in full. There is no second bite, so the referral is written before the notice goes out, not after.
• Days 7 to 35: the adjudication. The adjudicator sets the timetable (paragraph 13): typically a response from the other side within a week or two, sometimes a reply and a rejoinder, occasionally a meeting or a site visit. The decision is due 28 days after the referral was received (paragraph 19).
• Extensions. The adjudicator may take up to 14 more days with the consent of the referring party alone, so 42 days is your call and nobody else’s. Anything longer needs both parties to agree after the notice. If no decision arrives in time, either party may start again with a fresh notice.
• Delivery. The decision binds on delivery (paragraph 23), and unless the adjudicator directs otherwise it must be complied with immediately (paragraph 21). Ask for reasons in the referral: paragraph 22 obliges the adjudicator to give them if requested, and a reasoned decision is easier to enforce and harder to attack.

What does the adjudicator actually do?

More than a judge would. Section 108(2)(f) and paragraph 13 of the Scheme let the adjudicator take the initiative in ascertaining the facts and the law: request documents and written statements, meet and question the parties, visit the site, carry out tests, and appoint an expert or a legal adviser after telling the parties. The adjudicator must act impartially and avoid unnecessary expense (paragraph 12), must consider everything relevant that is submitted, and must make available to both sides any information relied on (paragraph 17). A party that ignores a direction does not stop the process. Under paragraph 15 the adjudicator may carry on without it and draw such inferences from the failure as the circumstances justify. That sentence is why a main contractor that “does not recognise” the adjudication and refuses to take part is making a mistake, and why you should never be the party doing it.

What does adjudication cost, and who pays?

• The adjudicator’s fees and expenses. Paragraph 25 entitles the adjudicator to a reasonable amount, which the adjudicator decides, and makes the parties jointly and severally liable for it. In practice the decision usually directs the losing party to pay them, but if it does not, the adjudicator can look to you for the whole fee and you recover it from the other side.
• The nominating body’s fee for making the appointment, where you use one.
• Your own costs: your time, and a claims consultant or solicitor if you instruct one. These are not recoverable from the other side. Section 108A makes any clause allocating adjudication costs ineffective unless it is in writing in the contract and confers power on the adjudicator to allocate the adjudicator’s own fees and expenses, or is agreed in writing after the notice of adjudication. So a subcontract clause that makes you pay the main contractor’s costs whatever the outcome is dead, and so is its mirror image.
• Proportionality. Several nominating bodies run capped-fee procedures for smaller disputes; ask before you nominate. On a five-figure sum a fully lawyered adjudication can cost more than it recovers, and the smash-and-grab guide sets out that calculus.

What can the adjudicator decide?

Paragraph 20 of the Scheme gives a wide remit inside the dispute referred. The adjudicator may open up, revise and review any certificate or decision given under the contract unless the contract makes it final and conclusive, may decide that a party is liable to make a payment and when it is due, and may decide what interest is payable, at what rate and for what period. So a payment certificate that undervalued your variations is not the end of the matter: an adjudicator can revalue it. A clerical slip in the decision can be corrected within five days of delivery (paragraph 22A). What the adjudicator cannot do is decide a dispute that has already been decided. Paragraph 9 obliges the adjudicator to resign where the same or substantially the same dispute has been adjudicated before, which is one more reason to get the first one right.

How is an adjudicator’s decision enforced?

The decision is binding, but it is not a court order, so a party that will not pay has to be taken to court. The route is an application to the Technology and Construction Court for summary judgment, and the courts have treated the enforcement of adjudicators’ decisions as a matter of policy since the Act came into force: the procedure is expedited and the grounds on which a losing party can resist are narrow. It may argue that the adjudicator had no jurisdiction (no construction contract, no crystallised dispute, more than one dispute, the wrong parties), or that the process was so unfair that it breached natural justice. It may not argue that the adjudicator got the facts or the law wrong. That is what the final determination is for, and the money is paid first. Most payers know this, which is why most decisions are paid without a hearing, and why a notice of adjudication so often produces the payment that six months of emails did not.

One situation changes the arithmetic. If the paying party is insolvent, a decision in your favour makes you an unsecured creditor holding a piece of paper; adjudicating against a company in administration or liquidation is rarely worth the fee, and suspending earlier, or taking security, is the better protection. If you are the one in a formal insolvency process, the Supreme Court held in Bresco v Lonsdale (2020) that you may still adjudicate, though enforcement of the decision may be stayed while the mutual account is worked out.

When is adjudication the wrong tool?

• The dispute has not crystallised. Send the claim, get the rejection or the silence, then refer. A notice served before the other side has had the chance to refuse is a jurisdiction argument handed to them for free.
• The sum is small against the cost of running it properly. A letter before action citing the statutory interest and the right to suspend is often the better first move.
• Your evidence is thin. The adjudicator decides on the documents in the referral, to a timetable that leaves no time to go and find the ones you should have kept.
• The relationship is worth more than the invoice. A notice of adjudication is a formal step and the other side will treat it as one. Sometimes the statement of account and the letter do the whole job.
• The payer is insolvent, for the reason above.

The records that decide it

• The instruction trail for every variation: who said what, when, in what form, with the photograph and the location.
• Every application and every payer notice, with the date it was served and how, because the adjudicator will count the days.
• A running account, gross, certified, paid and retained, cycle by cycle, so the figure in the notice of adjudication is a figure you can defend line by line.
• The correspondence that shows the claim was made and refused, which is what turns a difference into a dispute.
• All of it in one bundle, ready to go with the referral on day seven, not assembled during the seven days.

VariationFlow builds that bundle as the job runs: every variation is captured on site with a photograph, location and timestamp, linked to the instruction and to the application it was claimed in, the payment timeline records what was served and when, and the audit trail exports as a single dated record. This guide is general information, not legal advice. Where a contract’s adjudication clause complies with section 108 it governs the procedure, and where it does not the Scheme’s adjudication provisions apply in its place, so check your executed subcontract and take advice from a construction solicitor or claims consultant before serving a notice.