MeryttThe client changed the brief. Did the fee change too?
Extra work from client changes often goes unbilled. Not because the contract forbids the fee, but because nobody raises it while the job is running.
Why does extra work go unbilled in engineering consultancies?
Mostly because the change is not flagged when it happens. The work gets done in good faith, and the fee conversation waits until later. By then it is harder to have.
Engineers have been saying this for years. Writing in STRUCTURE magazine, a practising structural engineer put it plainly:
“Structural engineers frequently provide special or extra services without receiving appropriate additional compensation.”
He gave two reasons. The first is that scopes are not always clearly written down before work starts. The second is about people:
“many structural engineers are reluctant to request additional compensation when they are asked to provide special or extra services. They fear that such requests might adversely affect their relationships with their clients”
That column is American. The pattern is not. In the UK, a construction lawyer writing for the Association for Consultancy and Engineering said:
“It is all too common that the consultant leaves its claim for additional fees to the end of the project when the services are complete and they no longer have any leverage against their client.”
His article is mainly about prolongation and delay. But it also covers what appointments say about additional services, which is what this piece is about.
What do the standard appointments say about additional fees?
Most of the standard forms do give consultants a route to extra fees. The catch is usually timing and paperwork. This is how Beale & Co summarised them on the ACE site. It is a summary, not legal advice, so check your own appointment.
- ACE Professional Services Agreement 2017: additional fees if you have to do extra work or are delayed by others, under clause 8.2.
- NEC4 Professional Service Contract: a compensation event, as long as you notify it within eight weeks of becoming aware of it and follow the early warning and programme rules.
- RIBA Standard Professional Services Contract 2018: extra work for reasons beyond your control is paid on a time basis, unless agreed otherwise.
- FIDIC White Book 2017: additional fees for delay caused by the client, its other consultants or contractors.
Bespoke appointments are where it gets harder. Some say extra fees must be agreed before the extra work starts. Many public sector appointments have no variation mechanism at all. In both cases, the article says, a consultant who just carries on may find the extra fee very hard to recover.
The contract often allows for the change. The habit of raising it is what goes missing.
Where does a change slip through inside a practice?
This part is our view, not a study. It comes from how work moves through small professional firms in general. We think a change usually slips at one of three points.
- Spotting it. A revised brief arrives by email or comes up on site. The engineer just does it. Nobody decides, out loud, whether it is in the fee.
- Recording it. The hours go against the stage, not against the change. So the timesheet shows a stage running over, but not why.
- Raising it. The fee conversation is left to a director, at the end of the stage or the job. By then, as Beale & Co warn, the work is done and the client has little reason to agree.
None of these is a software problem. Most practices already have a timesheet or a practice management tool. One UK small practice principal, listing his own mistakes of the year at an IStructE conference, named inadequate time and cost controls, and added:
“good systems but struggle to get people to use them well”
How can you check whether this is costing your practice?
Take three recent projects that ran over. For each one, put four things side by side.
- What was agreed: the scope and fee in the appointment or fee proposal.
- What was done: the hours, stage by stage, from your timesheets.
- What changed: the revised briefs, RFIs and client emails that asked for more.
- What was billed: the invoices, and any variation that was raised.
Then ask one question of each change. Was it raised while the job was running, at the end, or never?
If most changes were raised while the job was running, you are in good shape. If most were raised at the end, or not at all, the fix is usually a small habit, not a new system. Someone needs to own the moment a change arrives.
Why does this matter more when hiring is hard?
Because hours are the thing you cannot easily buy more of. The IET found that 76% of UK engineering employers struggle to recruit for key roles. When every engineer is already busy, unpaid change work is not a rounding error. It is capacity you have already paid for and given away.
Change is also normal. One study of 177 projects, cited by the Get It Right Initiative, found client changes were a primary source of rework, behind designer error. That study covered construction projects as a whole, not consultancies alone. But it shows that changes will keep coming. The question is whether the fee keeps up with them.
This is the work we do at Merytt. We look at how changes flow through a practice’s projects and billing, and help put a simple process in place using the tools you already have. See how we work with engineering consultancies.
Where this comes from.
Every figure and quote is somebody else’s: published, dated and linked. We do not write numbers we cannot point at.
- Prolongation and fair recourse for consultantsWill Buckby, Beale & Co, published by the Association for Consultancy and Engineering, 31 March 2021. The quote on late claims, and the summary of the ACE, NEC4, RIBA and FIDIC forms. Mainly about prolongation and delay.
- Scope creepSTRUCTURE magazine, January 2019. A US practising structural engineer on extra services and why engineers do not charge for them.
- A look inside the IStructE Small Practitioners ConferenceTotal Synergy, September 2019. A UK small practice principal’s list of his own mistakes, including time and cost controls.
- Literature review, revision 3Get It Right Initiative, April 2016. Cites Hwang et al. (2009): of 177 projects, client changes caused 26% of rework. Construction projects as a whole.
- Latest UK engineering and technology skills stats 2025The IET with YouGov, 6 October 2025. The 76% recruitment figure.
Last checked 18 October 2026. Nothing here is legal advice. If you are deciding whether you can claim a fee, read your appointment and take advice from a construction lawyer.
Questions
Why do engineering consultancies lose fees on client changes?
Usually because the change is not flagged when it happens. The work gets done in good faith, the hours go against the stage, and the fee conversation is left to the end of the job, when it is hardest to agree.
When should a consultant raise additional fees for a change?
As early as the appointment allows, and within any notice period it sets. Under the NEC4 Professional Service Contract, for example, a compensation event has to be notified within eight weeks of becoming aware of it. Some bespoke appointments require extra fees to be agreed before the extra work starts.
What do the standard engineering appointments say about extra work?
According to Beale & Co, the ACE Professional Services Agreement 2017, the NEC4 Professional Service Contract, the RIBA Standard Professional Services Contract 2018 and the FIDIC White Book 2017 all give consultants some route to additional fees. Bespoke and public sector appointments are often less generous. Check your own appointment and take legal advice.
How can a practice check whether it is losing fees on changes?
Take three recent projects that ran over. Compare what was agreed, the hours by stage, the changes the client asked for, and what was invoiced. For each change, note whether it was raised during the job, at the end, or never.