My fee is 10–12% of the project cost, depending on how involved you want me to be. On a 20 m² single-storey rear extension with a £64,000–£84,000 build cost, that is about £7,000–£9,200 at the Standard level. Below: the worked example, what the fee covers, how it is typically recovered, and how it compares with other fee models.
There is no fee for the initial conversation, and if you already have builder quotations I will review them line by line at no charge. A kitchen and side extension I managed in Wimbledon was brought in under budget — read the case study.
That is the fee for a client-side residential project manager in London, paid by the homeowner. It is not a builder’s percentage and not an architect’s fee for drawings.
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Editor’s note, October 2026: this is the fee structure I use on South West London projects now. — Ben Murrell
10%
Tender, contract set-up and visits at the key stages of the build, so the builder is appointed on a proper basis and the stages that matter are checked.
11%
Regular site visits and cost control: quotes reviewed, contract in place, a live budget, variations tracked and payment requests checked against progress.
12%
Hands-on, start to finish: day-to-day management of the build right through to snagging.
| Build cost (20 m² × £3,200–£4,200/m², ex VAT) | £64,000 – £84,000 |
|---|---|
| HPM at 10% (Light) | £6,400 – £8,400 |
| HPM at 11% (Standard) | £7,040 – £9,240 |
| HPM at 12% (Full) | £7,680 – £10,080 |
So at the Standard level, HPM’s fee on this extension is about £7,000–£9,200. Build rate: Build Team’s published London mid-range of £3,200–£4,200 per m², build-only and ex VAT, the same figure the extension cost calculator uses. The example applies the percentage to that ex-VAT build cost for illustration; professional fees and statutory costs are separate (see below). How the fee is worked out for your project is agreed in writing before I start. I confirm where your project sits in the range once I know what you are building and how much you want handled.
Work out your own figure in the fees calculatorNo build cost yet? Extension cost calculator →
I will read them properly and come back to you on what is excluded, which “prices” are really provisional sums, and what I would want answered before anyone signs. If the quote is sound, I will tell you that too.
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What happens next: I aim to reply within one working day. If anything needs talking through, we arrange a short call. There is nothing to sign and no fee.
Project managers do not all sell the same thing, so the same project can be quoted in four quite different ways. The ranges below are from Checkatrade’s published cost guide, not HPM rates.
Checkatrade: 15–20% of total renovation spend (average 17.5%)
Suits: Projects where the manager is involved from tender through to completion.
Watch for: The fee moves with the build cost. Ask how it is worked out if the cost changes — this applies to HPM’s guide as much as anyone’s.
Checkatrade: £5,000–£7,000 per project (average £6,000)
Suits: A defined piece of work with a clear end point — reviewing quotes, setting up a budget and a variation process, getting you to a signed contract.
Watch for: Check exactly where the stage ends, and what happens on the day after it ends.
Checkatrade: £1,000–£3,500 a month (average £2,250)
Suits: Live projects where the value is regular site attendance and continuous coordination.
Watch for: Ask what a month buys — number of visits, response times, and what happens if the programme slips by three months.
Checkatrade: £100–£200 an hour (average £150)
Suits: Occasional, targeted input — a second opinion, a difficult meeting, a specific problem.
Watch for: Cheap to start, hard to forecast. Agree a cap or a review point so it cannot quietly become the most expensive option.
Source: Checkatrade, house renovation project manager cost(“Last updated: September 2026”), checked 28 September 2026. Treat market figures as a sense of scale, not a quotation. Applied to the same £64,000–£84,000 build cost, Checkatrade’s 15–20% range would be £9,600–£16,800 (Checkatrade quotes it on total renovation spend, so treat this as a rough comparison).
People search for a project manager’s hourly rate because it looks easy to compare. It is only easy to compare if you know how many hours the job will take, and on a build that runs for months, nobody does at the start.
An hourly or day rate is the right tool for occasional, targeted input: a second opinion on a quote, a difficult meeting with a builder, a specific problem. A percentage of the project cost suits a whole project, because you know the figure before you start and it covers the tender, the contract and the build. On the worked example above, HPM’s 11% fee of about £7,000–£9,200 is roughly what 35 to 92 hours would cost at Checkatrade’s published £100–£200 an hour.
Whichever model you are offered, ask the same question: what happens to the fee if the build cost or the programme changes?
HPM is a client-side project manager: appointed by you, paid by you, with no commercial relationship to the builder. Depending on the level you choose, the fee covers:
If a project manager charges a percentage of what you spend, their fee goes up when your project gets more expensive. You are hiring someone to challenge quotes, question allowances and stop costs drifting, and a percentage fee quietly rewards the opposite outcome.
HPM’s fee is a percentage of the project cost too, depending on the level of involvement, so ask me the same thing: how the fee is worked out, and agree it in writing up front. The same question applies to anyone in the chain: does the person advising me earn more if I spend more?An architect on a percentage fee, a builder pricing their own variations, a supplier paying referral commission. Independence is not a marketing word — it is a description of who pays whom.
This is what moves the figure between 10% and 12%. Some clients want everything handled; others want the tender and contract done properly and a visit at each key stage.
A £60,000 loft conversion and a £600,000 whole-house renovation are not the same job scaled up. More trades and more interfaces mean more to manage.
Most fee models are really a proxy for time on site. A project that takes nine months needs more management than the same project done in five.
Drawings approved, structural calculations done, planning granted, party wall notices served — a project arriving in that state needs less than one starting from a sketch.
A Victorian terrace already altered twice by previous owners carries far more unknowns than a straightforward extension on a sound house.
Before a builder is appointed is cheaper and considerably more useful than coming in to rescue a project that has already gone wrong.
Architect fees ≠ client-side PM fees. An architect appointment (design ± contract administration) is a different service and fee model. For how architect fees are typically structured, seearchitect fees UK & London.
A project manager coordinates the team; they are not a substitute for the people in it. These sit outside the fee and need their own line in your budget. Therenovation fees calculator shows sourced London ranges for each, ex VAT, alongside HPM’s 10–12%.
Not sure which of these your project needs?Architect, DIY or project manager: who should run your build?goes through it, anddo you need a structural engineer?covers the one people most often leave out. Planning first?Permitted development in four London boroughs.
Two fees are only comparable once you know what each one buys. These questions surface the difference:
There is a longer version in12 questions to ask before hiring a renovation project manager. The same discipline applies to builder quotes —how to compare builder quotes covers that side, and there is a printable comparison checklist.
Sometimes. Not always, and anyone who tells you otherwise is selling something.
On a small, straightforward job with a builder you already know and trust, the maths is thin, and I will say so rather than take the work. On a six-figure renovation with several trades, structural work and decisions landing every week, the recovery routes are real and they compound:
The mechanics are set out in trade prices vs retailand the most common renovation budget overruns. For build costs rather than fees, seeextension and loft conversion costs in London in 2026.
“Project management” covers a wide range of involvement. Two loft conversions of the same value can need very different amounts of management, depending on whether the drawings are resolved, how good the builder is and how many decisions are still open. That is why the guide is a range, 10–12%, tied to how much you want handled, rather than a single number.
So the conversation still comes first. Tell me what you are building, where you are in the process and what you would most like taken off your plate, and I will tell you which level fits and what that means in pounds. If the answer is that you do not need me, I will say that instead.
Not sure you need a project manager at all?Do I need a project manager for my extension?sets out when your builder or architect is enough and when independent help pays.
Weighing up whether to run it yourself? Seehow much time managing your own extension takes,what a builder's extra should cost,a payment schedule for a London extension andVAT on a house extension.
HPM’s fee guide is 10–12% of the project cost, depending on the level of involvement: 10% Light, 11% Standard and 12% Full. On the worked example on this page, a 20 m² standard single-storey rear extension at £64,000–£84,000 ex VAT comes to about £7,000–£9,200 at the standard 11%. There is no fee for the initial conversation.
HPM charges 10–12% of the project cost, depending on how involved you want me to be: 10% for tender, contract set-up and key-stage visits, 11% for regular site visits and cost control, and 12% for hands-on management from start to finish. On a 20 m² standard single-storey rear extension with a build cost of £64,000–£84,000 (ex VAT), 11% works out at about £7,000–£9,200. For comparison, Checkatrade’s cost guide (updated September 2026) puts project managers at 15–20% of total renovation spend (not just the build cost), or £100–£200 an hour for ad hoc work.
It depends on how much help you need. An hourly rate suits occasional, targeted input, such as a second opinion on a quote or a difficult meeting, but it is hard to forecast over a build that runs for months. A percentage of the project cost gives you a figure you can budget for at the start and covers the whole project. On the worked example, HPM’s 11% fee of about £7,000–£9,200 is roughly what 35 to 92 hours would cost at Checkatrade’s published £100–£200 an hour. Whichever model you choose, ask what happens to the fee if the build cost or the programme changes.
Checkatrade’s house renovation project manager cost guide (updated September 2026) quotes hourly rates of £100 to £200, averaging £150. HPM’s fee guide is a percentage of the project cost rather than an hourly rate, because most of the value on an extension or loft comes from being involved consistently across the whole build, not from occasional hours.
HPM’s guide is 10–12% of the project cost, depending on the level of involvement. Whoever you hire, HPM included, ask how the fee is worked out and agree it in writing up front. Checkatrade’s guide puts the market project rate at 15–20% of total renovation spend, averaging 17.5%, so it is not calculated on the same base as HPM’s project-cost percentage. Before comparing percentages, check what each one is calculated on (build cost only, or including fees and VAT) and what it includes.
Depending on the level you choose: reviewing quotes before anything is signed, running the tender and builder appointment, setting up the contract, payment schedule and variation process, site visits, a live budget with variations and payment requests checked, coordinating the architect, engineer, party wall surveyor and building control, sourcing materials at trade prices, and snagging through to completion. It does not include the architect, structural engineer, party wall surveyor, building control or planning fees, which need their own line in your budget. The renovation fees calculator shows typical London figures for each.
Structurally, it can. If a fee is a percentage of what you spend, it rises when the project costs more, which is the opposite of what you are hiring a manager to achieve. That applies to HPM’s percentage guide as much as anyone’s, so ask any project manager, HPM included, how the fee is worked out, and agree it in writing before you appoint them. Plenty of good people charge this way and manage the tension well, but you should know it is there.
It depends on the size of the project and the state it is in. On a small, simple job with a builder you already trust, the honest answer is often no. On a six-figure renovation with several trades, structural work and decisions being made weekly, the fee has a realistic chance of paying for itself through quote omissions caught before they become variations, materials bought at trade rather than retail prices, and delays avoided.
HPM works with homeowners across South West, West and Central London, including Wandsworth, Battersea, Clapham, Balham, Fulham, Putney, Earlsfield, Hammersmith, Chelsea, Kensington, Earl’s Court, Notting Hill, Belgravia, St John’s Wood, Richmond, Wimbledon and East Sheen. The first conversation is free.
Groundworks — the stage where budgets are most often lost, and the reason the cheapest time to involve someone is before a builder is appointed.
Related: when a client-side PM makes sensefor Wandsworth & Fulham extensions ·PM vs architect contract administration ·extension / loft budget planner ·renovation fees calculator.
Where your project sits in the 10–12% range, no obligation — and a straight answer about whether you need a client-side manager at all.
Get a project-specific feeOr speak to Ben directly: 07525 474 849 · benmurrell83@gmail.com