Deciding how to procure your renovation is one of the most consequential choices you will make, and it is one that most homeowners arrive at without much information. Hiring a main contractor and managing trades directly both work, but they suit different project types, budgets, and circumstances. Getting this wrong costs money and, in some cases, months of delay.

The Core Trade-Off

A main contractor is a business (often a sole trader or small company) that takes overall responsibility for your project: they organise and manage the trades, take on the programme, and are your single point of contact. Their fee, the margin they add to sub-contractor costs, typically runs 15–25% on top of the labour and materials they procure. On a £60,000 kitchen and bathroom renovation, that is £9,000–£15,000 in management cost.

Managing trades yourself, engaging a plumber, electrician, tiler, plasterer, and joiner directly, saves that margin, but transfers all coordination risk to you. If the plumber runs two days late and the tiler cannot start, the cost of delay is yours to absorb.

When a Main Contractor Makes Sense

ScenarioContractorSelf-manage
Multiple trades working in sequence over 8+ weeksStrongly recommendedRisky
You work full-time and cannot be on site dailyRecommendedVery difficult
Project involves structural work, Building Regs sign-offRecommendedPossible but complex
Budget is £60,000+Contractor margin is proportionally sensibleSavings possible but effort high
You have renovation experienceEither worksViable
Single-trade job (e.g. bathroom only, loft conversion)Specialist firm or PMOften fine direct

A useful rule of thumb: if your project involves four or more separate trades working in sequence over more than six weeks, a main contractor will almost always save you money in delays and rework, even accounting for their margin.

What a Main Contractor Actually Does

Beyond booking the trades, a good main contractor:

  • Plans and maintains the programme (who is on site when, what must happen before the next trade arrives)
  • Takes responsibility for quality at each stage before the following trade covers up the work
  • Manages materials procurement and storage
  • Holds the contracts with sub-contractors and manages disputes
  • Takes on your client duties for site health and safety, which CDM 2015 passes to the contractor (or principal contractor) on domestic projects1
  • Notifies and liaises with Building Control where required

They are also the person you call when something goes wrong, and on any renovation of substance, something always goes wrong. Having a single accountable party is significantly less stressful than trying to arbitrate between four tradespeople who each blame the previous one.

The Case for Self-Managing

Managing your own project is not inherently reckless, many experienced homeowners do it successfully, particularly on mid-size projects where they have done it before. The saving is real: 15–25% of the trade costs can be £6,000–£20,000 on a substantial renovation.

To self-manage successfully, you generally need:

  1. Availability, You need to be reachable quickly and ideally able to visit site at least three times a week. Delays cascade fast when a decision cannot be made.
  2. Technical knowledge, You need to know what good work looks like and what questions to ask at each stage. Engaging an independent clerk of works or project manager for periodic inspection visits (typically £300–£600 per visit from a chartered surveyor) is a sensible middle ground.
  3. Cash flow management, You will be paying multiple invoices from multiple trades, often simultaneously. A clear schedule of values and retention plan matters.
  4. Contingency, Budget an additional 10–15% contingency over and above your trade quotes for the coordination costs, rework, and delays that come with self-management.

The Role of a Project Manager (PM)

A third option sits between the two: hire a professional project manager or clerk of works who does not themselves carry out the work but manages the programme and quality on your behalf, while you directly contract the trades.

A freelance construction PM or RICS-qualified project monitor typically charges £350–£650 per day or a fixed fee of 3–8% of project value. On a £100,000 project, a 5% PM fee (£5,000) may well cost less than a main contractor’s 20% margin (£20,000) while providing professional oversight.

This approach works especially well for larger self-build or extensive renovation projects where you want oversight without paying full contractor margin.

Vetting a Main Contractor

If you decide a main contractor is the right route:

  • Ask for a fixed-price tender (not a day-rate estimate) with a clear scope of works and programme
  • Check they carry public liability insurance (it is not a legal requirement, so ask to see the certificate; £5 million of cover is a sensible figure for a main contractor), and employer’s liability insurance if they have staff, which the law requires to cover at least £5 million2
  • Look for membership of a recognised trade body: FMB (Federation of Master Builders), NFRC (National Federation of Roofing Contractors for roofing-heavy projects), or registration with TrustMark, the government-endorsed quality scheme
  • Ask for references from the last two to three jobs of similar scale and actually call them
  • Ensure the contract specifies payment terms (avoid paying more than 25% upfront on any project over £5,000), a retention clause, and a defined variation process

Avoid verbal-only agreements on anything over £1,000. The Consumer Rights Act 2015 gives you some protection, but a written contract is far cleaner.3

Costs in 2026: Typical Day Rates

Understanding market rates helps you assess whether a contractor’s quote is reasonable:

TradeDay rate (2026, London)Day rate (2026, regional)
General builder / groundworker£280–£3804£220–£300
Plumber (domestic)£300–£4505£250–£3806
Electrician£280–£4207£230–£350
Plasterer£260–£380£200–£300
Tiler£250–£380£200–£300
Carpenter / joiner£260–£380£200–£300
Main contractor margin on above15–25%15–25%

A main contractor working in London on a medium renovation is effectively billing £350–£480 per day for each trade they supply once margin is factored in, but they are also accountable for the result.

The Bottom Line

Use a main contractor when: the project is large or complex, you do not have time to manage it yourself, or there are significant sequencing dependencies between trades.

Self-manage when: the project is smaller or single-trade, you have renovation experience, and you can genuinely commit the time to be an effective client.

A project manager or independent inspector is worth considering on projects over £80,000 where you want professional oversight but are willing to run the contracts yourself.

References (7)

Figures in this note were checked against the sources below on 30 September 2026. Superscript numbers in the text point to them. Every source the site cites, by topic.

  1. 1technicalvery strongHealth and Safety Executive, guidance.RN-D7GLU7HSE page (updated 7 October 2025) defining a domestic client under CDM 2015 as any individual having construction work done on their own home or a family member's home that is not part of a business. On a single-contractor project the contractor automatically takes on the client's legal duties; where there is more than one contractor the principal contractor takes them on, unless the client makes a written agreement for the designer to act as principal designer.
  2. 2technicalvery strongGOV.UK, guidance.RN-VR45QMGOV.UK guidance for employers. It says an employer must have employers' liability insurance from the moment they employ someone, with cover of at least £5 million.
  3. 3technicalvery strongThe National Archives (legislation.gov.uk), legislation.RN-F06Z1FSection 49(1), in Part 1 Chapter 4 of the Consumer Rights Act 2015, states that every contract to supply a service is to be treated as including a term that the trader must perform the service with reasonable care and skill. Section 49(2) directs the reader to section 54 for the consumer's rights when that implied term is breached. This is the single provision that makes poor workmanship by a builder a breach of contract without the homeowner having to prove anything was written down, and it cannot be excluded to the extent it would stop the section 54 to 56 remedies applying.
  4. 4costgoodCISRS.RN-RZNJD5A price, true at 2026-07. CISRS, the scaffolding industry's training scheme, reporting the CIJC pay settlement. Useful as a dated confirmation of when a rate took effect; the rates themselves come from the CIJC promulgation, which is the agreement rather than a report of it.
  5. 5costvery strongHomes and Communities Agency, a government page.RN-IJYN87A price, true at 2026-01. The GOV.UK publication page for the Homes and Communities Agency guidance on dereliction, demolition and remediation costs, prepared with Ove Arup and Partners. Held for its regional adjustment factors, which are what the register uses it for: the multipliers that take a national construction rate to a region. It is not a source of current prices, and the rates in the guidance itself are of its own date.
  6. 6costvery strongOffice for National Statistics.RN-MMT1DOA price, true at 2026-01. The ASHE Table 14 dataset gives annual estimates of paid hours worked and earnings for UK employees by sex and by full-time or part-time status, broken down to four-digit Standard Occupational Classification, which is the level that isolates individual construction trades such as bricklayers, carpenters, plasterers and electricians. Released 23 October 2025 as the 2025 provisional edition (zip, about 10.7 MB), with revised and provisional editions back to 2017. A correction dated 19 December 2025 suppressed annual pay estimates for SOC 3312 police officers in some areas; construction occupations are unaffected.
  7. 7costgoodJoint Industry Board for the Electrical Contracting Industry.RN-7N6Z4IA price, true at 2026-01. JIB Handbook 2026, Section 2: National Working Rules for the Electrical Contracting Industry, the negotiated national working rules and pay rates for electrical contracting, which is what a JIB-graded operative is paid rather than what a customer is charged

  1. Domestic clients: roles and responsibilities (CDM 2015), Health and Safety Executive, accessed 30 September 2026. hse.gov.uk

  2. Employers’ liability insurance, GOV.UK, accessed 30 September 2026. gov.uk

  3. Consumer Rights Act 2015, section 49: Service to be performed with reasonable care and skill, The National Archives, accessed 30 September 2026. legislation.gov.uk

  4. New CIJC pay rates confirmed for construction industry from 20 July 2026, CISRS / CIJC, accessed 15 September 2026. Priced at 2026-07, so no calibration is needed. cisrs.org.uk

  5. Guidance on dereliction, demolition and remediation costs, regional adjustment factors, Homes and Communities Agency with Ove Arup and Partners, accessed 21 September 2026. Priced at 2026-01, so no calibration is needed. gov.uk

  6. ASHE Table 14.6a, hourly pay excluding overtime by occupation, 2025 provisional, Office for National Statistics, accessed 21 September 2026. Priced at 2026-01, so no calibration is needed. ons.gov.uk

  7. JIB Handbook 2026, Section 2: National Working Rules for the Electrical Contracting Industry, Joint Industry Board for the Electrical Contracting Industry, accessed 17 September 2026. Priced at 2026-01, so no calibration is needed. jib.org.uk