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
| Scenario | Contractor | Self-manage |
|---|---|---|
| Multiple trades working in sequence over 8+ weeks | Strongly recommended | Risky |
| You work full-time and cannot be on site daily | Recommended | Very difficult |
| Project involves structural work, Building Regs sign-off | Recommended | Possible but complex |
| Budget is £60,000+ | Contractor margin is proportionally sensible | Savings possible but effort high |
| You have renovation experience | Either works | Viable |
| Single-trade job (e.g. bathroom only, loft conversion) | Specialist firm or PM | Often 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 site health and safety responsibility (legally required for most construction work under CDM 2015)
- 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% on labour-only costs can be £6,000–£20,000 on a substantial renovation.
To self-manage successfully, you generally need:
- 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.
- 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 (£300–£600 per visit from a chartered surveyor) is a sensible middle ground.
- Cash flow management — You will be paying multiple invoices from multiple trades, often simultaneously. A clear schedule of values and retention plan matters.
- 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 adequate public liability insurance (£5 million minimum) and employer’s liability if they have staff
- Look for membership of a recognised trade body: FMB (Federation of Master Builders), NFRC (National Federation of Roofing Contractors for roofing-heavy projects), or accreditation with Trustmark
- 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.
Costs in 2026: Typical Day Rates
Understanding market rates helps you assess whether a contractor’s quote is reasonable:
| Trade | Day rate (2026, London) | Day rate (2026, regional) |
|---|---|---|
| General builder / groundworker | £280–£380 | £220–£300 |
| Plumber (domestic) | £300–£450 | £250–£380 |
| Electrician | £280–£420 | £230–£350 |
| Plasterer | £260–£380 | £200–£300 |
| Tiler | £250–£380 | £200–£300 |
| Carpenter / joiner | £260–£380 | £200–£300 |
| Main contractor margin on above | 15–25% | 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.
