A general builder is the most common type of contractor for domestic residential projects in the UK. Unlike specialist subcontractors, a general builder can carry out a wide range of trades themselves - brickwork, carpentry, concrete, plastering coordination, drainage and groundworks - and will manage and supervise specialist subcontractors where needed. For projects such as extensions, loft conversions and whole-house refurbishments, a general builder typically acts as the main contractor, coordinating the programme and all trades on your behalf.
What they do
- Project management of small to medium builds and refurbishments
- Brickwork and blockwork - walls, foundations and piers
- Concrete and foundation works
- Carpentry and joinery - first and second fix
- Plastering coordination and making good
- Drainage and groundworks
- Supervision of specialist subcontractors (electricians, plumbers, roofers)
- Snagging and defect rectification at project completion
When you need one
A general builder is the right first call for most domestic building projects - they can assess scope, coordinate trades and take responsibility for the build from start to finish.
Typical costs (UK, 2025)
| Job type | Typical cost |
|---|---|
| Day rate | £180 - £320/day |
| Small extension (supply and fix) | £15,000 - £50,000+ |
| Garage conversion | £8,000 - £20,000 |
| Full house refurbishment | £20,000 - £80,000+ |
| Garden room or outbuilding | £8,000 - £30,000 |
| Hourly rate | £35 - £65/hr |
Costs vary significantly by location, specification and project complexity. London and South East rates are typically 20-30% higher. Always obtain at least two to three written quotes and use a contract such as the JCT Minor Works form for any project over £5,000.
Qualifications to look for
The FMB requires members to pass a site inspection and credit check and to abide by a code of practice. Members offer a deposit protection scheme. Not a regulatory requirement but the most useful quality indicator when choosing a general builder. Check membership at fmb.org.uk.
A CSCS card confirms health and safety competence and trade qualification. Expected on virtually all commercial and larger residential sites. A general builder without a CSCS card is a red flag on anything beyond very small domestic jobs.
NHBC (National House Building Council) registration is required for builders offering a Buildmark warranty on new homes. For extensions and refurbishments, some builders offer a 10-year structural warranty through providers such as LABC Warranty or Premier Guarantee.
How to find a reputable general builder
Related Calculators
Extension Cost Calculator Loft Conversion Cost Calculator Garage Conversion Cost CalculatorFrequently asked questions
Do I need a builder for a planning application?
No - you need an architect or designer for planning drawings. A builder is appointed once planning permission is granted and building work is ready to begin.
How do I know if a builder is reputable?
Check for FMB membership, ask for references on similar completed projects, check Companies House for trading history, use a contract such as the JCT Minor Works form, and never pay large sums upfront. A trustworthy builder will not pressure you to pay before work is complete.
Should I get three quotes for building work?
Yes - always get at least two to three comparable written quotes. The cheapest is not always best value. Make sure each quote covers the same scope of work so you are comparing like for like, and ask each builder to break down the cost by trade and materials.