Home/Trades/Builder

Plan it with a builder.

Extensions, loft conversions and renovations — itemised quotes from JCT-friendly builders in your area.

Where is the job?
✓ Vetted tradespeople✓ Free quotes✓ Quick turnaround
20,000+UK homeowners
50,000Quotes sent
More than a marketplace

Hire a builder. Without the regret.

You've read the costs. You've seen the timeline. Now lean on us to find a Trustmark/FMB builder — and stay in control of the project.

Instant
01 · Ask

Ask the AI about your build

Not sure if you need a builder, a structural engineer, or both? Describe the project — the AI tells you exactly who you need and in what order.

Free
02 · Read the brief

Walk in informed

JCT contracts, retention, deposit norms, Building Control checkpoints. The builder brief covers what most homeowners don't know to ask.

60 seconds
03 · Compare

Compare 3 builder quotes

Itemised quotes from up to 3 vetted local builders, FMB and insurance — so you compare like-for-like, not lump sums.

Ready when you are

Enter your postcode and get free quotes from local pros.

Get builder quotes
Top tips

Hiring a builder, without the regret.

Four moves that separate a smooth job from a nightmare.

Insist on a JCT contract.

For anything over £10k, a JCT Homeowner Contract sets out payment stages, dispute resolution and snagging windows. Don't accept a one-page invoice.

Hold 5% retention for six months.

Pay 95% on completion, 5% six months later. It funds snagging and gives you leverage when the boiler's flue is wrong in week three.

Never pay more than 10% upfront.

A 10% deposit is fair to lock the slot. Stage payments tied to milestones (DPC, watertight, plaster, snags) keep both sides honest.

Get the Party Wall Award first.

Within 3m of a neighbour's wall, you legally need a Party Wall Award. Skip it and they can stop the job — or sue after.

Costs & timeline

Know what it costs. Know when it ends.

Indicative UK ranges and a typical week-by-week schedule.

Cost range

By job type

Inc. VAT · 2026
Source: NMT quotes
Single-storey extensionMid-range, ex. VAT
£1.8k–£2.6k/m²
Double-storey extensionCheaper per m² than single
£1.5k–£2.2k/m²
Internal wall removalInc. RSJ + plastering
£1.2k–£4k
Garage conversionStandard single garage
£12k–£25k
New build (mid-range)Excl. land
£2.1k–£3.2k/m²
Loft conversion (dormer)Inc. en suite
£45k–£85k
!

Quote spread is typically ± 18% — always get 3 quotes.

Timeline

25 m² single-storey extension · week by week

Typical
6 phases · 12 wk
W1
W2
W3
W4
W5
W6
W7
W8
W9
W10
W11
W12
Survey + drawings
Strip out + demo
Foundations + DPC
Frame + roof
1st + 2nd fix
Finishes + snags
!

Schedule slips on dependencies — pad each phase by 10–20% for real-world delays.

At a glance

The full Builder briefing.

Visual breakdown of costs, timelines and the questions you should be asking.

Infographic · Video
Infographic

Builder quick-view

PNG
Builder infographic guide
Video guide

Builder explained

MP4
About

Builder services in the UK.

Everything you need to know before hiring a builder.

Builders are the cornerstone of UK home improvement, specialising in the structural development, alteration, and maintenance of residential properties. From minor internal reconfigurations to complex multi-storey extensions and new builds, a professional builder provides the technical expertise and project management required to transform a house into a home.

Hiring a builder is often the first step in a major renovation. They coordinate various specialist trades, manage site safety, and ensure that every brick laid or steel beam installed meets the rigorous standards required for modern UK living.

What to Expect When Hiring a Builder

A professional builder offers a comprehensive range of construction services. While some focus on specific niches like loft conversions, most general builders handle a broad spectrum of work including:

  • Structural Alterations: Removing load-bearing walls and installing RSJs (steel beams) to create open-plan spaces.
  • Extensions & Conversions: Adding floor space through single or double-storey extensions, garage conversions, or annexes.
  • Groundworks: Excavating foundations, installing drainage systems, and preparing sub-bases.
  • Brickwork & Masonry: Expertly laying bricks, blocks, or stone to match existing property aesthetics.
  • Full Renovations: Stripping properties back to the shell and rebuilding internal layouts.

The process typically begins with a site visit and a review of your architectural drawings. Once a quote is agreed upon, the builder will establish a timeline, manage the delivery of materials, and liaise with Building Control officers throughout the various inspection stages.

Why Hire a Professional?

Structural work is high-stakes; errors can lead to property damage, safety risks, and legal complications. A professional builder ensures your project complies with UK Building Regulations, covering everything from structural integrity (Part A) to fire safety (Part B) and energy efficiency (Part L).

Beyond technical skill, professionals carry essential insurance, such as Public Liability and Employer’s Liability. They also understand the CDM 2015 regulations regarding site safety. Attempting large-scale structural work as DIY can invalidate your home insurance and make the property difficult to sell without the necessary completion certificates.

Typical Costs

Construction costs vary significantly based on your location in the UK, the complexity of the site, and the quality of finishes. Below are estimated costs for 2025/26, inclusive of VAT and standard labour rates.

Service Low £ High £ Notes
Single Storey Extension £1,800 £2,600 Per square metre (m2).
Double Storey Extension £1,500 £2,200 Per m2 (cheaper per m2 than single).
Internal Wall Removal £1,200 £4,000 Includes RSJ and plastering.
Garage Conversion £12,000 £25,000 Standard single garage.
New Build (Mid-range) £2,100 £3,200 Per m2, excluding land costs.

Price fluctuations are often driven by ground conditions (e.g., needing deeper foundations), site access restrictions, and the fluctuating cost of raw materials like timber and steel.

How to Choose the Right Builder

Finding a reliable builder requires due diligence to ensure your investment is protected. Look for the following markers of quality:

  • Accreditations: Check for membership in the Federation of Master Builders (FMB), TrustMark, or the Guild of Master Craftsmen.
  • References: Ask to see recently completed projects and, if possible, speak to previous clients about their experience with timelines and communication.
  • Insurance: Verify they have valid Public Liability insurance (minimum £2 million, though £5 million is preferred for larger jobs).
  • Written Contracts: Never rely on a handshake. Use a standard contract (like those from the FMB or JCT) that outlines payment milestones and the scope of work.

Questions to ask: How do you handle "extras" or changes to the plan? Who will be the daily point of contact on-site? Can you provide a detailed schedule of works?

Frequently Asked Questions

Do I need planning permission for all building work?

Not necessarily. Many smaller extensions and conversions fall under "Permitted Development" rights. However, all structural work must comply with Building Regulations, which is a separate process from planning permission.

Should I pay a deposit upfront?

A small deposit to secure a start date is common, but you should never pay for the entire job upfront. Establish a payment schedule based on completed milestones (e.g., foundations, wall plate, watertight stage).

What is the difference between a builder and a main contractor?

A builder often performs the physical work with a small team. A main contractor manages the entire project, hiring various subcontractors (plumbers, electricians, etc.) and taking full responsibility for the timeline and budget.

NEWAI Trade Assistant

Not sure if you need a
builder?

Describe the job in plain English. The AI asks a few smart questions, then tells you whether a builder is the right call, what it should cost, and what to ask before they start.

I'm planning a job. Should I be looking for a builder?
Sounds like a job for builder. Tell me what you're trying to do — I'll walk you through costs, timeline and what to ask before they start.
FREE QUOTES60 SECONDS
Expert guides

Tips & DIY help for builder projects.

VIEW ALL BUILDER GUIDES →

Property Maintenance / Repair

4 guides