Find a Extension Builder in Chelmsford

Find trusted extension builder professionals in Chelmsford. TradeMatch connects you with vetted, insured local tradespeople. Average extension builder cost in Chelmsford: £15,000–£50,000. Compare up to 5 free quotes with escrow payment protection.

Compare free quotes from vetted tradespeople in the CM postcode area. Typical cost: £15,000–£50,000.

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Extension Builder professional working in Chelmsford

Quick answer

What does an extension builder do, and what does it cost in the UK?

An extension builder handles groundwork, structure, roof and finishing for a single- or double-storey home extension. UK 2026 typical cost: £1,500–£2,500 per m² (London: +30–40%). A 4×5m single-storey rear runs £30,000–£60,000. Most need Building Regs approval; some need full planning permission. Allow 10–14 weeks for single, 14–20 for double.

Why Choose TradeMatch for Extension Builder Services in Chelmsford?

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Verified Tradespeople

Every extension builder on TradeMatch has their identity, qualifications and trade body memberships checked before they can quote.

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Fully Insured

All extension builder professionals carry valid public liability insurance, verified by our team, protecting you and your property.

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Genuine Reviews

Read honest reviews from homeowners in Chelmsford who have hired through TradeMatch. No fake reviews, ever.

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Free Quotes

Post your job and receive up to 3 free, no-obligation quotes from local extension builder professionals. Compare and choose.

Verified Credentials

UK accreditations every extension builder in Chelmsford is checked against

Every tradesperson is verified against the UK accreditation bodies that matter for the work — before they can quote.

Read the full UK accreditations guide →

Extension builder vs general builder vs loft converter

JobExtension builderGeneral builderLoft converter
Single-storey rear extension✅ Recommended⚠️ Variable quality❌ Out of scope
Double-storey side return✅ Recommended⚠️ Variable quality❌ Out of scope
Loft conversion⚠️ Some⚠️ Variable quality✅ Recommended
Garage conversion✅ Yes✅ Yes⚠️ Sometimes
Internal renovation⚠️ Possible✅ Recommended❌ Out of scope

Use a builder who specialises in extensions for anything structural. A specialist coordinates planning, structural engineer, party-wall surveyor and Building Control on your behalf.

Average Extension Builder Costs in Chelmsford

Below are typical prices for common extension builder jobs in Chelmsford. Prices may vary depending on the complexity of work, materials used and access to your property. Overall typical cost range: £15,000–£50,000.

Job DescriptionLowAverageHigh
Small job£80£200£400
Medium job£300£700£1,500
Large job£1,000£2,500£5,000
Consultation/survey£50£100£250
Emergency callout£80£150£300

Prices shown are estimated UK averages for 2026 and may differ in Chelmsford. Get an accurate quote by posting your job on TradeMatch.

How do you hire a Extension Builder in Chelmsford?

1

Describe Your Job

Tell us what extension builder work you need in Chelmsford. Include any details about access, materials, or timing.

2

Receive Local Quotes

Get up to 3 free quotes from extension builder professionals based in the CM postcode area.

3

Compare & Hire

Read reviews from other Chelmsford homeowners, compare prices and hire with confidence.

Extension Builder workmanship in Chelmsford

Extension Builder terms explained — Chelmsford glossary

Permitted Development(PD)
A planning right that lets you extend without full planning permission inside set limits (e.g. 4m rear depth on a semi). Conservation areas and Article 4 Directions remove or restrict it.
Building Regulations(BR / BC)
The technical standards for structure, insulation, fire safety and ventilation. All extensions need Building Control sign-off, even when planning permission is not required.
Party Wall Act 1996(PWA)
The law governing work to walls shared with a neighbour. You must serve notice 1–2 months before excavating within 3m of a boundary or cutting into a party wall.
SAP Calculation(SAP)
Standard Assessment Procedure — the energy calculation submitted with most extension applications. Required to demonstrate Part L1A compliance.

Extension Builder in Chelmsford — FAQ

How much does a extension builder cost in Chelmsford?▾
Extension Builder costs in Chelmsford typically range from £15,000–£50,000. Chelmsford prices are 10–18% above UK average compared to the UK average. Post your job on TradeMatch to get free, personalised quotes from local extension builder professionals in Chelmsford.
How do I find a trusted extension builder in Chelmsford?▾
TradeMatch UK has vetted extension builder professionals in Chelmsford and across Essex. Each tradesperson is background-checked, insured and reviewed by real homeowners. Post your job free and compare up to 5 quotes from Chelmsford-based professionals. All payments are escrow-protected.
What qualifications should a extension builder in Chelmsford have?▾
A qualified extension builder should hold: Relevant trade qualifications, Public liability insurance. The relevant regulatory body is Relevant trade association. On TradeMatch, we verify these credentials for every extension builder in Chelmsford before they can quote on jobs.
How much does a extension builder charge per hour in Chelmsford?▾
Hourly rates for a extension builder in Chelmsford typically range from £80 to £400, depending on the job and experience level. Chelmsford rates are 10–18% above UK average. Many extension builder professionals prefer to quote per job rather than per hour — post your job on TradeMatch for accurate, fixed-price quotes.
Is it worth hiring a extension builder or doing it myself in Chelmsford?▾
For small cosmetic tasks you may be able to DIY, but for anything involving relevant trade qualifications it's safer and often cheaper long-term to hire a qualified extension builder. Incorrect work can void insurance, fail building inspections, or cause damage. Chelmsford homeowners on TradeMatch get free quotes to compare before deciding.
How quickly can I hire a extension builder in Chelmsford?▾
Most homeowners in Chelmsford receive their first quote within hours. For standard extension builder work you can typically have someone booked within 1–3 days. Emergency services may be available same-day depending on availability in the CM postcode area.
What guarantee should a extension builder offer in Chelmsford?▾
A reputable extension builder should offer a written guarantee of at least 12 months on labour. For larger projects, look for guarantees backed by Relevant trade association or an insurance-backed warranty. On TradeMatch, all payments are escrow-protected — you only release funds when the work meets your expectations.
How many quotes should I get for extension builder work in Chelmsford?▾
We recommend getting at least 3 quotes to ensure a fair price. TradeMatch lets you compare up to 5 free quotes from vetted extension builder professionals in Chelmsford. Don't automatically choose the cheapest — weigh up reviews, qualifications and the detail in each quote.
Are extension builder professionals on TradeMatch insured?▾
Yes. Every extension builder on TradeMatch UK carries public liability insurance as a minimum. For regulated trades, we also verify certifications including Relevant trade qualifications, Public liability insurance. All payments are escrow-protected for your peace of mind.
Do Chelmsford extension builder professionals on TradeMatch offer free quotes?▾
Yes. All quotes from extension builder professionals in Chelmsford on TradeMatch are completely free with no obligation. You only pay when you choose to hire, and payments are escrow-protected — funds are released only when you approve the work.
What are the hidden costs when hiring a extension builder in Chelmsford?▾
Common additional costs include: materials and delivery, skip hire or waste removal, parking permits (especially in Chelmsford city centre), VAT (if the extension builder is VAT-registered), and call-out fees for emergency work. Always ask for an itemised quote. On TradeMatch, you can compare detailed quotes side by side.
Can I get a extension builder at weekends in Chelmsford?▾
Many extension builder professionals in Chelmsford work weekends, though they may charge a premium of 10–30% for Saturday work and up to 50% more on Sundays. On TradeMatch, you can specify your preferred dates when posting a job — Chelmsford-based tradespeople who are available will quote accordingly.
What extension builder services are available in Chelmsford?▾
Extension Builder services available in Chelmsford include: Single Storey Extension, Double Storey Extension, Kitchen Extension. Post your specific job on TradeMatch to get quotes from Chelmsford professionals who specialise in the service you need.

Extension Builder Reviews in Chelmsford

Read reviews from homeowners who hired extension builder professionals through TradeMatch in Chelmsford and across Essex.

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Extension Builder Resources for Chelmsford

Extension Builder Costs in Chelmsford→Extension BuilderNear Me →All Extension BuilderLocations →Extension BuilderCost Guide →All Trades in Chelmsford→

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