House Extension
in Brentwood
Compare quotes from vetted Brentwood extension builders for single-storey, double-storey and rear extensions. Transparent pricing from £17,500. Free, no-obligation quotes — results in 24 hours.
- Vetted, insured house extension specialists in Brentwood
- Up to 3 free quotes — compare and choose with no pressure
- Transparent pricing, no hidden costs or surprise charges
- Work guaranteed, fully insured, trade-qualified contractors
How Much Do House Extension Cost in Brentwood?
Real prices from completed projects in Brentwood and the surrounding area. Costs vary by size, specification and access — use these as a starting guide, then get 3 free quotes for your specific project.
The most popular choice for UK terraces and semis. Adds a kitchen-diner or extra living space at ground level. Typically 3–5m deep, completed in 10–14 weeks.
Get quotes for this →Maximum space gain in a single build — adds a ground-floor room and a bedroom above. Strong ROI in most UK property markets. Requires full planning permission.
Get quotes for this →Ideal for terraced homes with a narrow side alley. Transforms a cramped kitchen into a full-width open-plan space. Often combined with a rear extension.
Get quotes for this →Costs depend on size, spec and access. The best way to know your exact price is to compare 3 quotes from vetted local specialists.
Get free quotes →Brentwood pricing note: Eastern England (Essex, Hertfordshire, Cambridgeshire, Suffolk, Norfolk) runs approximately 8–12% above the national average, influenced by proximity to London and strong demand in commuter towns. Prices shown are indicative ranges for Brentwood and Eastern. Always get at least 3 written quotes before committing to any builder.
House Extension Specialists Who Know Brentwood
Home renovation activity in Brentwood continues to grow year on year. The area's varied housing stock, from older stone-built properties to new-build estates, means there is always strong demand for skilled, experienced local builders.
Before any builder appears on our Brentwood platform, we carry out a full vetting check covering public liability insurance, trade qualifications, company registration and verified customer feedback. Only builders who pass every stage are listed.
Our Brentwood builder network covers extensions, loft conversions, kitchens, bathrooms, roofing, driveways and more. Get up to 3 free, no-obligation quotes within 24 hours and choose the builder that best fits your project and budget.
Start My Free Quote →How It Works
Every Builder We Recommend Is:
What Brentwood Homeowners Say About Our House Extension Specialists
Rear and side extension combined on our detached new-build in Brentwood. Added 28m² of open-plan kitchen-diner with bi-fold doors and a roof lantern. £75400 across 14 working weeks. Insurance copy of structural certificate filed with the deeds.
Compared four extension builders through BestBuilders for the Brentwood job. Selected on availability rather than price - we needed to start before winter. Crash deck during demolition kept the rest of the house liveable. £97150 over 18 working weeks, no surprise extras. Snags fully closed within 21 days of handover.
Six months later, no settlement cracks anywhere - foundations were clearly done right. Builder we found via BestBuilders in Brentwood specified Crittall-style steel doors over aluminium bi-folds - looks the part. Total £70800. Insurance copy of structural cert filed with the deeds.
House Extension in Brentwood — FAQs
Plan Your house extension Project in Brentwood
Whether you're researching costs, checking planning rules, or comparing approaches before you commit, our editorial team has produced these guides to help Brentwood homeowners make informed decisions about their house extension project.
House Extension Cost Guide
Detailed UK price ranges, regional adjustments and worked examples for house extension projects.
Read House Extension Cost Guide →All House Extension Specialists
Browse our nationwide network of vetted house extension contractors covering all 519 UK towns.
Browse House Extension Specialists →All Cost Guides
Compare prices across extensions, lofts, kitchens, bathrooms, roofing, driveways and solar projects.
View All Cost Guides →Planning your house extension project? Read these guides:
House Extension Near Brentwood
We also connect homeowners with vetted house extension specialists in towns surrounding Brentwood.
Planning Your House Extension in Brentwood
Before you compare quotes, it's worth understanding the full UK price picture for house extension and how Brentwood sits within it. The guides below cover average costs, what affects your quote, and how to choose a builder you can trust.
UK House Extension Cost Guide
Full price ranges, worked examples and the factors that move your quote — drawn from real project data across 519 UK towns.
Read the house extension cost guide →House Extension Across the UK
Browse house extension services nationwide, see what's typical in your region, and request quotes from any UK location.
Visit the UK house extension hub →Planning Permission for House Extension in Brentwood
Find out whether your house extension needs planning permission in Brentwood, what Permitted Development limits apply, and how rules differ in conservation areas, Article 4 zones, and listed-building settings.
Read the house extension planning rules →More homeowner resources: all UK building guides, cost guides, planning permission, comparisons, how-to guides and industry insights.