House Extension
in Horsham
Compare quotes from vetted Horsham extension builders for single-storey, double-storey and rear extensions. Transparent pricing from £19,500. Free, no-obligation quotes — results in 24 hours.
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How Much Do House Extension Cost in Horsham?
Real prices from completed projects in Horsham 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 →Horsham pricing note: South East England prices run 15–25% above the national average, particularly in Surrey, Kent and areas within commuter distance of London. Strong demand and limited contractor availability in peak season push costs higher. Prices shown are indicative ranges for Horsham and South East. Always get at least 3 written quotes before committing to any builder.
House Extension Specialists Who Know Horsham
Horsham has a thriving home improvement market driven by a strong local economy and a mix of Victorian terraces, post-war housing and contemporary developments. Finding the right builder is key to any successful project.
Every builder in our Horsham network is thoroughly vetted before joining BestBuilders. We verify insurance cover, check trade memberships with bodies such as the FMB and CIOB, and require a minimum of five real customer reviews.
From a small bathroom refurbishment to a major double-storey extension, our vetted Horsham builders cover the full range of residential projects. Request your free quotes today and compare options before making any decisions.
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What Horsham Homeowners Say About Our House Extension Specialists
Single-storey rear extension on our cottage in Horsham. 32m² extension with full-height glazing, underfloor heating throughout the new floor area. Came in £2480 under quote thanks to a simpler foundation. Building control sign-off on the first inspection.
Compared four extension builders through BestBuilders for the Horsham job. Quotes ranged from £42k to £71k - went with the £58k mid-tier on detail. Internal openings cut on a Saturday so the rest of the family was barely disturbed. £69600 fitted, 12-week site programme. Lived in throughout - dust kept to the construction zone, never the rest of the house.
Two years post-completion the extension still feels like part of the original house. Builder we found via BestBuilders in Horsham suggested moving the boiler to the new utility room - much quieter at night now. Total £72480. Estate agent valued the work at +£90k.
House Extension in Horsham — FAQs
Plan Your house extension Project in Horsham
Whether you're researching costs, checking planning rules, or comparing approaches before you commit, our editorial team has produced these guides to help Horsham 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 Horsham
We also connect homeowners with vetted house extension specialists in towns surrounding Horsham.
Planning Your House Extension in Horsham
Before you compare quotes, it's worth understanding the full UK price picture for house extension and how Horsham 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 Horsham
Find out whether your house extension needs planning permission in Horsham, 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.