House Extension
in Southend on Sea
Compare quotes from vetted Southend on Sea extension builders for single-storey, double-storey and rear extensions. Transparent pricing from £17,500. Free, no-obligation quotes — results in 24 hours.
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How Much Do House Extension Cost in Southend on Sea?
Real prices from completed projects in Southend on Sea 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 local specialists.
Get free quotes →Southend on Sea 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 Southend on Sea and Eastern. Always get at least 3 written quotes before committing to any builder.
House Extension Specialists Who Know Southend on Sea
Tell us about your house extension project once and up to three local specialists who cover Southend on Sea get in touch with quotes — free, with no obligation, and you choose who to hire.
Most firms quoting in Southend on Sea also travel to nearby Cambridge, St Albans and Grays. That matters because it widens the pool of Eastern contractors competing for your job, which usually sharpens the price.
On price, 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. Comparing three written quotes is the simplest way to see where your own Southend on Sea job sits inside that range.
Local facts: Southend-on-Sea
- Local planning authority: Southend-on-Sea Council
- Region: East of England
- Town-centre postcode district: SS1
- Average house price (Southend-on-Sea local authority, June 2026): £325,586 (+3.7% year on year) — detached £637,039, semi-detached £426,047, terraced £331,347, flats £197,719
Planning-authority, region and postcode data: ONS Postcode Directory (Open Government Licence). House prices: HM Land Registry UK House Price Index for the local authority (OGL). Member coverage is each member's own registered base and travel radius.
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House Extension in Southend on Sea — FAQs
Plan Your house extension Project in Southend on Sea
Whether you're researching costs, checking planning rules, or comparing approaches before you commit, our editorial team has produced these guides to help Southend on Sea 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 local 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:
Planning Your House Extension in Southend on Sea
Before you compare quotes, it's worth understanding the full UK price picture for house extension and how Southend on Sea 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 Southend on Sea
Find out whether your house extension needs planning permission in Southend on Sea, 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.