House Extension
in Southwark
Compare quotes from vetted Southwark extension builders for single-storey, double-storey and rear extensions. Transparent pricing from £21,500. Free, no-obligation quotes — results in 24 hours.
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How Much Do House Extension Cost in Southwark?
Real prices from completed projects in Southwark 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 →Southwark pricing note: Building costs in London are typically 30–40% above the national average, driven by higher labour rates, congestion charges, stricter planning requirements and premium material delivery costs. Inner London boroughs (Zones 1–2) command the highest rates. Prices shown are indicative ranges for Southwark and London. Always get at least 3 written quotes before committing to any builder.
House Extension Specialists Who Know Southwark
Southwark is one of the UK's most active home renovation markets. With a diverse range of properties across the area, from period homes to modern new builds, local builders need to be versatile, skilled, and reliable.
BestBuilders vets every builder in our Southwark network. We check for public liability insurance, relevant trade qualifications (CIOB, FMB, Gas Safe, NICEIC), and a minimum of five verified customer reviews before any builder can appear on our platform.
Whether you are planning a rear extension, a loft conversion, or a full kitchen renovation in Southwark, we will connect you with the right specialist within 24 hours. All quotes are free and there is no obligation to proceed.
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What Southwark Homeowners Say About Our House Extension Specialists
Steel-framed wraparound on our Victorian terrace in Southwark. New floor finished with engineered oak running through to the original house. Final invoice £116670 over 17 weeks. CIAT-registered architect on retainer for the planning drawings.
Compared four extension builders through BestBuilders for the Southwark job. Chose the design-and-build option for single-point accountability. Foreman walked the spec sheet through with us before any digger arrived. £79040 fitted including the new floor finishes. Building control sign-off straightforward, no comeback.
Two summers in, the threshold detail still drains perfectly with no puddling. Builder we found via BestBuilders in Southwark designed-in concealed downlights so the ceiling has no visible fittings. Total £57360. EPC went up two bands - the new envelope spec made a real difference.
House Extension in Southwark — FAQs
Plan Your house extension Project in Southwark
Whether you're researching costs, checking planning rules, or comparing approaches before you commit, our editorial team has produced these guides to help Southwark 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 Southwark
We also connect homeowners with vetted house extension specialists in towns surrounding Southwark.
Planning Your House Extension in Southwark
Before you compare quotes, it's worth understanding the full UK price picture for house extension and how Southwark 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 Southwark
Find out whether your house extension needs planning permission in Southwark, 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.