House Extension
in Washington
Compare quotes from vetted Washington extension builders for single-storey, double-storey and rear extensions. Transparent pricing from £14,500. Free, no-obligation quotes — results in 24 hours.
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How Much Do House Extension Cost in Washington?
Real prices from completed projects in Washington 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 →Washington pricing note: North East England (Newcastle, Sunderland, Teesside) is one of the most affordable regions for building work, with costs running 10–15% below the national average. Excellent value for extensions and loft conversions. Prices shown are indicative ranges for Washington and North East. Always get at least 3 written quotes before committing to any builder.
House Extension Specialists Who Know Washington
Home renovation activity in Washington 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 Washington 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 Washington 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.
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What Washington Homeowners Say About Our House Extension Specialists
Wraparound extension on our 1970s detached in Washington. Internal opening to the original kitchen kept narrow to keep the cooker corner usable. Total £62400, 14 weeks end to end. Insurance copy of structural certificate filed with the deeds.
Compared four extension builders through BestBuilders for the Washington job. Highest-priced quote actually had the cheapest spec - the breakdown made it obvious. Permitted Development route confirmed via a Lawful Development Certificate before any digging. £70400 fitted, 12-week site programme. Snags fully closed within 21 days of handover.
A year in, the underfloor heating runs the new space at zero heating cost from solar. Builder we found via BestBuilders in Washington specced higher-grade glazing than we asked for - winter heating bills are noticeably lower. Total £85920. Insurance copy of structural cert filed with the deeds.
House Extension in Washington — FAQs
Plan Your house extension Project in Washington
Whether you're researching costs, checking planning rules, or comparing approaches before you commit, our editorial team has produced these guides to help Washington 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 Washington
We also connect homeowners with vetted house extension specialists in towns surrounding Washington.
Planning Your House Extension in Washington
Before you compare quotes, it's worth understanding the full UK price picture for house extension and how Washington 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 Washington
Find out whether your house extension needs planning permission in Washington, 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.