House Extension Cost in Woking | 2026 Price Guide | Local Builders
When your Woking home no longer provides the space your family needs, an extension offers a practical solution. But before committing to a project, you need to understand realistic costs. Extension prices vary significantly based on size, specification, and complexity—what works for a modest rear extension in Knaphill differs considerably from a large wrap-around in Pyrford.
This guide provides honest, up-to-date pricing for house extensions across Woking in 2026, helping you budget effectively and avoid surprises once work begins.
Understanding Extension Costs
House extension costs are typically calculated per square metre, though final prices depend on numerous factors beyond simple floor area. In Woking and the surrounding area, expect to pay between £2,000 and £3,200 per square metre depending on extension type and specification.
This range covers construction costs including foundations, walls, roof, windows, doors, electrics, plumbing, plastering, and basic finishing. It doesn’t include kitchens, bathrooms, high-end flooring, or bespoke features—these add to your budget depending on your choices.
Let’s break down costs by extension type.
Single Storey Extension Costs
Single storey rear extensions remain the most popular choice for Woking homeowners. They create additional ground floor space for kitchens, dining areas, living rooms, or home offices without the complexity and cost of building upward.
Typical costs for single storey extensions in Woking:
- Small extension (15-20 sqm): £35,000-£55,000
- Medium extension (20-30 sqm): £50,000-£80,000
- Large extension (30-40 sqm): £75,000-£110,000
These figures assume mid-range specifications with quality materials and finishes. Budget builds at the lower end of the scale and premium specifications push costs higher.
Single storey extensions suit properties across Woking’s residential areas. The 1930s semis common in Horsell, St Johns, and Goldsworth Park often extend well at the rear, creating spacious kitchen-diners that transform family life. Modern estates in Sheerwater and Maybury also accommodate single storey additions where plots allow.
Under permitted development rules, you can typically extend 3 metres from the original rear wall for attached houses or 4 metres for detached properties without planning permission. Larger extensions up to 6 or 8 metres may be possible through the prior approval process.
Double Storey Extension Costs
When you need both ground floor and first floor space, a double storey extension delivers better value per square metre than building single storey alone. Foundations, walls, and roof are shared between both floors, reducing the overall cost compared to two separate projects.
Typical costs for double storey extensions in Woking:
- Small extension (30-40 sqm total): £65,000-£95,000
- Medium extension (40-60 sqm total): £90,000-£135,000
- Large extension (60-80 sqm total): £125,000-£180,000
Double storey extensions almost always require planning permission. The application process takes around eight weeks and involves assessment of your extension’s impact on neighbours, including overshadowing and privacy considerations.
Properties in West Byfleet, Byfleet, and Pyrford often suit double storey extensions, with generous plots providing space for substantial additions. The family homes common across these areas benefit from extra bedrooms and bathrooms above enlarged ground floor living spaces.
Wrap-Around Extension Costs
Wrap-around extensions combine rear and side extensions into one L-shaped structure, maximising the space gained from your project. This approach suits corner plots or properties where both side and rear extension are feasible.
Typical costs for wrap-around extensions in Woking:
- Medium wrap-around (35-50 sqm): £80,000-£125,000
- Large wrap-around (50-70 sqm): £115,000-£170,000
Wrap-around extensions create the largest ground floor transformations, often doubling kitchen and living space. They require careful design to maintain natural light to existing rooms and ensure the extension complements your home’s proportions.
Detached properties across Horsell, Hook Heath, and Woking’s more spacious residential streets often accommodate wrap-around designs. Semi-detached homes can also extend in this way where side access and plot width allow.
Side Return Extension Costs
Many Victorian and Edwardian properties feature narrow side returns—the passage running alongside the kitchen toward the rear garden. Extending into this wasted space adds valuable width without taking significant garden area.
Typical costs for side return extensions in Woking:
- Small side return (8-12 sqm): £28,000-£45,000
- Combined side and rear (15-25 sqm): £45,000-£75,000
Side return extensions work particularly well on older properties around Woking town centre and in areas with Victorian and Edwardian housing stock. Combined with a modest rear extension, they transform narrow galley kitchens into generous open-plan spaces.
What Affects Extension Costs?
Beyond basic size, several factors influence your final price.
Foundations
Ground conditions determine foundation requirements. Woking’s mix of clay and sandy soils presents varying challenges. Clay soils common across parts of Horsell and St Johns may require deeper foundations to account for shrinkage and movement. Trees near your extension can also affect foundation design, particularly on clay soils where root activity influences ground moisture.
Poor ground conditions or proximity to trees can add £5,000-£15,000 to foundation costs compared to straightforward sites.
Specification and Finishes
Basic specifications with standard windows, simple roofing, and basic internal finishes sit at the lower end of cost ranges. Higher specifications including bi-fold doors, roof lanterns, underfloor heating, and quality flooring push costs toward the upper end.
A basic rear extension might include standard patio doors, painted plaster walls, and laminate flooring. A premium version could feature large-format bi-fold doors, vaulted ceilings with skylights, engineered oak flooring, and bespoke joinery. The size might be identical, but costs differ by £20,000 or more.
Structural Complexity
Extensions involving structural alterations to your existing property—removing internal walls, installing steel beams, or reconfiguring layouts—add cost beyond the extension itself. Budget £3,500-£9,000 for removing a typical load-bearing wall including steel beam installation.
Access and Site Constraints
Difficult access affects costs. If materials cannot reach your garden easily, manual handling or specialist equipment adds expense. Tight sites with limited space for storing materials also slow progress and increase labour costs.
Properties in Woking town centre or on narrow plots may face higher costs than those with straightforward access and space to work.
Professional Fees
Don’t forget to budget for professional fees:
- Architectural drawings: £1,800-£4,500
- Structural engineer: £600-£1,800
- Planning application (if required): £258 (current fee)
- Building regulations: £600-£1,200
- Party wall surveyor (if applicable): £800-£1,800 per neighbour
These fees add several thousand pounds to your project but are essential for compliance and quality results.
Kitchen and Bathroom Costs
If your extension includes a kitchen or bathroom, factor in fitting out costs separately from construction prices.
Kitchen fitting out: £10,000-£35,000+ depending on size and specification. This covers units, worktops, appliances, splashbacks, and installation.
Bathroom fitting out: £6,000-£18,000 including sanitaryware, tiling, and installation.
These costs sit on top of your extension build price, so a kitchen extension with mid-range kitchen fitting might total £80,000-£100,000 overall for a medium-sized single storey project.
Getting Accurate Quotes
Online guides provide useful starting points, but every property differs. The only way to get accurate pricing for your Woking extension is detailed quotations from experienced builders.
When comparing quotes, ensure each covers the same scope. Ask specifically:
- What’s included in foundation costs?
- Are structural works priced or provisional?
- What level of internal finishing is included?
- Are professional fees included or additional?
- What specification of windows and doors?
- Is VAT included?
Detailed quotations specifying exactly what’s included prevent surprises once work begins. Be wary of vague pricing—the cheapest quote often excludes elements others include.
Planning Your Extension Budget
Based on current Woking prices, here’s how to approach budgeting:
Entry level: Assume £2,000-£2,400 per square metre for basic specifications with standard finishes.
Mid-range: Budget £2,400-£2,800 per square metre for quality builds with good specifications.
Premium: Allow £2,800-£3,200+ per square metre for high-end specifications and bespoke features.
Add 10-15% contingency for unexpected issues—older properties particularly can reveal surprises once work begins. Factor in professional fees, and budget separately for kitchens, bathrooms, and any furniture or fittings you’ll need.
Is an Extension Worth the Investment?
Beyond the lifestyle benefits, extensions typically add value to Woking properties. A well-designed extension in a desirable area can add more value than it costs to build, though this depends on your property type, location, and local market conditions.
Even where value added roughly equals cost, you benefit from years of improved living space without paying estate agent fees, stamp duty, and moving costs you’d face when relocating to a larger property.
Next Steps
Understanding realistic costs helps you plan effectively and have informed conversations with builders. The next step is getting quotations specific to your property and requirements.
We build house extensions throughout Woking and the surrounding area, covering Horsell, St Johns, Knaphill, Goldsworth Park, Sheerwater, Maybury, Hook Heath, Byfleet, West Byfleet, Pyrford, and surrounding villages. Contact us to discuss your project and arrange a free, no-obligation quotation tailored to your property and requirements.
Planning an extension for your Woking home? Contact us for a free survey and detailed quotation.