House Extension Costs Gloucester 2026 | Complete Price Guide

Planning a house extension in Gloucester? Understanding the costs involved is crucial for budgeting your project effectively. Extension prices vary significantly based on size, specification, and location, but this comprehensive guide breaks down what you can expect to pay in Gloucester and surrounding areas during 2026.

Whether you’re considering a single-storey kitchen extension in Quedgeley, a double-storey addition in Longlevens, or a wraparound extension in Cheltenham, this guide covers all the costs you’ll encounter—from initial planning through to final completion.

Average House Extension Costs in Gloucester 2026

House extensions in Gloucester typically cost between £1,800 and £2,500 per square metre for standard specifications. This translates to the following approximate costs for common extension sizes:

Single-Storey Rear Extensions

Small (3m x 4m / 12m²): £21,600 – £30,000

• Perfect for compact kitchen extensions
• Includes basic finishes and standard glazing
• Suitable for terraced properties in city centre locations

Medium (4m x 6m / 24m²): £43,200 – £60,000

• Most popular size for kitchen-diners
• Room for dining table and living space
• Bi-fold doors and roof lanterns typically included

Large (5m x 8m / 40m²): £72,000 – £100,000

• Spacious open-plan family areas
• Premium glazing and high-specification finishes
• Underfloor heating and quality kitchen preparation

Double-Storey Extensions

Double-storey extensions offer better value per square metre as groundworks and foundations serve two floors:

Small (3m x 4m / 24m² total): £50,400 – £70,000

• Ground floor extension plus bedroom above
• Cost-effective way to gain two rooms
• Popular in Gloucester suburbs like Hucclecote

Medium (4m x 6m / 48m² total): £86,400 – £120,000

• Kitchen-diner below, master bedroom with en-suite above
• Significant value addition to properties
• Common across Barnwood and Abbeydale

Large (5m x 8m / 80m² total): £144,000 – £200,000

• Substantial family space on both floors
• Transforms property layout completely
• Adds 25-35% to property values in GL postcodes

Side Extensions

Side extensions vary considerably based on width and whether they’re combined with rear extensions:

Basic Side Extension (2m x 4m / 8m²): £14,400 – £20,000

• Widens existing rooms or creates utility space
• Common on semi-detached properties
• Minimal planning complications

Extended Side Return (2m x 6m / 12m²): £21,600 – £30,000

• Opens up ground floor considerably
• Popular combined with kitchen remodelling
• Frequent in Victorian terraces near city centre

Wraparound Extensions

Combining rear and side extensions for maximum impact:

Standard Wraparound (6m x 6m / 36m²): £64,800 – £90,000

• Dramatic transformation of ground floor
• Open-plan living throughout
• Usually requires planning permission

Large Wraparound (8m x 8m / 64m²): £115,200 – £160,000

• Complete ground floor reconfiguration
• Multiple rooms or vast open space
• Adds 30-40% to Gloucester property values

What’s Included in These Costs?

Standard extension costs in Gloucester include:

Groundworks & Foundations

• Site preparation and excavation
• Concrete foundations to building regulations depth
• Drainage connections and soakaways
• Damp-proof coursing

Structural Work

• Brickwork matching existing property
• Steel beam installations (RSJs)
• Structural engineer calculations and certification
• Load-bearing wall removals where applicable

Roofing

• Roof structure (timber or steel frame)
• Tiles or slate matching existing roof
• Insulation to current building regulations
• Guttering and fascias

Windows & Doors

• UPVC or aluminium frames (standard specification)
• Double glazing throughout
• Bi-fold or sliding doors for rear extensions
• Installation and sealing

First Fix

• Electrical wiring and consumer unit upgrades
• Plumbing for radiators and services
• Heating system extensions
• Ventilation installation

Second Fix

• Plastering to walls and ceilings
• Electrical sockets, switches and lighting
• Radiator installation
• Skirting boards and architraves

Finishing

• Floor screeding or timber floors
• Basic decoration (mist coat)
• Making good to existing house connections

Additional Costs to Consider

Beyond the basic construction, budget for these common extras:

Planning & Professional Fees

Planning Permission (Gloucester City Council): £258 – £462

• Householder application: £258
• Not required if within permitted development
• 8-week determination period standard

Building Regulations: £800 – £1,500

• Required for all extensions regardless of planning
• Includes plan checks and site inspections
• Gloucester City Council Building Control or Approved Inspector

Architectural Design: £1,500 – £4,000

• Measured survey of existing property
• Extension design and drawings
• Planning application preparation if needed

Structural Engineer: £500 – £1,200

• Calculations for steel beams and foundations
• Building regulations compliance certification
• Site inspections during construction

Party Wall Agreement: £700 – £1,500 per neighbour

• Required if building on boundary
• Surveyor fees for agreement preparation
• Common in terraced properties across Gloucester

Specification Upgrades

Premium Bi-Fold Doors: +£3,000 – £8,000

• Aluminium frames with slim sightlines
• Larger spans (4-6 panels)
• High-security locking systems

Roof Lanterns: +£2,500 – £6,000

• Fixed or opening roof lights
• Aluminium frames with self-cleaning glass
• Dramatically increases natural light

Underfloor Heating: +£75 – £100 per m²

• Electric or wet systems
• Warm floor throughout extension
• Energy-efficient heating solution

Kitchen Installation: £5,000 – £25,000+

• Not typically included in builder costs
• Wide range depending on specification
• Consider in overall budget planning

Internal Remodelling: £3,000 – £10,000

• Knocking through existing walls
• Creating open-plan layouts
• Additional structural steelwork

Regional Variations Within Gloucestershire

Extension costs vary slightly depending on location:

Gloucester City Centre (GL1): £2,200 – £2,500 per m²

• Higher costs due to access challenges
• Conservation area considerations
• Materials matching period properties

Gloucester Suburbs (GL2-GL4): £1,800 – £2,200 per m²

• Standard costs for most projects
• Areas like Quedgeley, Longlevens, Hucclecote
• Good access and fewer restrictions

Cheltenham: £2,000 – £2,500 per m²

• Slightly higher due to property values
• Conservation areas in town centre
• Premium materials often expected

Stroud & Forest of Dean: £1,700 – £2,100 per m²

• Rural locations may reduce costs slightly
• Potential for longer travel time charges
• Materials delivery considerations

Tewkesbury: £1,800 – £2,200 per m²

• Similar to Gloucester suburbs
• Some properties in conservation areas
• Good builder availability

Factors Affecting Your Extension Cost

Several variables impact the final price of your Gloucester extension:

Property Type & Location

Victorian and Edwardian properties often require careful material matching, increasing costs. Modern homes typically allow standard materials, reducing expenses. Properties in conservation areas or near listed buildings may face additional planning requirements.

Access is crucial—restricted access through narrow alleyways or properties without side access increases labour costs as materials must be carried further. City centre locations like Kingsholm typically cost more than suburban areas.

Ground Conditions

Gloucester sits on varied geology. Clay soils in some areas require deeper foundations, potentially adding £2,000-£5,000 to costs. Properties near the River Severn may need extra groundworks considerations. A site survey before quoting ensures accurate foundation costing.

Specification Level

Budget specifications using UPVC windows and standard finishes sit at the lower end of cost ranges. Mid-range projects include aluminium bi-folds and quality fixtures. Premium extensions feature large-format glazing, underfloor heating throughout, and high-end finishes, pushing costs toward £2,500+ per square metre.

Design Complexity

Simple rectangular extensions cost less than complex designs with multiple roof levels, unusual shapes, or extensive glazing. Flat roofs are typically cheaper than pitched roofs matching existing properties. However, pitched roofs often provide better long-term value and planning approval success.

Existing Building Work

Older Gloucester properties may require additional work during extensions. Rewiring existing electrics, upgrading heating systems, or addressing damp issues add costs but ensure your entire home meets modern standards.

Return on Investment: Property Value Increases

Extensions generally add more value than they cost, making them excellent investments:

Single-Storey Extensions: 10-15% property value increase

• A £50,000 extension on a £300,000 property adds £30,000-£45,000 value
• Breaks even or returns profit depending on specification
• Improves saleability significantly

Double-Storey Extensions: 15-25% property value increase

• A £100,000 extension on a £350,000 property adds £52,500-£87,500 value
• Strong positive return on investment
• Adds bedroom count, crucial for family buyers

Kitchen Extensions: 12-18% property value increase

• Modern kitchen-diners highly desirable in Gloucester market
• Appeals to young families and downsizers
• Quick sales when marketed well

These figures apply across Gloucester postcodes, though percentage increases are slightly higher in areas like Cheltenham and lower in more affordable locations. Quality of finish significantly impacts value—a well-executed extension returns far more than budget work.

Ways to Reduce Extension Costs

If your budget is tight, consider these cost-saving approaches:

Reduce Size: Dropping from 30m² to 24m² saves £10,800-£15,000 while still providing valuable space.

Simple Design: Rectangular extensions with straightforward roof structures cost 15-20% less than complex designs.

Standard Materials: UPVC instead of aluminium windows, standard tiles rather than slate, and simpler finishes reduce costs without compromising quality.

Project Timing: Building in winter months when builders are quieter may secure better rates, though weather can slow progress.

Do Finishing Work Yourself: Handling decoration, flooring, and final touches saves £3,000-£7,000 on typical extensions.

Value Engineering: Work with your builder to identify cost savings that don’t compromise structural integrity or longevity.

Financing Your Gloucester Extension

Most homeowners finance extensions through:

Savings: Ideal if you’ve planned ahead—no interest costs or approval processes.

Remortgaging: Releasing equity from your home typically offers the lowest interest rates. Gloucester property values have risen steadily, providing good equity for many homeowners.

Home Improvement Loans: Unsecured loans for £25,000-£50,000 are common for extensions. Compare rates carefully as they’re higher than mortgages.

Further Advance: Borrowing more from your existing mortgage lender keeps you with one lender and typically offers competitive rates.

Timeline Expectations

Understand the time commitment alongside financial investment:

Planning Phase: 2-4 weeks

• Initial consultations and design
• Quotation and contract agreement
• Faster if no planning permission needed

Planning Permission (if required): 8-12 weeks

• Application submission to Gloucester City Council
• Determination period
• Potential for neighbour consultations

Building Regulations Approval: 2-3 weeks

• Submit plans and calculations
• Approval before commencing work
• Inspections throughout construction

Construction:

• Single-storey extension: 8-12 weeks
• Double-storey extension: 12-18 weeks
• Wraparound extension: 14-20 weeks

Conclusion

House extensions in Gloucester offer excellent value, typically costing £1,800-£2,500 per square metre and adding 10-25% to property values. Whether you’re planning a compact kitchen extension in the city centre or a substantial double-storey addition in the suburbs, understanding these costs helps you budget accurately and make informed decisions.

Remember that the cheapest quote isn’t always the best value. Quality construction, experienced tradespeople, and proper project management ensure your extension stands the test of time and adds maximum value to your Gloucester home.

For an accurate quote tailored to your specific property and requirements, contact local Gloucester builders who can assess your home, discuss your vision, and provide detailed costings based on current 2026 prices.

Ready to start your extension project? Get in touch today for a free, no-obligation consultation and quotation for your Gloucester property.

---

Frequently Asked Questions

Do I need planning permission for an extension in Gloucester?

Many extensions fall under permitted development rights and don’t require planning permission. However, properties in conservation areas (including parts of central Gloucester), listed buildings, or extensions exceeding certain size limits need approval from Gloucester City Council. A builder or architect can assess your specific situation.

How much does a 4m x 6m kitchen extension cost in Gloucester?

A standard 4m x 6m (24m²) single-storey kitchen extension in Gloucester costs approximately £43,200 to £60,000, depending on specification, ground conditions, and finishes. This includes all structural work, glazing, first and second-fix services, but excludes kitchen units and appliances.

Is a double-storey extension cheaper per square metre?

Yes, double-storey extensions are more cost-effective per square metre because groundworks and foundations serve both floors. While the total project cost is higher, you gain twice the floor space for approximately 60-70% additional cost rather than double.

How long does building an extension take in Gloucester?

Single-storey extensions typically take 8-12 weeks from start to completion. Double-storey extensions require 12-18 weeks. Add 8-12 weeks if planning permission is needed. Building Regulations approval adds 2-3 weeks to the timeline.

Will an extension add value to my Gloucester home?

Yes, quality extensions typically add more value than they cost. Single-storey extensions add 10-15% to property values, while double-storey extensions add 15-25%. A £50,000 extension on a £300,000 property typically increases value by £30,000-£75,000 depending on size and specification.