10 Things to Know Before Building a Kitchen Extension | Chichester
A kitchen extension can transform how your family uses your home, creating a stunning open-plan space that becomes the heart of your property. Across West Sussex, from Chichester to Bognor Regis, homeowners are extending their kitchens to create modern living spaces that combine cooking, dining, and family areas in light-filled environments.
However, building a kitchen extension is a significant investment requiring careful planning and consideration. This guide reveals ten essential things every West Sussex homeowner should know before starting their kitchen extension project. Whether you’re in a Victorian terrace near Chichester Cathedral, a semi-detached home in Bognor, or a detached property in the South Downs villages, these insights will help you plan successfully.
From understanding costs and planning requirements to choosing materials and managing the build, we’ll cover everything you need to make informed decisions and achieve the kitchen extension of your dreams.
1. Understand the True Cost of Your Kitchen Extension
Kitchen extensions in West Sussex typically cost between £1,800 and £2,500 per square metre, but understanding the full financial picture is crucial for realistic budgeting.
Standard Extension Costs:
A typical 4m x 4m (16m²) single-storey kitchen extension costs £28,800 to £40,000 including all structural work, glazing, roofing, and basic finishes. A larger 5m x 6m (30m²) extension costs £54,000 to £75,000. These prices cover groundworks and foundations, brickwork and structural steelwork, roofing with insulation, bi-fold or sliding doors, windows, first-fix electrics and plumbing, plastering and making good, but exclude kitchen units and appliances.
Hidden Costs to Budget For:
Many Chichester homeowners underestimate additional expenses. Planning permission costs £258 for householder applications if required. Building regulations fees range from £800 to £1,500. Structural engineer fees cost £500 to £1,200 for calculations and site inspections. Architect or design fees add £1,500 to £4,000 depending on complexity.
Kitchen Installation Costs:
Your extension creates the space, but fitting the kitchen is separate. Budget £5,000 to £25,000+ depending on specification. Budget kitchens from DIY stores cost £5,000 to £10,000 fitted. Mid-range kitchens from specialist suppliers cost £12,000 to £20,000. Premium bespoke kitchens exceed £25,000 easily.
Specification Upgrades:
Standard costs assume basic specifications. Premium bi-fold doors with slim frames add £3,000 to £8,000. Roof lanterns or skylights add £2,500 to £6,000. Underfloor heating costs £75 to £100 per square metre. High-specification finishes and materials increase costs by 15-25%.
West Sussex Regional Variations:
Chichester city centre and South Downs villages tend toward the higher end of cost ranges due to access challenges and conservation area requirements. Coastal towns like Bognor Regis and Littlehampton typically sit mid-range. Rural locations may incur additional travel charges from builders.
Always obtain detailed written quotations from multiple Chichester builders, ensure quotes include all work required, verify what’s included and excluded, and allow 10-15% contingency for unexpected issues.
2. Know Your Planning Permission Requirements
Understanding whether your kitchen extension needs planning permission saves time, money, and frustration.
Permitted Development Rights:
Many kitchen extensions fall under permitted development, meaning no planning application is required. Generally, single-storey rear extensions up to 3 metres (attached houses) or 4 metres (detached houses) from the original rear wall are permitted. Extensions mustn’t exceed 4 metres in height. The eaves height can’t exceed 3 metres. Extensions cannot cover more than 50% of land around the original house.
When Planning Permission is Required:
Several scenarios require formal planning applications. Properties in conservation areas (including much of central Chichester) have restricted permitted development rights. Listed buildings always require both planning permission and listed building consent. Extensions exceeding permitted development size limits need permission. Side extensions and wraparound extensions typically require applications. Properties where permitted development rights have been removed require permission.
Chichester District Council Considerations:
Chichester has unique planning considerations. The historic city centre has multiple conservation areas with strict requirements. Properties near Chichester Cathedral face additional scrutiny. South Downs National Park has different planning policies. Coastal areas have specific design guidelines.
The Planning Process:
Planning applications to Chichester District Council take 8 weeks for determination. Pre-application advice costs £150-£300 but helps identify issues early. Neighbour consultations are part of the process and can delay decisions. Conservation area applications may require heritage statements. Refusals can be appealed but add significant delays.
Building Regulations:
Even if planning permission isn’t required, building regulations always apply. These cover structural safety, fire safety, insulation and energy efficiency, drainage and waste, ventilation, and electrical safety. Building control approval is separate from planning and typically costs less and processes faster.
Work with experienced Chichester builders who understand local planning requirements and can advise on whether your specific project needs permission.
3. Choose the Right Extension Type for Your Property
Kitchen extensions come in several configurations, each suited to different properties and needs.
Single-Storey Rear Extension:
The most popular choice creates additional ground-floor space behind your existing kitchen. Typically 3-6 metres deep and full-width of the property, these extensions suit terraced, semi-detached, and detached homes. They’re often permitted development, minimizing planning complications. Costs are lower than double-storey options at £1,800-£2,200 per square metre. Modern designs incorporate large glazed areas connecting to gardens.
Side Return Extension:
Common on Victorian and Edwardian terraced houses, side return extensions utilize the narrow side passage. They typically add 2-3 metres width to your kitchen, dramatically opening up the space. Combined with removing internal walls, they create stunning open-plan areas. Side returns in Chichester’s older properties often cost £15,000-£25,000 for the structural work.
Wraparound Extension:
Combining rear and side extensions creates maximum space and transformation. These substantial projects require planning permission but deliver impressive results. Wraparound extensions suit corner plots or properties with substantial side access. Costs range from £60,000 to £120,000+ depending on size. The result is a completely reconfigured ground floor with extensive kitchen-dining-living space.
L-Shaped Extension:
Extending both rearward and to one side in an L-shape suits detached and semi-detached properties. These extensions work well on corner plots and provide flexible internal layouts. They create distinct zones for cooking, dining, and living while maintaining connection. L-shaped extensions typically cost more per square metre due to additional external walls but deliver impressive results.
Orangery-Style Extension:
Featuring brick pillars with glazed sections between them and a roof lantern, orangeries suit period properties beautifully. They’re particularly appropriate for conservation areas where full-glass modern extensions might be rejected. Orangeries cost more than standard extensions—budget £2,500-£3,500 per square metre. They provide character while delivering light-filled spaces.
Consider your property type, available space, budget, and how you’ll use the extended kitchen when choosing which extension type suits your West Sussex home best.
4. Design for Natural Light and Garden Connection
The best kitchen extensions maximize natural light and create seamless connections to gardens—essential for West Sussex’s climate.
Glazing Options:
Bi-fold doors remain the most popular choice, folding completely back to open the kitchen to gardens. They cost £3,000-£8,000 depending on size and specification. Sliding doors offer sleek, modern aesthetics with large glass panes. They’re slightly cheaper than bi-folds at £2,500-£6,000. French doors are the traditional option, budget-friendly at £1,500-£3,000 but providing less opening flexibility.
Roof Lights and Lanterns:
Roof lights flood extensions with natural light from above. Fixed Velux-style rooflights cost £800-£1,500 each. Roof lanterns—larger glazed structures—cost £2,500-£6,000 depending on size. They create stunning architectural features while maximizing daylight. Some Chichester extensions combine bi-fold doors with roof lanterns for exceptional brightness.
Window Positioning:
Side windows in extensions provide additional light and ventilation. Position windows to avoid overlooking neighbors—important in West Sussex’s often-close-packed housing. High-level windows maintain privacy while admitting light. Corner glazing creates contemporary aesthetics and brightness.
Orientation Considerations:
South-facing extensions receive maximum sunlight but can overheat in summer. Specify solar-control glazing or external blinds. North-facing extensions stay cooler but need maximum glazing for adequate light. East-facing extensions enjoy morning sun—ideal for breakfast areas. West-facing extensions get afternoon and evening sun—perfect for dinner preparation and entertaining.
Internal Layout:
Position cooking zones away from main glazed areas to avoid glare on reflective surfaces. Place dining tables near glazed walls to enjoy garden views. Create circulation space that doesn’t obstruct views or access to doors. Consider how natural light flows through to adjacent rooms when removing walls.
West Sussex’s climate provides good natural light most of the year. Design your extension to maximize this asset, creating bright, welcoming spaces that feel connected to gardens and outdoor areas.
5. Understand Structural Requirements
Kitchen extensions involve significant structural work requiring careful planning and professional expertise.
Foundation Requirements:
Extensions need proper foundations typically 900mm-1200mm deep depending on ground conditions. West Sussex has varied geology—clay soils around Chichester require deeper foundations than sandy coastal areas. Building control officers inspect foundations before allowing work to continue. Poor foundations cause cracking, movement, and expensive remedial work later.
Removing Load-Bearing Walls:
Creating open-plan spaces usually requires removing walls between existing kitchen and dining rooms. Load-bearing walls support the structure above and need steel beams (RSJs) to replace them. Structural engineers calculate required beam sizes—typically 150mm-300mm deep depending on span and load. Beam installation requires temporary support while removing walls and positioning steel. Making good after beam installation includes boxing in steelwork and plastering.
Building Regulations Compliance:
Extensions must meet current building regulations including structural stability, fire safety between properties, insulation achieving U-values of 0.15-0.18 W/m²K for walls and roofs, ventilation providing adequate air changes, drainage connecting to existing systems properly, and electrical work to Part P requirements.
Party Wall Considerations:
If building on or near boundaries with neighbors, Party Wall Act procedures may apply. You must serve party wall notices on affected neighbors. Neighbors can appoint surveyors to agree on how work proceeds. Party wall agreements protect both parties’ interests. Costs typically run £700-£1,500 per neighbor for surveyor fees. Many Chichester extensions in terraced areas require party wall agreements.
Professional Input:
Structural engineers are essential for calculating beam sizes and foundation requirements, producing drawings for building control, and conducting site inspections during construction. Their fees (£500-£1,200) represent money well spent ensuring structural safety and building control compliance.
Choose Chichester builders experienced with structural work who coordinate effectively with engineers and building control officers.
6. Plan Your Kitchen Extension Timeline
Understanding realistic timescales helps you plan around the inevitable disruption.
Pre-Construction Phase (6-16 weeks):
Design and planning take time before any building work begins. Initial design and quotations require 2-4 weeks. Planning permission, if required, adds 8-12 weeks. Building regulations approval takes 2-3 weeks. Structural engineer input adds 2-4 weeks. Schedule all these sequentially, and pre-construction easily takes 3-4 months for projects requiring planning permission.
Construction Phase (8-14 weeks):
Actual building timescales depend on extension size and complexity. Small extensions (3m x 3m) take 8-10 weeks. Medium extensions (4m x 5m) require 10-12 weeks. Large extensions (5m x 6m+) need 12-14 weeks. Wraparound extensions can take 14-18 weeks.
Week-by-Week Breakdown:
Weeks 1-2: Groundworks and foundations—excavation, concrete, and initial brickwork below ground. Weeks 3-5: Brickwork to full height—structural steelwork installation if removing walls. Weeks 6-7: Roofing structure and covering—windows and door installation. Weeks 8-9: First fix—electrical wiring, plumbing, and heating installation. Weeks 10-11: Insulation, plastering, and making good. Weeks 12-13: Second fix—electrics, plumbing completed, decorating. Week 14: Snagging and final touches.
Seasonal Considerations:
Building in West Sussex winters means potentially slower progress due to weather, concrete taking longer to cure, and bricklaying interrupted by rain and frost. Summer building offers faster progress, better weather for groundworks, and easier concrete curing, but builders are busier with potentially longer wait times.
Kitchen Installation:
After the extension completes, kitchen installation takes 1-2 weeks for standard kitchens or 3-4 weeks for bespoke installations. Add another week for tiling and final finishing.
Living Arrangements:
Most Chichester families remain at home during extensions. Expect noise and dust, particularly when removing walls. Kitchens remain partially functional in most cases, though temporary kitchen facilities help. The connection point between extension and existing house creates security and weather-tightness challenges for a few days.
Plan for realistic timescales and build in contingency time. Weather delays, material delivery issues, or unexpected structural problems can extend schedules by 2-4 weeks.
7. Choose Quality Materials and Specifications
Material choices significantly impact your extension’s appearance, performance, and longevity.
Brickwork and External Finishes:
Match existing brickwork for cohesive appearance—particularly important in conservation areas. West Sussex has distinctive brick types; period properties often feature red brick or local stone. New bricks should complement rather than exactly match (perfect matching is difficult and expensive). Render is a modern alternative—textured or smooth finishes in various colors. It costs less than brickwork and suits contemporary designs. Timber cladding creates contemporary aesthetics but requires regular maintenance in West Sussex’s damp climate.
Roofing Options:
Pitched roofs matching your existing house look traditional and often receive easier planning approval. Tiles should match existing roofing. Flat roofs with roof lanterns create modern aesthetics and maximize internal height. Modern materials like EPDM rubber or GRP fiberglass provide 20-30 year lifespans. Ensure adequate insulation—flat roofs need 150-200mm for building regulations compliance.
Windows and Doors:
UPVC offers affordability and low maintenance with good thermal performance, costing £3,000-£6,000 for typical bi-fold sets. Aluminum provides slim frames maximizing glass area, modern aesthetics, and durability, but costs more at £5,000-£10,000. Timber offers traditional appearance suitable for period properties, requires maintenance, and costs £6,000-£12,000.
All options should feature thermally broken frames and high-performance glazing. Specify toughened or laminated glass in glazed doors and low-level glazing for safety. Consider built-in blinds within glazing units for low-maintenance shading.
Insulation and Energy Efficiency:
Building regulations require U-values of 0.15 W/m²K for walls (typically 100mm+ cavity insulation) and 0.15 W/m²K for roofs (typically 150-200mm insulation). Better insulation reduces heating costs and improves comfort. Consider underfloor heating in extensions—it’s efficient, provides even warmth, and eliminates radiators freeing wall space.
Flooring:
Extension floors must match existing kitchen levels or step down slightly. Underfloor heating works with tiles, stone, engineered wood, and vinyl. Large-format tiles (600mm x 600mm or larger) suit modern extensions and work excellently with underfloor heating. Engineered wood provides warmth and works with underfloor heating (solid wood doesn’t). Luxury vinyl offers waterproofing, durability, and affordability.
Discuss material specifications with your Chichester builder early. Quality materials cost more initially but provide better performance, appearance, and longevity.
8. Select the Right Builder for Your Project
Choosing your builder is one of the most important decisions affecting your extension’s success.
What to Look For:
Seek established Chichester builders with proven local experience, portfolio of similar projects you can view, and references from recent West Sussex clients you can contact. Verify proper insurance including public liability (£5-10 million minimum) and employer’s liability. Ensure building guarantee schemes membership like FMB, Checkatrade, or TrustMark registration.
Red Flags to Avoid:
Be wary of builders who request large upfront payments (deposits shouldn’t exceed 10-20%), provide vague quotations without detailed breakdowns, lack proper insurance documentation, cannot provide references or previous work examples, or pressure you to make quick decisions.
Getting Quotations:
Obtain at least three detailed written quotations from reputable Chichester builders. Quotations should specify all work included, materials to be used with specifications, payment schedule clearly broken down, timescale from start to completion, and what’s excluded (like kitchen units, flooring, decorating).
Questions to Ask:
How many similar extensions have you completed in West Sussex? Can I visit a current or recent project? Who will manage my project day-to-day? What happens if problems arise or delays occur? How do you handle variations to the quoted work? What guarantees or warranties do you provide?
Contract Essentials:
Always work with written contracts specifying all work to be completed, total cost and payment schedule, start and completion dates, specifications for all materials, procedures for handling variations and additional work, and dispute resolution procedures.
Communication and Project Management:
Good builders communicate regularly with updates, attend site promptly when issues arise, coordinate trades effectively so work flows smoothly, protect your property and maintain clean sites, and resolve problems proactively and professionally.
Local Knowledge Matters:
Chichester builders understand local planning requirements, know which materials match West Sussex properties, have relationships with local suppliers for competitive pricing, and understand ground conditions and common issues in the area.
Take time choosing your builder. A good builder makes your extension experience positive; a poor one causes stress, delays, and potentially substandard work.
9. Prepare for Disruption and Living Arrangements
Kitchen extensions create inevitable disruption. Preparing properly minimizes stress.
Kitchen Functionality:
Your existing kitchen remains partially functional during most extensions, but expect limitations. Installation of steel beams requires kitchen access and power cuts for several hours. First-fix electrical and plumbing work disrupts services temporarily. The connection point between extension and existing house means exposure to weather and dust for 2-3 days.
Temporary Kitchen Solutions:
Many Chichester families set up temporary kitchens in dining rooms or utility rooms. Essentials include a microwave, kettle, and toaster for basic meals, temporary sink if possible (or bathroom basin for washing up), small fridge or cool box for essential storage, and portable hobs or slow cookers for cooking. Some families eat out more during extensions or use meal delivery services.
Dust and Noise:
Expect significant dust when cutting through walls to connect the extension, chasing walls for electrical cables and pipes, and removing internal walls for open-plan layouts. Noise occurs from power tools, particularly breaking through walls, excavation equipment during groundworks, and general building activity from 8am-5pm weekdays.
Protecting Your Home:
Good builders protect adjacent rooms with plastic sheeting during dusty work, protect floors with hardboard or carpet film, and use dust extraction equipment when cutting. Homeowners should remove or protect valuable items in adjacent rooms, seal gaps under doors with draft excluders to limit dust spread, and plan to decorate rooms adjacent to building work after completion.
Garden Access and Storage:
Builders need garden access for materials, equipment, and waste removal. Expect garden disruption for the extension footprint plus working area. Protect prized plants and garden features. Builders typically use part of your garden for material storage—skips for waste, stacks of bricks and blocks, and cement mixing areas.
Security Considerations:
During connection between extension and existing house, security is temporarily compromised. Good builders secure openings overnight with boarding, coordinate this work for shortest possible duration, and ensure your home remains secure and weathertight. Consider additional security measures if you’re away during critical phases.
Staying Elsewhere:
Some families choose to stay with relatives or rent temporary accommodation during the worst disruption phases. This might be worthwhile when removing major walls to connect extension and existing house, during several days of very dusty or noisy work, or if you have young children or work from home.
Disruption is temporary. Focus on the stunning kitchen extension you’ll enjoy for decades.
10. Future-Proof Your Investment
Design your kitchen extension with future needs in mind to maximize longevity and value.
Electrical Planning:
Install substantially more sockets than you currently need—future appliances and gadgets will fill them. Include USB charging points in convenient locations. Specify network cable points for reliable internet connectivity. Consider provisions for future smart home technology. Install dedicated circuits for high-power appliances like American-style fridge-freezers or range cookers.
Plumbing Considerations:
Specify good water pressure with upgraded pumps if necessary. Include hot water circulation if your boiler is distant. Install water filters or softeners if West Sussex’s hard water affects appliances. Provide waste connections in useful locations for future appliance changes.
Adaptable Layouts:
Create flexible spaces that can adapt as needs change. Kitchen-diners work for young families but adapt to formal dining as children grow. Open-plan works now, but could you add partitions later if needs change? Consider how spaces might be repurposed in 10-20 years.
Energy Efficiency:
Exceed minimum insulation standards if budget allows. Solar-ready roof orientation and structure for potential future panels. Underfloor heating provides efficient warmth and works well with heat pumps. High-performance glazing reduces heat loss and improves comfort.
Build Quality:
Don’t compromise on structural work, damp-proofing, or waterproofing. Quality materials last longer and perform better. Proper ventilation prevents condensation and moisture problems. Good drainage prevents water pooling around foundations.
Property Value:
Well-executed kitchen extensions typically add 10-15% to property values in West Sussex—often exceeding the extension cost. Poor-quality extensions add less value and may deter buyers. Extensions requiring significant work to address building regulation non-compliance might actually reduce saleability.
Permissions and Documentation:
Obtain and keep all building control completion certificates—essential for future sales. Keep all structural calculations and engineering drawings. Maintain guarantees for materials and workmanship. Photograph the build process for records.
Maintenance Access:
Ensure access to services like boilers, stopcock, and consumer units remains reasonable. Plan maintenance access to roof gutters and exterior walls. Don’t build in future maintenance headaches.
Think beyond immediate needs. A well-planned kitchen extension serves your family for decades and significantly enhances your West Sussex property’s value and appeal.
Conclusion
Building a kitchen extension in West Sussex is a significant but rewarding investment. Understanding costs, planning requirements, design principles, structural necessities, and choosing the right builder ensures your project succeeds.
Chichester and surrounding West Sussex areas present unique considerations including conservation areas and listed buildings, South Downs National Park planning policies, varied ground conditions affecting foundations, and coastal climate influencing material choices.
Take time planning your extension properly. Obtain multiple quotations from reputable local builders. Don’t compromise on structural work or building regulations compliance. Design for natural light and garden connection. Future-proof your investment with quality materials and adaptable layouts.
The result—a stunning kitchen extension that becomes your home’s heart, provides space for modern family living, connects beautifully to gardens, and adds substantial value to your West Sussex property.
Ready to start your kitchen extension project? Contact our experienced Chichester builders today for free consultations and detailed quotations.