London Extension & Planning Advice
Expert guidance on London home extensions, planning permission, costs, and building regulations. Written by architects with data from 80+ completed projects.
Party Wall Agreement London 2026: Costs, Process & Surveyor Fees
Complete guide to party wall agreements in London 2026. Surveyor fees £750–£1,800 per neighbour (you pay both). Process takes 2–4 months. Required for ~95% of London extensions.
Extension Size Cost Guide London 2026: 3m, 4m, 5m & 6m Prices
How much does a 3m x 5m extension cost in London? Full size-by-size breakdown inc VAT. 3mx5m £45k-£70k, 4mx5m £60k-£92k, 6mx6m £108k-£165k. Planning rules by depth included.
London Extension Costs 2026: Complete Pricing Guide
Updated 2026 extension costs from real London projects. £3,200-£4,600 per m², single-storey £60k-135k, two-storey £110k-290k. Borough breakdowns and cost calculator.
Side Return Extension London 2026: Costs, Planning & Design Guide
Side return extension costs London 2026 inc VAT: 1.2m×8m £52k–£90k structure, £70k–£130k all-in with kitchen and fees. Planning rules, RSJ beam costs, glass roof options and full 8–12 month timeline.
Extension Project Checklist 2025: Complete Step-by-Step Guide
Complete checklist for your London extension project. From initial ideas through to completion, every step you need to follow for a successful build.
Open Plan Kitchen Extension London 2025: Design, Costs & Layout Ideas
Complete guide to open plan kitchen extensions in London. Layout options, zoning strategies, structural considerations, and design tips for modern living.
Extension Lighting Design 2025: Natural Light, LEDs & Planning
Complete guide to lighting your extension. Natural light strategies, LED layouts, Part L requirements, and how to create the perfect atmosphere.
Structural Engineer Guide London 2025: When You Need One & Costs
Complete guide to structural engineers for London extensions. When you need one, what they do, typical costs £500-£2,000, and how to find a good one.
DIY vs Professional Extensions: What Can You Do Yourself in London?
Should you DIY your extension or hire professionals? Which tasks you can legally do yourself, what requires qualified tradespeople, and how to save money safely.
Prior Approval London 2025: When You Need It & How to Apply
Complete guide to prior approval in London. Larger home extensions, office to residential conversions, and other developments that need council notification.
How to Choose a Builder London 2025: Vetting, Contracts & Red Flags
Complete guide to finding and vetting builders in London. Get quotes, check references, understand contracts, and avoid cowboys. Protect your extension project.
Energy Efficient Extensions London 2026: Part L, Insulation & Heat Pumps
Part L 2021 U-values for extensions: walls 0.18 W/m²K, roof 0.15 W/m²K. Part O overheating rules, £7,500 heat pump grant, underfloor heating costs, solar PV payback and EPC improvement guide.
Energy Efficient Extensions London 2025: Part L, EPC & Sustainability
Build a sustainable extension in London. Part L 2021 requirements, EPC improvements, heat pumps, insulation standards, and how to reduce running costs.
Adding a Bathroom to Your Extension London 2025: Costs & Value Guide
Complete guide to adding bathrooms in London extensions. Ensuite costs £8,000-£15,000, adds 4-5% to property value. Plumbing, planning, and design considerations.
Basement Extension London 2026: Costs, Planning & Construction Guide
Basement extension costs London 2026 inc VAT: new basement £130k–£700k+, cellar conversion £30k–£90k. Borough planning policies, underpinning methods, waterproofing types and full 14–22 month timeline.
Garage Conversion London 2026: Costs, Planning & Complete Guide
Garage conversion costs London 2026 inc VAT: basic £18k–£30k, bedroom with en-suite £32k–£50k, full annex £40k–£70k. Planning rules, building regulations, and what use gives the best return.
Garage Conversion London 2025: Costs, Planning & Complete Guide
Complete guide to garage conversions in London. Costs from £15,000-£45,000, planning rules, building regulations, and how to maximise value. 4-8 week build time.
Greenwich Planning Refusals: Top 10 Reasons & How to Avoid Them
Data analysis of Greenwich planning refusals reveals 10 most common rejection reasons. 32% approval rate in conservation areas vs 68% elsewhere. Expert tips to avoid refusal.
Croydon Planning Refusals: Top 10 Reasons & How to Avoid Them
Data analysis of Croydon planning refusals reveals 10 most common rejection reasons. Suburban character issues account for 38%. Expert tips to avoid refusal.
Top 10 Fire Safety Consultants London 2025
Ranked list of London fire safety consultants for home extensions. Fire strategy reports from £350. Essential for loft conversions, open plan layouts, and Building Regs compliance.
Enfield Planning Refusals: Top 10 Reasons & How to Avoid Them
Data analysis of Enfield planning refusals reveals 10 most common rejection reasons. 24% relate to Green Belt, terracing effect issues account for 19%. Expert tips to avoid refusal.
Hammersmith & Fulham Planning Refusals: Top 10 Reasons & How to Avoid Them
Data analysis of H&F planning refusals reveals 10 most common rejection reasons. 67% conservation area coverage, Victorian terrace issues dominate. Expert tips to avoid refusal.
Newham Planning Refusals: Top 10 Reasons & How to Avoid Them
Data analysis of Newham planning refusals reveals 10 most common rejection reasons. Olympic regeneration zones, Victorian terraces. 92% prior approval success rate.
Top 10 Tree & Ecology Consultants London 2025
Ranked list of London arboriculturists and ecologists for home extensions. BS5837 surveys from £350. Essential for TPO trees, bat surveys, and planning compliance.
Top 10 Drainage Consultants London 2025
Ranked list of London drainage consultants for home extensions. Thames Water Build Over agreements, CCTV surveys from £250, soakaway design specialists.
Top 10 Traffic Consultants London 2025
Ranked list of London traffic consultants for home extensions. Transport statements, parking surveys, Construction Management Plans from £350.
Top Construction Challenges for London Home Extensions in 2025
Navigate the biggest obstacles facing London homeowners in 2025. Labour shortages, material costs up 12%, planning delays, and new building regulations explained.
Southwark Extension Guide: Planning, Costs & Conservation Areas 2025
48 conservation areas in Southwark. Side return £80k-120k, rear £70k-105k. Dulwich, Peckham, Camberwell planning. Victorian terraced costs.
Greenwich Extension Guide: Planning, Costs & World Heritage Site 2025
Maritime Greenwich World Heritage Site restrictions. 20 conservation areas. Side return £55k-90k, rear £65k-95k. Victorian/Edwardian terraced costs.
Islington Extension Guide: Planning, Costs & Rules 2025
40/42 conservation areas restrict permitted development. Side return £50k-110k, rear £60k-90k. Article 4 directions extensive. Typical terraced house extension costs.
Asbestos in London Extensions: Survey, Removal & Costs 2025
Pre-2000 houses 80% likely to contain asbestos. Survey £250-500, removal £1,500-3,500. Artex, floor tiles, roof sheets. HSE licensed contractor requirements.
Flat Roof vs Pitched Roof Extension London 2025
Flat roof £52k vs pitched £60k for 30m² extension. Flat: cheaper, easier permitted development, 20-year lifespan. Pitched: 50-90 years, less maintenance, better resale.
Extension Rejected? Planning Appeals Guide London 2025
34% success rate for householder appeals (2025 data). Written representation vs hearing costs, 10-16 week timelines, when to appeal. Real London examples.
Narrow Garden Extension London: Solutions for Small Gardens
Narrow garden extension solutions: 3-6m depth options, vertical design, minimal garden loss. 10-15m² extensions £35k-£60k.
Single vs Double Storey Extension London 2026: Which Is Better?
Single storey costs £45k–£165k inc VAT, often no planning needed. Two storey costs 50–70% more but doubles your floor area. Full cost, planning, and value comparison for 2026.
Orangery vs Extension London: Which Is Right for You?
Orangery vs extension comparison. Orangeries £30k-£80k (more light, £500-1000/m² cheaper), extensions £50k-£120k (better insulation). Planning permission, costs, ROI.
Wrap-Around Extension London: Complete Guide to L-Shaped Extensions
Wrap-around extensions combine side return + rear extension for maximum space. £75k-145k cost, planning permission needed, ideal for terraced houses.
Extension vs New Kitchen: Which Adds More Value?
£50k kitchen vs £75k extension ROI analysis. Kitchen adds 5-10%, extension adds 10-15%. Combined strategies and decision framework.
Hidden Costs of London Extensions: What Builders Don't Tell You
The real costs builders don't quote. Party wall £1-3k, asbestos £2-8k, drainage £3-15k, CIL charges. Add 15-25% to builder quotes for realistic budgets.
Extension ROI London 2025: How Much Value Will You Add?
Will your extension pay for itself? Data-driven ROI analysis. Single storey adds 10-15%, loft conversions 15%, two storey 15-25%. When extensions make financial sense.
Extension Financing London 2025: Loans, Mortgages & Payment Options
How to finance your London extension. Remortgage vs loans, further advance, staged payments. Compare costs for £50k-150k projects.
Permitted Development Rights London 2026: Complete Guide
Everything you need to know about building without planning permission in London. Borough-specific rules, Article 4 directions, and instant permitted development checker.
London Extension Costs 2025: Real Project Data
Actual extension costs from 5,000+ London projects. Ground floor, loft, side return costs by borough with free calculator.
Side Return Extension London: Complete Guide
Everything about side return extensions in London. Average costs £55k-85k, planning vs permitted development, kitchen integration, and real examples.
Loft Conversion London 2026: Costs, Types & Planning Guide
Loft conversion costs London 2026 inc VAT: Velux £50k–£65k, Dormer £60k–£80k, Mansard £80k–£120k. Planning rules, building regulations, party wall requirements and full timeline.
Rear Extension London 2026: Costs, Sizes & Planning Guide
Rear extension costs London 2026 inc VAT: 3m×5m £62k–£90k, 4m×5m £82k–£118k, 5m×6m £122k–£178k. Permitted development rules, prior approval scheme, design decisions and timeline.
Terraced House Extension London: Complete Guide
Extension options for London terraced houses. permitted development limits, party walls, side returns, wrap-around extensions, and cost breakdowns.
Conservation Area Extension London: Rules & Costs
Building in conservation areas. Restricted permitted development rights, planning requirements, materials, costs, and getting approval in 600+ London areas.
Building Regulations for Extensions 2026
Complete guide to building regs for extensions. Structural, fire safety, insulation, ventilation requirements. Costs and inspection stages.
Party Wall Agreement London: Complete Guide
Everything about Party Wall Act. When required, the process, costs (£700-1,500 per side), timeline, and handling neighbour disputes.
Two Storey Extension London: Costs & Planning
Two-storey extension guide. Costs £130k-150k, planning permission, design considerations, structural requirements, and timeline.
Semi-Detached House Extension London
Extension options for semi-detached houses. permitted development limits, rear and side extensions, loft conversions, costs, and one-side party walls.
Kitchen Extension London: Design & Costs
Kitchen extension guide. Open-plan layouts, bi-fold doors, lighting, costs £75k-120k. Rear, side return, and wrap-around options.
London Extension Timeline & Process 2025
Complete extension timeline from design to completion. 6-12 months typical. Planning, building regs, party wall, construction stages.
Architect vs Online Service: Which Is Best?
Honest comparison of traditional architects vs online services like Mayfair Studio. Costs, design quality, when to use each approach.