Planning guides & data

Hip to gable loft conversion London 2026: £52,500-£115,000 inc VAT. Permitted development volume limits, rear dormer combo, and LDC vs planning explained.

Velux loft conversion cost London 2026: £27,500-£70,000 inc VAT. Rooflight-only conversions, permitted development rules, and velux vs dormer compared.

Extending a Newham terrace? PD rights for pre-1919 terraces, the borough-wide HMO Article 4 direction, nine conservation areas, and typical 2026 extension costs.

Extending in Enfield? Permitted development, the borough-wide HMO Article 4 direction, 22 conservation areas, green belt coverage, and typical 2026 extension costs.

Extending in Westminster: 56 conservation areas covering over 76% of the city, around 11,000 listed buildings, the basement Article 4 direction, and premium-end 2026 costs.

Extending in Waltham Forest? London's most Article 4-covered borough explained: what the directions actually restrict, 16 conservation areas, CIL rates, and 2026 extension costs.

Bought or own a house split into flats without permission? Enforcement time limits after LURA 2023, POCA confiscation risk, and the lawful development certificate route explained.

Real HMO conversion costs in London. Light conversions £40k-75k, full en-suite conversions £90k-150k, fire safety, minimum room sizes, licensing fees by borough, and planning vs licensing explained.

Extending in London's most affordable borough: Becontree estate rules and the new 2026 Article 4 directions, borough-wide HMO restrictions, four conservation areas, and typical costs.

Refused under Class MA? The limited grounds councils can refuse on, resubmission with fixes, the six-month appeal route, when a full application beats Class MA, and a decision framework.

Article 4 directions explained in plain English: what they withdraw, immediate vs non-immediate directions, compensation rights, how to check if you are affected, and what happens if you ignore one.

Which London boroughs have Article 4 directions removing HMO permitted development rights, and what that means for C3-to-C4 conversions.

Full breakdown of what the free Mayfair Studio planning checker analyses: 10 national datasets, 32 London borough policies, 9m+ planning decisions, PD rights, Article 4, conservation areas, flood risk and more.

Exact PD size limits for every extension type - rear extensions, lofts, side extensions. Plus the Prior Approval scheme that allows 6m or 8m rear extensions without a planning application.

Decision framework for London homeowners. PD rules by extension type, conservation areas, Article 4 directions, and free instant check tool.

Compare extension costs across 15 London boroughs. Cost per m², conservation area risk, Article 4 zones, and planning approval rates - from £1,900/m² (Lewisham) to £3,800/m² (Kensington & Chelsea).

Loft conversion or rear extension? Full comparison: costs (£54k–£75k vs £40k–£65k), PD eligibility, value added, build times, and which suits your property.

Honest comparison of Resi and Mayfair Studio for London home extensions. Mayfair Studio's £1,880 all-in fixed fee vs Resi's £1,500+, what's included, turnaround times, and which suits your project.

Every London borough ranked for home extensions. Real data from 299k Land Registry sales, EPC records, 17 planning constraint datasets, and an 11-region cost model.

London boroughs ranked by planning difficulty using real constraint data. Waltham Forest has 807 Article 4 areas, Richmond 87 conservation areas.

Complete 7-step guide to planning permission for London extensions. Council fee £258, 8-week decision period, timeline table, common refusal reasons, and total cost breakdown.

Planning drawings £1,295–£3,000, building regs £1,500–£4,000, structural engineering £600–£1,500. Cost breakdown by drawing type, factors affecting price, and fixed fee vs hourly comparison.

No legal requirement - but here is the practical case. When professional drawings are essential, what happens when homeowners skip them, and how Mayfair Studio's £1,880 all-in fixed fee covers everything you need.

Fixed-fee architect costs in London 2026. Mayfair Studio's £1,880 all-in fixed fee, what it includes, and how fixed fees compare to hourly (£80–200/hr) and percentage-based (8–15%) charging.

Ranked guide to the best architects for London home extensions. Mayfair Studio's £1,880 all-in fixed fee vs local RIBA practices (8–15%), Resi, and freelance technicians - with comparison table.

Every London borough's Article 4 directions counted from planning.data.gov.uk. Waltham Forest leads with 807, Southwark has 480.

Council-by-council reference for extension policies across England. 296 councils analysed with portal types, SPD coverage, and planning policy URLs.

Kitchen extension costs from DesignForMe survey: 10sqm UK avg £86.5k, London £109k. Build cost, kitchen fit-out, and trade rate breakdown.

EPC energy ratings across London boroughs from DLUHC data. How extensions can improve your rating with Part L 2021 requirements.

How flood risk affects extension planning permission. Flood zone data by London borough, extra costs for flood-resilient construction.

Loft conversion costs from DesignForMe 2025 survey: UK avg £74k, London £88k. Dormer, hip-to-gable, mansard, and Velux costs compared.

How to check if your house is in a conservation area and what it means for your extension. London boroughs ranked by conservation area count.

Average floor area by property type across all 33 London boroughs from EPC data. Why floor area matters for extension potential.

Solid wall homes (pre-1920s) cost 10-20% more to extend. EPC data on wall type distribution and what it means for your extension budget.

Planning application timelines from real data. Statutory 8-week target vs reality. Variation by application type and borough.

How house age affects extension cost. Victorian solid walls add 10-20%, 1930s semis are most straightforward, post-war homes may have asbestos.

Listed buildings counted from planning.data.gov.uk. Westminster leads with 3,455. What listing means for extensions and how to get listed building consent.

EPC data aggregated nationally by property era. Victorian, 1930s, post-war property profiles with floor areas, wall types, energy ratings, and extension potential.

Extension ROI analysis using Land Registry data. 10-20% value uplift is typical. By region: London extensions add the most absolute value.

Daily trade rates for all 11 trades: builder £200-440/day, electrician £250-550, plumber £250-500. London vs Midlands from ConcreteMath 2024/25 data.

Home extensions in Richmond upon Thames 2026: conservation areas in Kew, Twickenham and Ham, Article 4 directions, Green Belt limits, and 2026 costs.

Home extensions in Merton 2026: planning rules, Wimbledon and Mitcham conservation areas, Article 4 directions, and costs for SW19, SW20, CR4, SM4.

Extending in Lewisham 2026: permitted development, Brockley and Blackheath conservation areas, Article 4 directions, planning tips, and 2026 costs inc VAT.

Home extensions in Haringey 2026: planning rules, conservation areas in Crouch End, Muswell Hill and Highgate, Article 4 directions, and 2026 costs.

Extending in Ealing 2026: SPD 4 design rules, Brentham Garden Estate Article 4 direction, conservation areas, planning tips, and typical 2026 costs inc VAT.

Guide to home extensions in Brent 2026. Covers the new January 2025 SPD, conservation areas, Article 4 directions, Mapesbury Estate rules, and typical costs.

Solar panels on extensions London 2026: Part 14 Class A planning rules, costs from £1,400/kWp, SEG payments, battery storage, and typical payback periods.

CDM Regulations 2015 for London home extensions: when they apply, domestic client duties, duty holders, HSE F10 notification, and the Health and Safety file.

Around 30% of householder planning applications in London are refused. Here are the 10 most common reasons - and how to avoid each one before you submit.

Building control for London extensions 2026: full plans vs building notice, inspection stages, completion certificates, LABC vs approved inspectors, and fees.

Home extension insurance London: notify your insurer, arrange site cover, and get a structural warranty. What each policy covers and when you need it.

Does a home extension raise council tax in London? Usually not while you live there - here is what triggers a VOA reassessment and how to respond if it does.

Granny annexe London 2026: planning rules, garage conversion £25k–£50k, extension annexe £60k–£120k inc VAT, CIL exemption, and council tax discount explained.

Modular extensions London 2026: SIPs, timber frame, steel frame and volumetric pods. Costs vs traditional build, planning rules, building regs, and mortgages.

Dormer extension London 2026: flat roof, shed, hip-to-gable and L-shaped dormers. Costs, Class B permitted development rules, and party wall guidance.

1930s semi extension London 2026: rear £55k–£120k, side £45k–£85k, hip-to-gable £55k–£90k, wrap-around £80k–£150k inc VAT. Planning and structure guide.

London extension premium quantified: kitchen extensions cost 2.06x non-London, rear extensions 1.94x. Regional multipliers from Inner London 1.25 to North East 0.90.

UK property price trends from 31M Land Registry transactions. London vs rest of England premium, price by property type, and what it means for extensions.

Extending in Barnet in 2026? Covers permitted development, Hampstead Garden Suburb restrictions, conservation areas, Article 4 directions, and typical costs.

Heat pump during a London extension 2026: costs inc VAT, the £7,500 Boiler Upgrade Scheme grant, underfloor heating, running cost vs gas, and planning rules.

Future Homes Standard and London extensions 2026: Part L U-values (walls 0.18, roof 0.15), heat pumps, triple glazing, MVHR, solar PV, and 0% VAT on upgrades.

45-degree rule for London extensions: how it is measured, which boroughs apply it, and what to do if your design fails the test. 25-degree rule also covered.

The 4-year rule is replaced by a 10-year enforcement period from April 2024. What this means for London homeowners, mortgages, and certificates of lawful use.

Lawful development certificate London: £206 application fee, £700–£2,000 all-in. When you need CLOPUD vs CLEUD and how to build a strong 8-week case.

PD changes 2026: larger rear extensions without planning permission, simplified loft conversion rules, curtilage changes. What London homeowners should do now.

Kitchen extension costs London 2026: small 15m² from £60k, medium 20m² from £85k, large 30m² from £120k inc VAT. Build cost vs kitchen fit-out by spec level.

London extension costs by size 2026: 3m×6m is £72k–£110k, 4m×6m is £98k–£142k, all inc VAT. Covers architect, engineer, building regs and contingency.

Garden room vs extension London 2026: garden rooms £15k–£40k, extensions £50k–£120k+. Planning rules, value added, build time, and which option suits your plot.

3m kitchen extension London 2026: costs £50k–£108k inc VAT depending on width. No planning application under permitted development. Layouts and design tips.

Extension above a garage London 2026: integral £25k–£45k, new storey above integral £55k–£90k, above detached £65k–£110k inc VAT. Planning and structure guide.

Add a storey to your London home 2026: Class AA and AB permitted development, prior approval, costs £120k–£200k+ inc VAT, and structural challenges.

Flat extension London 2026: costs £55k–£130k inc VAT. No permitted development for flats - planning permission always required. Leasehold consent explained.

Mansard loft conversion London 2026: basic £65k–£95k, mid-range £90k–£130k, high-spec £130k–£180k inc VAT. Planning, party wall, and space vs rear dormer.

Detached house extension London 2026: rear £82k–£118k, two-storey £140k–£220k, wrap-around £110k–£170k inc VAT. 8m PD rules and design guide.

Victorian house extension costs London 2026: side return £40k–£75k, rear £55k–£120k, wrap-around £80k–£150k, loft £55k–£120k. Conservation areas covered.

17 constraint datasets analysed from planning.data.gov.uk. Conservation areas, listed buildings, Article 4 directions, TPOs, flood zones ranked by LPA.

Extension costs across 11 regions from real data. Regional multipliers, DesignForMe survey data from 1,500+ projects, and trade rates by region.

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.

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.

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.

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.

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.

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.

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.

Complete guide to two storey extensions in London 2026. Costs £72k-£220k inc VAT. Planning permission almost always required. Cheaper per m² than single storey. 14-20 months from start to finish.

London architect fees 2026: 8–15% of build cost or £3k–£15k fixed. RIBA stage breakdown, what drives pricing, red flags to avoid, and how to compare quotes.

Extending in Kensington & Chelsea (RBKC)? 73% conservation coverage, strict basement rules, costs 20–30% above London average. Expert planning and design guide.

Underfloor heating for London extensions 2026: wet vs electric UFH from £25/m², Part L building regs compliance, best flooring choices, and installation advice.

How to match London stock bricks for extensions. New vs reclaimed, mortar matching, conservation area requirements, and sourcing guide. Updated 2026.

Six proven kitchen-diner extension layouts for London homes. Galley, L-shaped, island, linear, U-shaped, and broken-plan designs with costs and minimum sizes.

Skylights from £500 or roof lanterns from £2,500? Compare light performance, thermal efficiency, planning rules, and design impact for your London extension.

Bifold doors £3k-8k vs sliding doors £4k-12k for extensions. Bifolds open 90%+, sliding offer slim sightlines and better thermals. Full London comparison guide.

Right to light can stop your extension even with planning permission. 45-degree rule explained, BRE daylight assessment from £800, how to resolve neighbour disputes.

Building within 3m of a public sewer? Thames Water build over approval takes 6–12 weeks and costs £300–£1,000. Step-by-step guide for London extension owners.

Complete guide to porch extensions in London. Costs from £2,000, permitted development rules, design options for Victorian and modern homes. Updated 2026.

Complete guide to home extensions in Lambeth. Planning rules, basement SPD, conservation areas, design guidance, and typical costs. Updated 2026.

Complete guide to prior approval in London. Larger home extensions, office to residential conversions, and other developments that need council notification.

Complete guide to building regs for extensions. Structural, fire safety, insulation, ventilation requirements. Costs and inspection stages.

Everything you need to know about building without planning permission in London. Borough-specific rules, Article 4 directions, and instant permitted development checker.

Wandsworth extension guide 2026: permitted development rules, basement policy, conservation areas, and typical costs for rear and side return extensions.

Complete guide to home extensions in Hackney. New SPD guidance, planning permission, conservation areas, basement policy, and typical costs. Updated 2026.

Camden extension guide 2026: planning rules, permitted development, Article 4 directions, conservation areas, basement policy, and costs. Updated Feb 2026.

Builder shortages, rising material costs, planning delays and Part L changes - the key challenges facing London homeowners extending their properties in 2026.

Will your extension pay for itself? Complete ROI analysis for London extensions. Find out which projects add 15-25% value vs which lose money.

Finance a London extension in 2026: remortgage, further advance, or home improvement loan compared. Options for £50k–£150k projects with staged payments.

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.

48 conservation areas in Southwark. Side return £80k-120k, rear £70k-105k. Dulwich, Peckham, Camberwell planning. Victorian terraced costs.

Maritime Greenwich World Heritage Site restrictions. 20 conservation areas. Side return £55k-90k, rear £65k-95k. Victorian/Edwardian terraced costs.

40/42 conservation areas restrict permitted development. Side return £50k-110k, rear £60k-90k. Article 4 directions extensive. Typical terraced house extension costs.

Wandsworth extension guide 2025: permitted development rules, basement policy, conservation areas, and typical costs for rear and side return extensions.

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 £52k vs pitched £60k for 30m² extension. Flat: cheaper, easier permitted development, 20-year lifespan. Pitched: 50-90 years, less maintenance, better resale.

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 solutions: 3-6m depth options, vertical design, minimal garden loss. 10-15m² extensions £35k-£60k.

Orangery vs extension comparison. Orangeries £30k-£80k (more light, £500-1000/m² cheaper), extensions £50k-£120k (better insulation). Planning permission, costs, ROI.

Wrap-around extensions combine side return + rear extension for maximum space. £75k-145k cost, planning permission needed, ideal for terraced houses.

£50k kitchen vs £75k extension ROI analysis. Kitchen adds 5-10%, extension adds 10-15%. Combined strategies and decision framework.

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.

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.

How to finance your London extension. Remortgage vs loans, further advance, staged payments. Compare costs for £50k-150k projects.

Actual extension costs from 5,000+ London projects. Ground floor, loft, side return costs by borough with free calculator.

Everything about side return extensions in London. Average costs £55k-85k, planning vs permitted development, kitchen integration, and real examples.

Extension options for London terraced houses. permitted development limits, party walls, side returns, wrap-around extensions, and cost breakdowns.

Building in conservation areas. Restricted permitted development rights, planning requirements, materials, costs, and getting approval in 600+ London areas.

Extension options for semi-detached houses. permitted development limits, rear and side extensions, loft conversions, costs, and one-side party walls.

Kitchen extension guide. Open-plan layouts, bi-fold doors, lighting, costs £75k-120k. Rear, side return, and wrap-around options.

Complete extension timeline from design to completion. 6-12 months typical. Planning, building regs, party wall, construction stages.

Honest comparison of traditional architects vs online services like Mayfair Studio. Costs, design quality, when to use each approach.

Complete guide to home extensions in Lambeth. Planning rules, basement SPD, conservation areas, design guidance, and typical costs. Updated 2025.

Complete guide to home extensions in Hackney. New SPD guidance, planning permission, conservation areas, basement policy, and typical costs. Updated 2025.

Camden extension guide 2025: planning rules, permitted development, Article 4 directions, conservation areas, basement policy, and costs. Updated Oct 2025.

Extending a listed building in London needs listed building consent. Grade I and II rules, conservation officer advice, and realistic costs explained.

Building regulations for home extensions: structural, fire, insulation and drainage rules explained. Approval costs £1,000–£2,000 with full inspection stages.

Permitted development rights London 2025: size limits by type, Article 4 directions by borough, what you can build without planning permission. Oct 2025.

Should you extend or move house in London? Complete cost comparison including stamp duty 2025 changes, extension costs, moving costs, and ROI analysis.

Rear extension London guide 2025: single-storey costs £75k–£120k, two-storey £110k–£150k. Permitted development limits, planning rules, and design options.

London loft conversion guide 2025: dormer, mansard, hip-to-gable costs £45k–£85k. Building regulations, planning rules, and common mistakes to avoid.

Navigate the biggest obstacles facing London homeowners in 2025. Labour shortages, material costs up 12%, planning delays, and new building regulations explained.

Ranked list of London traffic consultants for home extensions. Transport statements, parking surveys, Construction Management Plans from £350.

Ranked list of London drainage consultants for home extensions. Thames Water Build Over agreements, CCTV surveys from £250, soakaway design specialists.

Ranked list of London arboriculturists and ecologists for home extensions. BS5837 surveys from £350. Essential for TPO trees, bat surveys, and planning compliance.

Data analysis of Newham planning refusals reveals 10 most common rejection reasons. Olympic regeneration zones, Victorian terraces. 92% prior approval success rate.

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.

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.

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.

Data analysis of Croydon planning refusals reveals 10 most common rejection reasons. Suburban character issues account for 38%. Expert tips to avoid refusal.

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.

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.

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.

Build a sustainable extension in London. Part L 2021 requirements, EPC improvements, heat pumps, insulation standards, and how to reduce running costs.

Complete guide to finding and vetting builders in London. Get quotes, check references, understand contracts, and avoid cowboys. Protect your extension project.

Complete guide to prior approval in London. Larger home extensions, office to residential conversions, and other developments that need council notification.

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.

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.

Complete guide to lighting your extension. Natural light strategies, LED layouts, Part L requirements, and how to create the perfect atmosphere.

Complete guide to open plan kitchen extensions in London. Layout options, zoning strategies, structural considerations, and design tips for modern living.

Complete checklist for your London extension project. From initial ideas through to completion, every step you need to follow for a successful build.