⭐ 9.96/10 Checkatrade · 114+ Reviews
📞 07359 872594
Cost Guides5 min read

Kitchen Extension Costs in London Victorian Terraces: Full Budget Breakdown 2025-2026

A kitchen extension on a London Victorian terrace is one of the most transformative and most expensive single projects a homeowner can undertake. Combining a structural rear extension with a new kitchen installation, and often adding glazing, drainage, electrical, and M&E work as part of the same project, the total cost of a kitchen extension on a London Victorian terrace in 2025-2026 ranges from approximately £45,000 for a modest 3m × 3m single-storey extension with a mid-range kitchen, to £120,000+ for a large open-plan rear extension with premium glazing and a high-specification kitchen. This guide provides a detailed cost breakdown of each component.

Key Takeaways

  • ✓Total cost of a kitchen extension on a London Victorian terrace: small (9m²) £45,000-70,000; medium (15m²) £70,000-100,000; large (25m²) £100,000-150,000+ — all inclusive of structure, glazing, kitchen, M&E, and professional fees
  • ✓The kitchen itself is the biggest discretionary variable — budget kitchen supply £3,000-8,000; mid-range £8,000-20,000; bespoke high-end £25,000-80,000+
  • ✓Glazing (roof lantern + bifolding doors) adds £6,000-18,000 to the project cost but is often the most visible quality differentiator in an open-plan kitchen extension
  • ✓Single-storey rear extensions up to 3m deep may be permitted development (terraced house) — up to 6m under prior approval; conservation areas almost always require a planning application
  • ✓London Clay foundations must be at minimum 1.2m depth — and 1.5-2.0m+ where trees are adjacent (shrinkable clay heave risk); structural engineer sign-off is mandatory
  • ✓Project timeline: typically 16-24 weeks from design start to completion for a medium kitchen extension on a London Victorian terrace

Contents

  1. 1. Extension Structure, Glazing, and M&E Costs
  2. 2. Kitchen Supply, Fit, and Total Budget
  3. 3. Frequently Asked Questions

Extension Structure, Glazing, and M&E Costs

COMPONENT 1: THE STRUCTURAL EXTENSION — WALLS, ROOF, AND FOUNDATION: THE STRUCTURAL COST OF A SINGLE-STOREY REAR EXTENSION ON A LONDON VICTORIAN TERRACE IS DRIVEN BY: - EXTENSION SIZE: TYPICAL LONDON VICTORIAN TERRACE REAR EXTENSIONS ARE 3M DEEP × THE FULL WIDTH OF THE HOUSE (APPROXIMATELY 4-5M) = 12-18M² OF NEW FLOOR AREA. PERMITTED DEVELOPMENT ALLOWS UP TO 6M DEEP (SINGLE-STOREY, TERRACED HOUSE) UNDER THE PRIOR APPROVAL ROUTE. - STRUCTURAL WALLS (BRICK AND BLOCK): THE REAR EXTENSION SIDE WALLS AND REAR WALL ARE TYPICALLY CAVITY CONSTRUCTION (102MM BRICK OUTER LEAF + CAVITY + 100MM BLOCKWORK INNER LEAF WITH PARTIAL FILL CAVITY INSULATION) — COST APPROXIMATELY £150-250/M² OF WALL. - FLAT ROOF (THE MOST COMMON ROOF FORM FOR SINGLE-STOREY LONDON EXTENSIONS): STRUCTURAL FLAT ROOF (TIMBER OR STEEL CASSETTE + WARM ROOF INSULATION + EPDM OR GRP MEMBRANE) — COST APPROXIMATELY £100-180/M² OF ROOF AREA. - FOUNDATIONS: CONCRETE STRIP FOUNDATION AT MINIMUM 1.2M DEPTH (LONDON CLAY SHRINKABLE CLAY REQUIREMENT — NHBC CHAPTER 4.2) OR 1.5-2.0M+ DEPTH WHERE LARGE TREES ARE ADJACENT (THE TREE DISTANCE RULE — REFER TO NHBC TABLE 4.2-2 FOR MINIMUM FOUNDATION DEPTH BY TREE SPECIES AND DISTANCE). COST: £150-300/M LINEAR RUN OF FOUNDATION (SUPPLY AND POUR). - STRUCTURAL OPENING (REMOVING THE EXISTING REAR WALL AND INSERTING A STEEL RSJ OR COMPOUND BEAM): THE STEEL BEAM SPANNING THE NEW OPENING (TYPICALLY 3-5M CLEAR SPAN FOR A FULL-WIDTH OPENING) COSTS £500-2,500 FOR THE STEEL SUPPLY, PLUS £1,500-4,000 FOR THE STRUCTURAL OPENING WORKS (TEMPORARY SUPPORT, MASONRY, LINTEL BUILD-IN, AND DECORATION). STRUCTURAL ENGINEER DESIGN AND CALCULATIONS: £500-1,500.

COMPONENT 2: GLAZING (ROOF LANTERN, ROOFLIGHT, OR BIFOLD/SLIDING DOORS): - ROOF LANTERN (FIXED GLAZED PYRAMID ABOVE THE FLAT EXTENSION ROOF — ALUMINIUM FRAME): A 2M × 1.5M ROOF LANTERN SUPPLY AND FIT: £3,000-8,000 (DOUBLE GLAZED, POWDER-COATED ALUMINIUM, LOW-E GLASS). A LARGE 3M × 2M ROOF LANTERN: £5,000-15,000. - FLAT ROOF ROOFLIGHT (FIXED, FLUSH OR UPSTAND — DOUBLE OR TRIPLE GLAZED, 1200×1200MM): £1,500-3,500 SUPPLY AND FIT. - BIFOLD DOORS OR SLIDING DOORS (ALUMINIUM — REAR OPENING OF THE KITCHEN EXTENSION): A 3M WIDE ALUMINIUM BIFOLD DOOR (3-PANEL) SUPPLY AND FIT: £3,000-6,000 (DOUBLE GLAZED, POWDER-COATED ALUMINIUM FRAME). A 4M WIDE BIFOLDING DOOR SET: £4,000-10,000. ALUMINIUM SLIDING DOORS (2-3 PANELS, 3M WIDE): £3,500-8,000. - TOTAL GLAZING PACKAGE FOR A TYPICAL LONDON VICTORIAN TERRACE KITCHEN EXTENSION (ROOF LANTERN + BIFOLDING DOORS): £6,000-18,000.

COMPONENT 3: FIRST-FIX M&E (PLUMBING, HEATING, ELECTRICS): - DRAINAGE: RELOCATION OF THE KITCHEN SINK AND DISHWASHER DRAINAGE INTO THE EXTENSION (NEW 40MM WASTE RUNS TO THE EXISTING YARD GULLY OR A NEW GULLY IN THE EXTENSION FLOOR): £500-1,500. - GAS: EXTENSION OF THE GAS SUPPLY TO THE NEW KITCHEN ISLAND HOB POSITION (OR INSTALLATION OF AN INDUCTION HOB WITH ELECTRICAL SUPPLY INSTEAD): £300-800 FOR GAS; £200-500 FOR INDUCTION SUPPLY CABLE ONLY. - ELECTRICAL (FIRST FIX): KITCHEN EXTENSION ELECTRICAL FIRST FIX (SOCKETS, RING MAIN, LIGHTING CIRCUIT, EXTRACTION FAN CIRCUIT, UNDERFLOOR HEATING): £1,500-3,500. - UNDERFLOOR HEATING: ELECTRIC UFH UNDER THE EXTENSION FLOOR TILES (APPROX 12-18M² AT £30-60/M² SUPPLY ONLY; FITTING AND THERMOSTAT: £300-800): TOTAL £800-2,000. HYDRONIC UFH (CONNECTED TO EXISTING BOILER): £2,500-5,000 FOR THE EXTENSION. - TOTAL FIRST-FIX M&E: £2,500-8,500.

Kitchen Supply, Fit, and Total Budget

COMPONENT 4: KITCHEN SUPPLY (UNITS, WORKTOP, APPLIANCES): THE KITCHEN ITSELF IS A MAJOR COST DRIVER IN THE TOTAL PROJECT: - BUDGET KITCHEN (HOWDENS GLENDEVON, WREN BOSTON, MAGNET BASE AND WALL UNITS + LAMINATE WORKTOP): £3,000-8,000 SUPPLY ONLY (10-15 BASE AND WALL UNITS + WORKTOP + SINK). - MID-RANGE KITCHEN (HOWDENS PEMBROKE OAK, WREN CAMBRIDGE, NOBILIA STEP, IKEA SEKTION — 10-18 UNITS + SOLID QUARTZ OR GRANITE WORKTOP — SILESTONE, CAESARSTONE, QUARTZ MASTER): £8,000-20,000 SUPPLY ONLY. - HIGH-END KITCHEN (TOM HOWLEY, DEVOL, JOHN LEWIS OF HUNGERFORD, SMALLBONE, BULTHAUP — BESPOKE PAINTED UNITS, STONE WORKTOPS, INTEGRATED MIELE/SIEMENS/GAGGENAU APPLIANCES): £25,000-80,000+ SUPPLY ONLY. - INTEGRATED APPLIANCES (DISHWASHER, FRIDGE-FREEZER, OVEN, HOB, EXTRACTION): MID-RANGE INTEGRATED APPLIANCES — £3,000-8,000 SUPPLY ONLY (AEG, BOSCH, NEFF); HIGH-END (MIELE, GAGGENAU): £8,000-25,000+.

COMPONENT 5: KITCHEN FIT AND SECOND-FIX: - KITCHEN FITTING (UNITS, WORKTOP, APPLIANCES, PLUMBING AND ELECTRICAL CONNECTIONS — LABOUR ONLY): £1,500-4,000 FOR A TYPICAL VICTORIAN TERRACE KITCHEN EXTENSION (DOES NOT INCLUDE FIRST-FIX PLUMBING OR ELECTRICS).

COMPONENT 6: INTERNAL FINISHES (FLOOR, CEILING, DECORATION): - FLOOR (LARGE-FORMAT PORCELAIN TILE — 600×600MM OR 600×1200MM — SUPPLY AND FIT): £60-120/M² (MID-RANGE PORCELAIN); £100-200/M² (PREMIUM); FOR 12-18M² = £720-3,600. - CEILING (PLASTERBOARD, SKIM, AND PAINT OR EXPOSED CONCRETE/TIMBER): £15-35/M² (PLASTERBOARD AND SKIM); ADD PAINT. - PAINTING AND DECORATION: £1,000-3,000 FOR THE EXTENSION.

TOTAL BUDGET SUMMARY — LONDON VICTORIAN TERRACE KITCHEN EXTENSION (2025-2026): - SMALL (3M × 3M = 9M², BUDGET KITCHEN, BASIC GLAZING): £45,000-70,000 - MEDIUM (3.5M × 4.5M = 15M², MID-RANGE KITCHEN, ROOF LANTERN + BIFOLDS): £70,000-100,000 - LARGE (4.5M × 5.5M = 25M², HIGH-SPEC KITCHEN, PREMIUM GLAZING): £100,000-150,000+

PROFESSIONAL FEES: - ARCHITECT OR DESIGNER (PLANNING DRAWINGS, WORKING DRAWINGS): £2,000-6,000 - STRUCTURAL ENGINEER (BEAM DESIGN, FOUNDATION SPEC): £500-1,500 - PLANNING APPLICATION FEE (IF NOT PERMITTED DEVELOPMENT): £206 (HOUSEHOLDER APPLICATION 2025) - PARTY WALL SURVEYOR (IF WITHIN 3M OF A NEIGHBOUR\'S FOUNDATION): £750-2,500 PER NEIGHBOUR

Frequently Asked Questions

How much does a kitchen extension cost in London in 2025?▼
A SMALL SINGLE-STOREY REAR EXTENSION (3M × 3M = 9M²) WITH A BUDGET KITCHEN AND BASIC GLAZING: £45,000-70,000 ALL-IN. A MEDIUM EXTENSION (3.5M × 4.5M = 15M²) WITH A MID-RANGE KITCHEN AND ROOF LANTERN + BIFOLDING DOORS: £70,000-100,000. A LARGE OPEN-PLAN EXTENSION (4.5M × 5.5M = 25M²) WITH A PREMIUM KITCHEN AND HIGH-SPEC GLAZING: £100,000-150,000+. ALL COSTS INCLUDE STRUCTURE, GLAZING, M&E, KITCHEN SUPPLY AND FIT, FINISHES, AND PROFESSIONAL FEES.
What is the biggest cost in a kitchen extension in a London Victorian terrace?▼
FOR A TYPICAL LONDON VICTORIAN TERRACE KITCHEN EXTENSION, THE COSTS ARE ROUGHLY: STRUCTURE (WALLS, ROOF, FOUNDATIONS): 30-40% OF TOTAL; GLAZING (ROOF LANTERN + BIFOLDS): 10-20%; KITCHEN SUPPLY: 20-35%; FIRST-FIX M&E: 8-15%; FINISHES: 5-10%; PROFESSIONAL FEES: 3-8%. THE KITCHEN ITSELF IS OFTEN THE SINGLE LARGEST DISCRETIONARY COST — A BUDGET KITCHEN (£3,000-8,000 SUPPLY ONLY) VS A HIGH-END BESPOKE KITCHEN (£25,000-80,000+ SUPPLY ONLY) CHANGES THE PROJECT TOTAL DRAMATICALLY.
Do I need planning permission for a kitchen extension in London?▼
SINGLE-STOREY REAR EXTENSIONS OF UP TO 3M DEPTH (TERRACED HOUSE, LONDON — WITHIN THE ARTICLE 4 DIRECTION EXEMPTIONS) MAY BE PERMITTED DEVELOPMENT (NO PLANNING APPLICATION REQUIRED). EXTENSIONS UP TO 6M DEPTH MAY QUALIFY UNDER THE PRIOR APPROVAL ROUTE (NEIGHBOUR CONSULTATION SCHEME — A 42-DAY CONSULTATION PROCESS). EXTENSIONS BEYOND THESE LIMITS, OR IN CONSERVATION AREAS, OR ON LISTED BUILDINGS REQUIRE A FULL PLANNING APPLICATION (HOUSEHOLDER APPLICATION — £206 FEE IN 2025). ALWAYS CHECK WITH THE LOCAL PLANNING AUTHORITY BEFORE STARTING DESIGN WORK.
How long does a kitchen extension take in a London Victorian terrace?▼
A TYPICAL SINGLE-STOREY REAR KITCHEN EXTENSION ON A LONDON VICTORIAN TERRACE (15M², MEDIUM SPECIFICATION): APPROXIMATELY 16-24 WEEKS FROM DESIGN START TO COMPLETION. BREAKDOWN: DESIGN AND PLANNING (4-8 WEEKS); STRUCTURAL ENGINEER AND BUILDING REGS (4-6 WEEKS); TENDERING AND PROCUREMENT (2-4 WEEKS); SITE WORKS (8-14 WEEKS). LARGER OR MORE COMPLEX PROJECTS (BASEMENT EXTENSIONS, HERITAGE PROPERTIES, DIFFICULT SITE ACCESS) TAKE LONGER.
Can I add a kitchen extension to a Victorian terrace in a conservation area?▼
YES — BUT PLANNING PERMISSION WILL ALMOST CERTAINLY BE REQUIRED. IN A CONSERVATION AREA, THE DESIGN MUST BE SENSITIVE TO THE PERIOD CHARACTER OF THE TERRACE — CONSERVATION OFFICERS OFTEN ACCEPT CONTEMPORARY (GLAZED, FLAT-ROOFED) REAR EXTENSIONS AS THESE ARE CLEARLY OF THEIR TIME AND DO NOT MIMIC THE ORIGINAL ARCHITECTURE. HOWEVER, THE USE OF PERMITTED DEVELOPMENT RIGHTS IS RESTRICTED OR REMOVED IN SOME CONSERVATION AREAS WITH ARTICLE 4 DIRECTIONS. CONSULT THE LOCAL PLANNING AUTHORITY BEFORE DESIGN STARTS.

Important Note

This guide is for general information only. Building regulations, planning rules, and legal requirements change regularly and vary by local authority. Always seek professional advice specific to your project and location. RCB Design & Build offers free initial consultations — book your free survey.

Ready to Discuss Your Project?

Free site survey. No obligation. Covering all Greater London & M25.

Book a Project ReviewCall 07359 872594

Related Guides

Cost Guides · 5 min read

Bathroom Renovation Costs in London Victorian Terraces: What to Budget in 2025-2026

Read →
Structural Works · 3 min read

Structural Opening Creation in London Victorian Terraces: Steels, Props, and Building Control

Read →
Windows, Doors & Glazing · 9 min read

Bifold Doors for London Victorian Homes: Origin, Aluk, Smart, Schüco, Specification, and Build Guide

Read →
← Back to all guides
📞 Call now💬 WhatsAppFree Quote