Wrap-Around Extension London: Complete Guide to L-Shaped Extensions
Wrap-around extensions combine side return and rear extensions to maximize ground floor space. Perfect for Victorian terraces. £75k-145k cost, nearly always needs planning permission, adds 15-20% property value.
Quick Summary
- Cost: £75,000-£145,000 (45m² typical size)
- Planning: Nearly always requires full planning permission (not PD)
- Timeline: 5-7 months (3-4 months planning + 12-16 weeks build)
- ROI: Adds 15-20% property value (£100k-180k on £650k-900k homes)
- Best for: Victorian/Edwardian terraced houses with side return access
What Is a Wrap-Around Extension?
A wrap-around extension (also called an L-shaped extension) combines a side return extension with a rear extension to create one continuous space that wraps around the side and back of your property. According to Homebuilding & Renovating, they're particularly popular for Victorian and Edwardian terraced houses where the side return (narrow alleyway beside the kitchen) can be incorporated into the living space.
Typical Wrap-Around Configuration
Side Return Component:
- •1.2-2.5m wide (typical side return width)
- •4-6m long (from front to back boundary)
- •Adds 6-15m² floor area
Rear Extension Component:
- •Full width of property (4-5m typical)
- •3-6m deep projection
- •Adds 15-30m² floor area
Total: 25-45m² of new living space, creating large open-plan kitchen-dining-living area.
Key advantage: Wrap-arounds maximize ground floor space while preserving garden length. You gain significant floor area from otherwise-wasted side return, plus moderate rear extension that doesn't consume entire garden. Result: 40-50m² kitchen-diner vs 10-15m² cramped galley kitchen in typical Victorian terrace.
Wrap-Around Extension Costs London 2025
According to PriceYourJob UK, wrap-around extensions cost £75,000-£145,000 for typical 45m² size in London. Costs vary by specification level:
| Specification | Cost per m² | 35m² Extension | 45m² Extension | What You Get |
|---|---|---|---|---|
| Budget | £2,100-£2,400 | £73k-£84k | £95k-£108k | IKEA/Howdens kitchen, standard glazing, vinyl flooring, basic finishes |
| Mid-Range | £2,500-£2,900 | £88k-£102k | £113k-£131k | Magnet/Howdens quality kitchen, bi-fold doors, underfloor heating, quartz worktops |
| High-End | £3,000-£3,500 | £105k-£123k | £135k-£158k | German kitchen, Crittall-style doors, premium glazing, designer finishes |
Total Project Budget Breakdown (45m² Extension)
Construction Cost
65-70% of total budget
Builder costs for structure, foundations, roofing, glazing, plastering, electrics, plumbing, decoration. Does NOT include kitchen or professional fees.
Kitchen & Finishes
15-20% of total budget
Kitchen units, worktops, appliances, flooring throughout extension. £18k minimum for Howdens-quality, £35k+ for German kitchens.
Professional Fees
8-12% of total budget
- •Architect/designer: £4k-£8k (plans + planning application)
- •Structural engineer: £1.5k-£3k
- •Party wall surveyor: £1k-£3k (both sides if needed)
- •Planning application fee: £258
- •Building control: £1.5k-£2.5k
Contingency
5-10% of total budget
Unexpected issues: asbestos removal, drainage rerouting, structural surprises, material price increases, design changes during construction.
Total realistic budget: £130k-£185k for mid-range 45m² wrap-around extension including all costs. Budget £2,900-£4,100/m² all-in for realistic planning. Many quotes only show construction cost (£2,100-£3,000/m²) excluding kitchen, fees, contingency - this causes budget blowouts.
Planning Permission for Wrap-Around Extensions
According to CK Architectural, wrap-around extensions almost always require full planning permission rather than permitted development rights. Here's why:
Why Wrap-Arounds Can't Use Permitted Development
- Width restriction: Side extensions under PD must not exceed half the width of original house. Full-width wrap-arounds exceed this limit.
- Corner issue: The corner where side and rear meet doesn't share a wall with original property, creating PD qualification problems.
- Multiple extensions: PD rules apply separately to side and rear extensions. Combining them creates complexities that exceed PD limits.
- Size: 40-45m² total area often exceeds cumulative PD allowances for side + rear extensions combined.
Potential Future Changes (2025-2026)
UK government consulted on changes to permitted development rights in 2024 that would allow wrap-around single storey extensions under PD. However, as of January 2025, these changes are NOT yet law. Always assume you need planning permission until confirmed otherwise by architect or planning consultant.
Smaller "partial wrap-arounds" (side return + modest 2-3m rear extension) may qualify under current PD rules if they meet all individual side and rear extension criteria. Your architect can assess this.
Planning Application Process & Timeline
Pre-application advice (optional)
2-4 weeks, £150-£300. Submit sketch proposals to council for informal feedback before full application.
Prepare plans & submit application
4-8 weeks for architect to prepare detailed drawings, design & access statement, submit application. Fee: £258 + architect costs.
Neighbour consultation
21 days statutory consultation. Neighbors can submit objections. Terraced houses: expect concerns about light loss, overlooking.
Council decision
8-13 weeks from validation. May request revisions. Most wrap-arounds approved if designed sensitively (matching materials, respectful of neighbor amenity).
Total planning timeline: 3-5 months from hiring architect to approval. Factor this into project schedule.
Design Considerations for Wrap-Around Extensions
1. Glazing Strategy: Maximizing Natural Light
Wrap-arounds offer multiple glazing opportunities that single extensions don't. The side return provides a second light source, creating bright corner spaces.
Best Glazing Options:
- • Full-width bi-fold/sliding doors on rear (4-5m wide)
- • Large fixed glazing on side return facing garden
- • Roof lights above side return (if narrow)
- • Corner glass detail where side meets rear
Avoid:
- • Windows on side boundary wall (overlooking issues)
- • Cheap roof lights (condensation, leaks)
- • Minimal glazing in side return (feels dark tunnel)
- • Standard windows instead of full-height glazing
2. Layout Planning: Kitchen Placement
Two main approaches for kitchen layout in wrap-around extensions:
Option A: Kitchen in side return + dining in rear
Galley kitchen along side return (1.2-2.5m wide), dining/living in wider rear extension. Works well for narrow side returns.
Pro: Efficient use of narrow space. Con: Kitchen feels separate from dining, less sociable.
Option B: Kitchen in rear corner + dining throughout (Recommended)
Island/L-shaped kitchen in rear extension corner, dining table in center, seating area in side return section. Creates true open-plan feel.
Pro: Sociable, modern open-plan. Con: Requires wider side return (1.8m+ minimum) to work well.
3. Ceiling Height: Creating Volume
Standard extensions: 2.4m ceiling height (matches existing house). Better approach for wrap-arounds: vary ceiling heights to create drama and define zones.
- •Main space (rear): 3.0-3.5m ceiling with large roof lights or vaulted ceiling
- •Side return: 2.6-2.8m (lower ceiling acceptable if narrow)
- •Connection to existing house: Match existing ceiling (2.4m) for seamless flow
Cost impact: Raising ceiling from 2.4m to 3.0m adds £3k-6k (taller walls, more glazing) but transforms the space. Worth it on 40m²+ extensions.
4. Materials & Finishes: Matching vs Contemporary
Planning officers prefer materials that respect the character of original Victorian/Edwardian house. Two successful approaches:
Traditional Approach:
- • Matching brickwork
- • Slate or tile roof to match existing
- • Painted timber bi-fold doors
- • Traditional proportions
Easier planning approval, blends seamlessly
Contemporary Approach:
- • Render or contrasting brick
- • Flat roof with parapet detail
- • Aluminium/Crittall-style glazing
- • Modern clean lines
More expensive, may face planning scrutiny
When Wrap-Around Extension Makes Sense
Choose Wrap-Around If:
- You have a side return (even narrow 1.2m+ works) that's currently wasted space
- Budget is £120k-£180k (enough for quality wrap-around including kitchen)
- You want maximum ground floor space without losing entire garden
- Property value is £600k+ (ROI improves significantly above this threshold)
- You're staying 7-10+ years (justifies planning permission effort and disruption)
- Neighbors are reasonable (planning more likely to succeed)
Don't Do Wrap-Around If:
- Budget under £100k (won't get quality wrap-around + kitchen for less)
- No side return access (can't do wrap-around without side component)
- Selling within 3-5 years (planning timeline + disruption not worth it for short stay)
- Conservation area with strict planning constraints (approval unlikely)
- Property value under £450k (ROI will be 70-85%, financially marginal)
- Difficult neighbors who will object (planning may be rejected or heavily compromised)
Alternative to consider: If you can't do full wrap-around (budget, planning, or access reasons), consider "side return only" extension (£55k-85k, often qualifies under PD if under half width). Delivers 50-60% of the space gain for 60% of the cost. Or do side return now, rear extension later when budget allows.
Frequently Asked Questions
Can I do a wrap-around extension under permitted development?
Almost certainly no. Wrap-around extensions exceed the width restrictions for side extensions under PD (can't be more than half the width of original house), and the corner where side meets rear creates qualification issues. UK government consulted on allowing wrap-arounds under PD in 2024, but as of January 2025, this is not yet law. Small "partial wrap-arounds" (narrow side return + modest 2m rear) may qualify if they meet all individual PD criteria - your architect can assess.
What's the minimum side return width for a wrap-around?
Technically 1.2m minimum (enough for galley kitchen along side), but 1.8m+ is far better. Under 1.5m feels narrow and limits layout options - you can only really do galley kitchen in the side portion. 2.0m+ is ideal: enough for kitchen island that straddles the side-rear junction, creating true open-plan feel. If your side return is under 1.2m, consider rear extension only instead.
How much value does a wrap-around extension add?
15-20% property value increase on Victorian terraced houses worth £600k-£900k. On £700k property, expect £105k-£140k value increase from £130k wrap-around (80-108% ROI). Higher value properties (£800k+) see better ROI (90-115%) because same extension cost represents smaller % of property value. Lower value properties (£450k-£550k) see worse ROI (60-80%) - consider whether you'd be better moving to larger property instead.
Should I do side return and rear extension separately or together?
Do together if: (1) budget allows (£120k+ total), (2) staying 7+ years, (3) both are genuinely needed for functional space. Do separately if: (1) budget is £60k-80k (do side return first, adds most value per £), (2) uncertain about staying long-term, (3) want to test if side return alone gives enough space before committing to full wrap-around. Doing together saves 10-15% on total cost vs two separate projects (scaffolding, professional fees, disruption costs shared).
Do I need party wall agreements for wrap-around extensions?
Yes, almost certainly. Side return work requires party wall agreement with neighbor whose wall you're building against (£1k-£2k per side). Rear extension may require party wall if you're excavating foundations within 3m of neighbor's structure. Total party wall costs: £2k-£5k for both sides of terraced house. Can't avoid this - it's a legal requirement under Party Wall Act 1996. Start party wall process BEFORE construction (8-12 weeks notice period required).
What's the timeline for a wrap-around extension?
Total: 5-8 months. Design & planning application: 2-3 months. Planning decision: 8-13 weeks. Party wall: 8-12 weeks (can overlap with planning). Construction: 12-16 weeks. Add 2-4 weeks for kitchen installation and snagging. The planning permission requirement adds 3-4 months vs permitted development projects. Can't rush planning - attempting to start before approval is illegal and council can issue stop notice.
Summary
Wrap-around extensions are the most space-efficient way to extend Victorian terraced houses, combining side return (6-15m²) and rear extension (15-30m²) to create 40-50m² open-plan living spaces. They cost £130k-£185k all-in for mid-range finish, nearly always require planning permission, and add 15-20% property value (£100k-£180k on £600k-£900k homes).
Best for: Properties worth £600k+ with side return access, owners staying 7+ years, budgets of £120k+. Not suitable for: Properties under £450k (poor ROI), budgets under £100k, short-term ownership (under 5 years), conservation areas with strict constraints.
Start with architect consultation to assess feasibility, confirm planning requirements, and establish realistic budget. Factor 5-8 months total timeline including planning permission (3-4 months) and construction (3-4 months).