Wrap Around Extension Cost UK (2026): L-Shaped Prices per m²

What is a wrap around extension?

A wrap around extension is an L-shaped extension that combines a side extension (on a terrace, usually a side return infill) with a rear extension in one build. The two parts meet at a corner, creating one large open-plan space – typically a kitchen, dining and family room that spans the full width of the house and opens onto the garden.

On Victorian and Edwardian terraces, a wrap around fills the side return and extends beyond the rear of the outrigger. On semi-detached and detached homes, it wraps around a back corner of the house, using space along the side as well as the garden. Either way, you get far more floor area than a side return alone, without losing as much garden as a deep rear extension.

Wrap around extension cost per m²

Wrap arounds cost a little more per m² than a simple rear extension. The corner where the side and rear sections meet usually needs a steel frame or corner post to carry the roof once the original walls are removed, and the roof itself is more complex, with more junctions to weatherproof.

Finish level	Cost per m² (ex VAT)	Typical specification
Basic	£1,900 – £2,300	Flat roof with rooflights, French doors or a single set of bi-folds, single steel and corner post
Standard	£2,300 – £2,900	Flat roof with a lantern or pitched glazed side section, aluminium sliders, steel goalpost frame
High-end	£2,900 – £3,700	Large frameless glazing, structural glass roof, underfloor heating, bespoke joinery

Other sources sit in a similar range, though they define their figures differently. One BestBuilders guide puts wrap arounds at £2,000–£2,800 per m², about £100–£200 per m² above its single storey rate, and its more detailed August 2026 guide gives an all-in £2,600–£3,800 per m² for 30–40m² projects including fees. Homebuilding & Renovating says to expect the higher end of the general £2,200–£3,300 per m² extension range because of the structural complexity. Smaller wrap arounds cost more per m², because the corner steelwork and design costs are much the same regardless of size.

Single storey wrap around extension cost by size

All-in totals below are what our calculator produces for a standard finish in the Midlands, including design, a structural engineer, building control, a householder planning application and 20% VAT.

Combined floor area	Example layout	Build cost (ex VAT)	All-in inc. fees, planning & VAT
20m²	Side infill 1.5m × 6m plus rear 3m × 3.7m	£45,000 – £57,000	£58,000 – £78,000
25m²	Side infill 2m × 6m plus rear 3m × 4.3m	£56,500 – £71,000	£72,000 – £96,000
30m²	Side infill 2m × 6m plus rear 3m × 6m	£67,500 – £85,500	£86,500 – £114,500
35m²	Side 2.5m × 6m plus rear 3.5m × 5.7m	£79,000 – £99,500	£100,500 – £132,500
40m²	Side 2.5m × 7m plus rear 4m × 5.6m	£90,000 – £113,500	£114,500 – £151,000
50m²	Side 3m × 8m plus rear 4m × 6.5m	£112,500 – £142,000	£142,500 – £187,500

BestBuilders’ August 2026 figures for all-in costs excluding kitchen units are similar: £72,000–£105,000 for a 20–25m² wrap around and £90,000–£130,000 for 30–40m².

L-shaped extension cost by finish level

Finish	Build cost (ex VAT)	All-in total
Basic	£56,000 – £67,500	£71,500 – £92,000
Standard	£67,500 – £85,500	£86,500 – £114,500
High-end	£85,500 – £109,000	£108,500 – £144,500

Because almost every wrap around becomes a kitchen-diner, add the kitchen too: roughly £8,000–£15,000 for a budget kitchen, £15,000–£30,000 mid-range and £30,000–£50,000 high-end, plus VAT. See our kitchen extension cost guide for more detail.

Wrap around extension costs by region

Region	Standard per m² (ex VAT)	30m² wrap around, all-in
London	£2,875 – £3,625	£109,500 – £144,500
South East	£2,575 – £3,250	£98,500 – £130,000
South West & East of England	£2,390 – £3,015	£91,500 – £121,000
Midlands	£2,255 – £2,840	£86,500 – £114,500
North of England & Wales	£2,115 – £2,670	£81,000 – £108,000
Scotland & Northern Ireland	£2,210 – £2,785	£84,500 – £112,000

BestBuilders’ regional data for a 25m² wrap around follows the same pattern, from about £95,000–£125,000 in London down to £65,000–£88,000 in the North East.

Full cost breakdown

These are the main items that make up a wrap around budget. The structural, roof and glazing items are already included in the per-m² build rates; they are shown separately so you can see where the money goes.

Cost item	Typical cost
Build (standard finish)	£2,300 – £2,900 per m² ex VAT
Single 5–7m steel with padstones and fire protection	£2,800 – £5,500
Goalpost frame (three steels) including engineer	£6,500 – £11,000
Flat roof (single-ply or GRP)	£4,500 – £8,000
Hybrid roof with lantern and pitched glazed section	£11,000 – £18,000
Aluminium bi-folds (three panels)	£3,500 – £6,500
Premium 4–6m sliding doors	£6,500 – £15,000
Architectural design	4 – 7% of build cost
Structural engineer	£500 – £2,500
Building control	£600 – £1,200
Householder planning application	£548 (no VAT)
Party wall surveyor	£1,000 – £3,000 per neighbour
VAT	20% on build and fees
Contingency	10% recommended

On a 30m² standard project in the Midlands, design, engineering and building control fees come to about £4,000–£9,500, and VAT adds £14,500–£19,000. A 10% contingency takes the recommended budget to roughly £95,000–£126,000.

What affects the cost of a wrap around extension?

The corner structure

The defining feature of a wrap around is the open corner. Removing both the side wall of the outrigger and the rear wall of the house means the structure above must be carried on steel – either a corner post or a goalpost frame. Going completely post-free, so that glass meets glass at the corner, needs heavier steel and costs more again.

Roof design

A single flat roof over the whole L-shape is the cheapest option. Many designs use a pitched glazed roof over the side section and a flat roof with a lantern over the rear, which adds cost and more junctions to detail properly.

Glazing

Glazing is often the biggest variable. BestBuilders notes glazing packages on wrap arounds “routinely reach five figures”, with frameless sliders from £15,000–£35,000+.

Foundations and drainage

A wrap around covers a large area, so it is more likely to meet drains, tree roots or poor ground. BestBuilders puts strip foundations for a 25m² wrap around at £6,500–£11,000, with reinforced foundations or piling on poor ground adding £8,000–£18,000.

Party walls

On a terrace, the side section usually sits on or near one boundary and the rear section may be near the other, so you can need awards with both neighbours.

Location

The same project costs around a third more in London than in the North of England.

Wrap around extension planning permission

Most wrap around extensions in England need a householder planning application. Under permitted development, the side and rear sections are assessed against both sets of rules, so every part of the extension must comply with:

• Rear limits: single storey, no more than 3m beyond the original rear wall (4m for a detached house), maximum height 4m, and eaves no higher than 3m within 2m of a boundary.
• Side limits: single storey, maximum height 4m, and no wider than half the width of the original house.
• Overall: extensions and outbuildings must not cover more than half the land around the original house, and materials must match.

Homebuilding & Renovating notes that while a small side and rear extension may be possible under permitted development, the size of a typical wrap around makes it an unlikely candidate. Side extensions are not permitted development at all on designated land such as conservation areas, and flats and maisonettes have no permitted development rights. If you believe your design does qualify, get a lawful development certificate (£274) before building.

The planning fee in England is £548 from April 2026, and councils aim to decide householder applications within 8 weeks. Building regulations approval is needed either way, and the Party Wall etc. Act 1996 will usually apply. Read our extension planning permission guide for more detail.

Single storey vs double storey wrap around

Most wrap arounds are single storey. A two storey wrap around is possible on detached and some semi-detached houses, but it always needs planning permission (two storey side extensions are never permitted development) and is harder to get approved because of its bulk. Our two storey extension cost guide covers double storey rates, which are lower per m² because the foundations and roof serve two floors – but expect a premium on top for the more complex corner structure and roof.

How long does a wrap around extension take?

1. Design and planning drawings: 6–12 weeks
2. Planning permission: 8 weeks target from validation, often longer
3. Structural design, tender and party wall notices: 1–3 months
4. Build on site: roughly 12–20 weeks; BestBuilders quotes 12–16 weeks and Homebuilding & Renovating four to six months for a single storey wrap around

From concept to completion, BestBuilders puts a typical project at 10–14 months.

Wrap around vs side return or rear extension

If budget is tight, compare a wrap around with its two halves. Our standard-finish rates are £2,200–£2,700 per m² for a single storey rear extension, £2,500–£3,100 per m² for a side return extension and £2,300–£2,900 per m² for a wrap around. Doing both together is usually cheaper than building a side return now and a rear extension later, because you pay for design, approvals, site set-up and the kitchen only once.

How to save money on a wrap around extension

• Accept a corner post. A slim steel post at the corner is much cheaper than a fully post-free glass corner.
• Use one roof type – a flat roof with a lantern or long rooflight – rather than mixing pitched glazing and flat roofing.
• Prioritise glazing on the garden elevation, where it adds most, and keep side glazing simpler.
• Keep the kitchen sink and appliances near existing drains.
• Get a full tender pack with structural drawings so builders price the same job.
• Engage neighbours early to avoid two sets of party wall surveyor fees.

Does a wrap around extension add value?

A wrap around creates the large, light kitchen-diner that buyers of family homes look for, so it usually adds value. Nationwide’s research (October 2025) found that a 10% increase in floor space adds about 5% to a typical home’s value. On a three-bedroom terrace of around 90m², a 30m² wrap around is a 33% increase in floor space. BestBuilders reports return-on-investment of around 1.25–1.5 times cost on £400,000–£800,000 homes, but returns are lower where house prices are lower, so check sold prices for extended homes nearby. For a wider comparison of options, see our house extension cost guide.

Frequently asked questions

How much does a wrap around extension cost in 2026?

Most wrap arounds cost £2,300–£2,900 per m² at a standard finish, excluding VAT. A 30m² single storey wrap around costs about £86,500–£114,500 including fees and VAT in the Midlands, or £109,500–£144,500 in London.

Do wrap around extensions need planning permission?

Usually. Every part of the extension must meet both the side and rear permitted development limits, which most wrap arounds exceed. Side extensions are not permitted development in conservation areas.

How much does an L-shaped extension cost?

An L-shaped extension is the same as a wrap around. Expect about £58,000–£78,000 all-in for 20m² and £114,500–£151,000 for 40m² outside London at a standard finish, excluding a kitchen.

Is a wrap around extension more expensive than a rear extension?

Yes, slightly per m² – about £100–£200 more at a standard finish – because of the corner steelwork and more complex roof. It also tends to be larger, so the total is higher.

How long does a wrap around extension take to build?

Typically 12–20 weeks on site. Including design, planning and party wall notices, allow around 10–14 months.

Can you do a wrap around extension on a semi-detached house?

Yes. On a semi, the extension wraps around the back corner on the side away from your neighbour, using a side driveway or strip of garden. A party wall agreement may still be needed for the rear section.

Related guides: Rear extension cost · Side extension cost · Party wall agreements

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