Two-storey wraparound extensions in Letchworth Garden City
A two-storey wraparound extension is one of the most space-efficient ways to add bedrooms and living space to a house in Letchworth Garden City, because the new floors share one set of foundations and one roof.
Before you start in Letchworth Garden City, here's what applies.
- Postcode districts
- SG6
- County / area
- Hertfordshire, England
- Price region
- East of England
- Guide price
- £124,000–£170,000 (£2,210–£3,040 per m²)
- Approval route
- Planning permission is needed: the side part takes it outside permitted development in England.
- Nearest towns
- Baldock (1.7 miles), Hitchin (3.2 miles), Henlow (4.3 miles)
- Distance to Watford
- about 23.5 miles
- First visit
- Free, no obligation
About a two-storey wraparound extension
A two-storey wraparound extension is an L-shaped addition that extends both the side and the rear of your house, on two floors. It gives one of the largest gains in floor space of any extension, typically a big open-plan kitchen and living area below and two or more bedrooms or bathrooms above. In England it needs planning permission, because the side part is more than one storey.
Letchworth Garden City sits about 23.5 miles from Watford. Closer to home, Baldock is 1.7 miles away and Hitchin 3.2 miles.
What it costs in Letchworth Garden City
For budgeting in Letchworth Garden City, allow around £124,000–£170,000 for a two-storey wraparound extension with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space). That's based on £2,210–£3,040 per m² including VAT for the East of England. Design fees, structural calculations and approval fees are separate and listed on our prices page.
| Spec | Per m² | An L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space) |
|---|---|---|
| Essential | £2,040–£2,800 per m² | £114,000–£156,500 |
| Standard | £2,210–£3,040 per m² | £124,000–£170,000 |
| Premium | £2,660–£3,650 per m² | £149,000–£204,000 |
Planning and building regulations in Letchworth Garden City
In England, a two-storey wraparound extension needs householder planning permission, because any extension beyond a side wall must be single storey to be permitted development. The application costs £548 (or £575 for applications made from 8 December 2026). Councils weigh the side part against the street scene and the rear part against neighbours' light and outlook, and should decide within 8 weeks of validation.
Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.
Design points for Letchworth Garden City homes
Phasing the build
A wraparound touches two sides of the house at once, so the kitchen and often the rear rooms are out of use for part of the build. We plan the sequence so you keep a working kitchen and bathroom for as long as possible, or advise when moving out briefly makes sense.
The corner post
At the outside corner of the L, there is no existing wall to carry the floor above. Opening the ground floor fully usually means a steel frame or a corner post, and the engineer's design sets how slim it can be. We decide early whether you want a clear corner or a visible post.
How we'd run your project
Look at the house
We start in Letchworth Garden City with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Design and approvals
We draw the extension and check it against the rules for England, then apply for planning permission or a certificate of lawfulness, whichever fits.
Detail and price
Construction drawings, engineer's calculations and building control sign-off, then a written fixed price for the build.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.
Questions about two-storey wraparound extensions in Letchworth Garden City
Which postcodes do you cover around Letchworth Garden City?
We cover Letchworth Garden City (SG6) and nearby places including Baldock, Hitchin and Henlow, plus the rest of Hertfordshire. The first site visit is free.
Who handles building regulations for a project in Letchworth Garden City?
We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
How much does a two-storey wraparound extension cost in Letchworth Garden City?
Our guide for the East of England, which covers Letchworth Garden City, is £2,210–£3,040 per m² including VAT. A typical project with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space) comes to about £124,000–£170,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
How much floor space does a wraparound extension add?
It depends on the width of the side plot and the depth at the rear. Our guide prices are based on a typical wraparound with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space). Yours may be larger or smaller, and the measured survey shows what your plot can take.
Does a wraparound extension need steel?
Almost always. Opening the corner of the house and the old rear wall to make one open-plan space means steel beams, and often a steel post or frame at the outside corner. The structural engineer sizes these, and the steel is ordered once the design is fixed, which is one reason a wraparound needs careful sequencing.
Nearby
We also cover places near Letchworth Garden City, including:
Other extensions in Letchworth Garden City
- Rear
- Side
- Part two-storey
- Over a garage
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Letchworth Garden City · Two-storey wraparound extensions across Hertfordshire
Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.