Letchworth Garden City, Hertfordshire
Single-storey rear extension in Letchworth Garden City
For homes in Letchworth Garden City, a single-storey rear extension is often the simplest way to gain space without moving. Ground-floor space across the back of the house, usually for a kitchen, dining or family room. We take it from survey to completion certificate.
Letchworth Garden City and its postcode districts SG5, SG6 and SG7 are part of our Hertfordshire coverage. A depth of 3 to 4 metres keeps many single-storey rear extensions in Letchworth Garden City within permitted development, subject to the house's planning history.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a single-storey rear extension cost in Letchworth Garden City?
Guide prices for a single-storey rear extension in Letchworth Garden City start from our East of England rate of £2,010–£3,290 per square metre, including VAT. East of England prices run slightly above our West Midlands baseline; clay soils near trees are the main foundation variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £24,000–£39,500 |
| 4 m wide × 5 m deep (20 m²) | £40,500–£65,500 |
| 4 m wide × 6 m deep (24 m²) | £48,500–£79,000 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a single-storey rear extension in Letchworth Garden City?
Planning for a single-storey rear extension in Letchworth Garden City follows the English householder rules.
In England a single-storey rear extension can often be built under permitted development: up to 3 metres beyond the original rear wall of an attached house, or 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres if any part is within 2 metres of a boundary.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. Before any drawing we look up the property's history with the council, because earlier extensions and removed rights change the answer.
What are homes in Letchworth Garden City like to extend?
Post-war semis and newer estates are typical of Letchworth Garden City, and many have room for a full-width extension. Shrinkable clay is common in the East of England, so foundations near trees and hedges are designed to NHBC-style depth guidance.
How a single-storey rear extension in Letchworth Garden City comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Single-storey rear extensions near Letchworth Garden City
Neighbouring places we cover include Baldock (1.7 miles) and Hitchin (3.2 miles).
- Single-storey rear extension in Baldock
- Single-storey rear extension in Hitchin
- Single-storey rear extension in Henlow
- Single-storey rear extension in Stevenage
- Single-storey rear extension in Biggleswade
Other work in Letchworth Garden City:
FAQ
Single-storey rear extension questions in Letchworth Garden City
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Can you match the brick or stone on my Letchworth Garden City house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
Will the extension make the room behind it dark?
Not if it is designed well. Rooflights or a lantern over the old back room, and a wide opening into it, keep daylight reaching the middle of the house.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
How long does a rear extension take to build in Letchworth Garden City?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
Is the site visit in Letchworth Garden City free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.