Hounslow, Greater London
Single-storey rear extension in Hounslow
Ground-floor space across the back of the house, usually for a kitchen, dining or family room. If you live in Hounslow and want to know what a single-storey rear extension would cost and whether it needs planning, start with the online guide price or a free site visit.
Hounslow and its postcode districts TW3, TW4, TW5 and TW7 are part of our Greater London coverage. A depth of 3 to 4 metres keeps many single-storey rear extensions in Hounslow 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 Hounslow?
A single-storey rear extension in Hounslow is priced at £2,470–£4,030 per square metre including VAT as a guide, before kitchen fit-out and fees. London prices sit at the top of our range because of labour rates, access through the house, parking suspensions and skip licences.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £29,500–£48,500 |
| 4 m wide × 5 m deep (20 m²) | £49,500–£80,500 |
| 4 m wide × 6 m deep (24 m²) | £59,500–£96,500 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a single-storey rear extension in Hounslow?
Whether your single-storey rear extension in Hounslow needs a planning application depends on its size, your house and any local restrictions.
Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it is within 2 metres of a boundary.
If 3 or 4 metres is not enough, England's prior approval route allows 6 metres on a terraced or semi-detached house and 8 metres on a detached house for a single-storey rear extension. Neighbours are consulted, the council decides within 42 days, and the fee is £249, rising to £310 from 8 December 2026.
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 Hounslow like to extend?
Hounslow is mostly 1930s semis, short terraces and post-war houses, so full-width single-storey and two-storey rear extensions are realistic on many plots. Some later estates had permitted development rights removed by condition, so we check the planning history first.
How a single-storey rear extension in Hounslow 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 Hounslow
We also build single-storey rear extensions in nearby Osterley (0.9 miles) and Isleworth (0.9 miles).
- Single-storey rear extension in Osterley
- Single-storey rear extension in Isleworth
- Single-storey rear extension in Heston
- Single-storey rear extension in Cranford
- Single-storey rear extension in Richmond
Other work in Hounslow:
FAQ
Single-storey rear extension questions in Hounslow
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.
Do you handle building control in Hounslow?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
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.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
Is the site visit in Hounslow free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.