Hounslow single-storey extensions, designed and built
Planning a single-storey extension in Hounslow? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in HounslowFrom £27,000 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsTW1, TW2, TW3, TW4, TW5
How much does a single-storey extension cost in Hounslow?
Labour and material costs vary across the UK, so for Hounslow we use our London factor (×1.3). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Hounslow: £2,280 to £4,420 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £27,000 – £32,000 | £31,500 – £41,000 | £40,500 – £53,500 |
| 4 m × 5 m 20 m² | £45,500 – £53,500 | £53,000 – £68,000 | £67,500 – £88,500 |
| 5 m × 6 m 30 m² | £68,000 – £80,000 | £79,500 – £101,500 | £101,000 – £133,000 |
Try the guide-price tool to see a range for your own size and finish.
Working in Hounslow
We cover Hounslow and the postcode districts TW1, TW2, TW3, TW4, TW5, TW7. We also work in nearby Isleworth (1 mile), Heston (1 mile), Richmond (2 miles), Hanworth (3 miles).
For homes towards Surrey, West Molesey is around 5 miles away. In London, space is at a premium and gardens are often short, so side returns, wraparounds and carefully planned rear extensions tend to make the most of every metre.
Included in a typical project
- Foundations, drainage and groundworks
- Walls, steel beams and the new opening into the house
- Doors, windows, insulation, plastering and first fix to finish
- Flat or pitched roof, rooflights or lantern
- Planning route checked and the right approval obtained
- Measured survey and design
Depth is the big decision. Every extra metre adds floor area but also takes garden and can push you out of permitted development. We draw the room at two or three depths so you can see the trade-off in space, light and cost before anything is fixed.
Will the council need to approve it?
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
The planning position for a specific Hounslow address depends on its history and any designations, which is why we check it at the first visit.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
From first visit to completion
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Single-storey extension questions answered
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Hounslow, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of Hounslow?
Yes. We cover Hounslow and the surrounding parts of Greater London. Site visits are free and there is no obligation.
Do I need building regulations approval in Hounslow?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
How much does a single-storey extension cost per square metre?
Our guide range is about £2,280 to £4,420 per m² including VAT, depending on specification. A standard-spec 4 m × 5 m room usually lands at £53,000 to £68,000 in Hounslow, plus design and council fees.
Can I stay in the house during the build?
Usually yes. Most of the work happens outside until the final weeks, when we open the rear wall. We plan that stage carefully and seal the opening with a temporary screen to keep dust down.
Book a free site visit in Hounslow
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.