Chiswick side extensions, designed and built
Our design and build teams take on side extensions in Chiswick, from the first measured survey through planning and building control to the finished room.
- Guide price in ChiswickFrom £28,500 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsSW13, SW14, W3, W4, W6
What should I budget for a side extension in Chiswick?
Labour and material costs vary across the UK, so for Chiswick we use our London factor (×1.3). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Chiswick: £2,280 to £4,420 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £28,500 – £34,500 | £31,500 – £41,500 | £40,500 – £53,500 |
| 3 m × 6 m 18 m² | £40,500 – £49,500 | £47,500 – £62,500 | £60,500 – £80,000 |
| 3 m × 8 m 24 m² | £54,500 – £66,000 | £63,500 – £83,000 | £81,000 – £106,500 |
For a figure based on your own dimensions, use our guide-price tool.
Will the council need to approve it?
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
Extensions in and around Chiswick
Our survey diary covers Chiswick, including SW13, SW14, W3, W4, W6, W12. Nearby, we also take on projects in Acton (1 mile), Barnes (1 mile), Shepherds Bush (2 miles), Notting Hill (3 miles).
East Molesey, in Surrey, is roughly 8 miles from Chiswick and also on our list. 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.
What is included
- Structure, roof tied into the house
- Windows, doors and finishes to match
- Planning route checked or application made
- Foundations near boundaries and any drains
- New openings through the side wall
Councils often prefer side extensions to sit slightly back from the front of the house with a lower roof, so the original building still reads clearly. We design to those principles from the start to avoid redesigns.
How the project works
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
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions people ask about side extensions
Who do I contract with for a side extension in Chiswick?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do you cover all of Chiswick?
Yes. We cover Chiswick and the surrounding parts of Greater London. Site visits are free and there is no obligation.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Chiswick, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How much does a side extension cost?
Our guide range is about £2,280 to £4,420 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £47,500 to £62,500 in Chiswick.
How close to the boundary can I build?
It depends on height. In England, within 2 m of a boundary the eaves must not exceed 3 m under permitted development. Building on the boundary is possible but brings party wall and maintenance access issues we plan for.
Book a free site visit in Chiswick
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.