A double-storey extension adds two floors of new space to your house in one build, typically a larger kitchen or living room downstairs with an extra bedroom, bathroom or en-suite above, sharing one set of foundations and one roof.
Homeowners in Chessington usually consider a double-storey extension for one of a few reasons: something has worn out, the house no longer suits the way they live, or they are getting it ready to sell. We visit, agree a specification and put a fixed price in writing. Most jobs like this take 14–22 weeks on site, and we work across London, including Hook, Surbiton and Ewell.
- Guide price
- £78,000–£156,000 inc VAT
- Time on site
- 14–22 weeks on site
- Postcodes
- KT5, KT6, KT7, KT9 and KT10
- Planning rules
- England
- Local area
- Greater London
- Survey
- Free, with a written quote
How much does a double-storey extension cost in Chessington?
The table below shows guide prices for a double-storey extension in Chessington. They are based on rates in London, which run about 30% above the national guide, giving an overall range of £78,000–£156,000. All figures include VAT and are firmed up after a free site survey.
| Type of job | What it usually involves | Guide in Chessington |
|---|---|---|
| Small (15–20m² total) | A compact rear or side extension adding a small room on each floor. | £52,000–£84,000 |
| Typical (30–40m² total) | A larger kitchen or living room below with a double bedroom or en-suite above. | £78,000–£156,000 |
| Large (50m² plus total) | Wide or deep extensions, often with a new bathroom, steelwork and high-spec glazing. | £130,000–£234,000 |
Your price depends mostly on:
- How the new roof joins the existing roof
- Bathrooms, en-suites and plumbing on the upper floor
- Foundation depth, ground conditions and drains to divert
- Scaffolding duration, access and the level of finishes
What do you get?
- Groundworks, foundations and below-ground drainage
- Insulated cavity walls with brick or render to match the house
- Roof structure tied into the existing roof, tiled to match
- Electrics, plumbing and heating by qualified trades, with certificates
- Windows, external doors, plastering and internal doors
- Building control inspections and completion certificate
Building in Chessington
London's housing is dominated by Victorian and Edwardian terraces, often in yellow London stock brick, with Georgian terraces in central districts and mansion blocks across many inner areas. Outer boroughs have large belts of interwar semis, and there are extensive post-war council estates. Many houses have been split into flats, and conservation areas are widespread.
Terraces suit side-return extensions and rear dormer loft conversions; interwar semis commonly take hip-to-gable lofts. Shared party walls, restricted parking and conservation rules often shape the plans and the programme.
For a double-storey extension in Chessington, this means checking things like wall construction, roof structure and existing services before we put a figure on paper.
Planning and building rules in Chessington
The notes below cover England, which is where Chessington sits. Rules change and every property is different, so we speak to the council before pricing your job.
In England, a two-storey rear extension can only be permitted development if it is no more than 3 m deep, at least 7 m from the rear boundary and finished to match the house. Most double-storey and all two-storey side extensions need full planning permission.
Building Regulations approval is needed, with structural calculations for beams, foundations and the roof. The Party Wall etc. Act 1996 often applies on semi-detached and terraced houses.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
From survey to handover
A visit to your home
Book a visit and we'll come to you. The survey covers measurements, the state of what's there now and any obvious constraints, so the price that follows is based on your actual home, not an average.
Quote in writing
After the survey we send a quote for a double-storey extension that fixes the price for the scope we've agreed. If you want to change materials or scope, we revise it in writing before anything is booked.
Getting ready
With the quote agreed, we book the work in and handle preparation: permissions where needed, building control notifications, material orders and access arrangements for your Chessington property.
The work itself
The work is carried out to the agreed specification, with floors and furniture protected and the site kept tidy. At the end we clean up, walk through the finished job with you and hand over any certificates.
What you can expect from us
Frequently asked questions
Will the extension affect my neighbours?
A double-storey extension can affect neighbours' light, outlook and privacy, which is why planning departments look closely at height, depth and window positions. Side windows facing neighbours often need obscure glass. Work near a shared wall may also need party wall notices; the Party Wall etc. Act 1996 applies in England and Wales only. We talk through these points early so the design is realistic.
How long does a double-storey extension take?
A double-storey extension typically takes 14–22 weeks on site, depending on size, roof design and weather. Foundations and ground-floor walls come first, then the first-floor joists, upper walls and roof. Once it is weathertight, electrics, plumbing, plastering and finishes follow. Allow extra time beforehand for drawings, calculations and approvals. We give you a stage-by-stage programme with your quote.
How long will a double-storey extension take?
On a typical home, allow 14–22 weeks on site. Larger projects, older buildings and extra work found once things are opened up can extend that, while simpler jobs may be shorter. Your quote includes an estimate of time on site, and your point of contact keeps you updated on the programme as the work progresses.
Do I need planning permission for a two-storey extension?
Most two-storey extensions need planning permission, but it depends on the size, height and position, your home's location, whether it is listed or in a conservation area, and which UK nation you are in. In England, a two-storey rear extension can sometimes be built under permitted development if it is no deeper than 3m and at least 7m from the rear boundary. We check what applies before quoting.
Can I stay at home during the work?
In most cases, yes. Most people can live at home throughout, and we plan the work to keep disruption down by protecting floors, agreeing working hours and keeping access routes clear. Bigger jobs affecting kitchens, bathrooms or heating may mean a short spell with reduced facilities, and we talk this through with you at the survey.
Near Chessington
Coverage for Chessington spans KT5, KT6, KT7 and KT9. Close by, Hook, Surbiton and Ewell are covered too, and the rest of our UK-wide area follows the same survey-then-quote process from start to finish.