Double-storey extensions in Becontree
Becontree homeowners can use us for the whole double-storey extension project: survey, design, planning or permitted development checks, building regulations and the build itself.
- Guide price in BecontreeFrom £49,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsE20, IG3, RM6, RM8, RM9
Included in a typical project
- Building regulations drawings and structural design
- Breaking through at both levels, stairs and landing changes where needed
- Foundations sized for two floors
- Householder planning application where needed
- Measured survey, design and planning drawings
What should I budget for a double-storey extension in Becontree?
Prices below are for Becontree, using the London factor of ×1.3. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Becontree: £2,020 to £3,900 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m, two floors 24 m² | £49,000 – £59,000 | £56,000 – £73,500 | £71,500 – £94,000 |
| 4 m × 4 m, two floors 32 m² | £64,000 – £77,000 | £74,500 – £98,000 | £95,500 – £125,000 |
| 4 m × 6 m, two floors 48 m² | £96,500 – £115,500 | £112,000 – £147,000 | £143,500 – £187,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
Covering Becontree
Our survey diary covers Becontree, including E20, IG3, RM6, RM8, RM9, RM10. Nearby, we also take on projects in Dagenham (2 miles), Barking (2 miles), Ilford (2 miles), Romford (3 miles).
Just over the Essex border, South Ockendon is about 7 miles away. London's housing is dominated by Victorian and Edwardian terraces, many with a rear outrigger and a side return, and 1930s semis in the outer boroughs. Conservation areas are common, so the planning check comes first.
Planning rules that apply in Becontree
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
The planning position for a specific Becontree address depends on its history and any designations, which is why we check it at the first visit.
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.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
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
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions people ask about double-storey extensions
Do I need building regulations approval in Becontree?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Do you cover all of Becontree?
Yes. We cover Becontree 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 Becontree, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Does a double-storey extension need planning permission?
Often, yes. In England a two-storey rear extension can be permitted development only if it projects no more than 3 m and sits at least 7 m from the rear boundary, with matching roof pitch and obscure side windows. Side extensions over one storey always need planning permission. We confirm the route at the survey.
Is a two-storey extension cheaper per square metre?
Usually. Our guide range is about £2,020 to £3,900 per m² of new floor area including VAT, compared with £2,280 to £4,420 per m² for single-storey work, because the foundations and roof are shared across two floors.
Book a free site visit in Becontree
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.