House Extensions Barking and Dagenham
Single storey rear and double storey extensions in Barking and Dagenham, planning, structure and build under one contract.
- Rated 4.9 from 31 reviews on MyBuilder
- Single-storey rear extension from £40,000
- Free site survey, itemised quote
GS Renovation plans and builds extensions throughout Barking and Dagenham, on the Becontree Estate and across Chadwell Heath and Dagenham. We handle groundworks, steel, roofing and the full fit-out, plus any dealings with Barking and Dagenham Council.
In Barking and Dagenham, a single-storey rear extension typically starts from £40,000, or £2,000 to £2,800 per m² (indicative London ranges, Architecture for London, Resi, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Barking and Dagenham: the structural engineer we appoint designs the structure, we build it, and building control signs it off.
Price guide
| Work | Indicative London range |
|---|---|
| Single-storey rear extension | from £40,000 |
| Rear extension, per m² | £2,000 to £2,800 |
| Side return, per m² | £2,400 to £3,200 |
| Wraparound, per m² | £2,400 to £3,200 |
| Double storey, per m² | £1,800 to £2,600 |
| Basement extension | see the basement page |
Indicative London ranges (Architecture for London, Resi, MyBuilder and Checkatrade, 2026), not a quotation. Prices checked September 2026. Full breakdown: Extension Costs & Planning.
Quick estimate for Barking and Dagenham
Barking and Dagenham range: choose above
Rear and side extensions in Barking and Dagenham
Most 1930s houses in this borough are terraced, which suits single storey rear extensions, and on end-of-terrace houses a side extension down the passage or a wrap-around that does both. We dig and pour the foundations, build up in blockwork or cavity brick, install any steel needed to carry the existing structure, then tie the new roof into the old.
The most asked-for project is a kitchen extension across the back of a terraced house, opening the old kitchen and back room into one kitchen-diner. On a mid-terrace the new flank walls sit on or near both boundaries, so party wall notices to both neighbours are usually part of the programme, and a single storey rear extension of up to 3 metres on an attached house can often go ahead under permitted development. We manage the whole build, from breaking ground to plastering, so the extension reads as part of the original house rather than an obvious add-on.
Housing in Barking and Dagenham
The Council Tax list puts Barking and Dagenham at about 81,800 homes, 36% flats against 64% houses; 4% went up before 1919, 50% between the wars and 46% after 1945. 55% of homes here are terraced; a rear extension on a terrace in Barking and Dagenham digs foundations close to both neighbours, so notices to both are normal.
Sizing a Barking and Dagenham rear extension before drawings start
The Barking and Dagenham 2037 Local Plan was adopted at Assembly on 18 September 2024, and where an extension needs planning permission, the council's Residential Extensions and Alterations SPD sets two limits worth knowing before any drawing. For a terraced or semi-detached house it says a single storey addition at the back should not normally go deeper than 3.65 metres, and no extension should normally take up more than 50% of the garden. Measure both on your own plot first. The depth runs from the original back wall, so an older kitchen addition uses some of it, and a short garden can reach the half limit first.
In a conservation area, two more steps come before the build. The council's consent is needed to demolish, in whole or part, buildings and structures in a conservation area, including walls and outhouses. An old outhouse or garden wall in the way of the extension is therefore a consent question, not just a skip. Felling, lopping, topping or uprooting a tree in a conservation area needs six weeks notice in writing to the council. On a Barking and Dagenham plot where a tree stands near the new foundations, give that notice before the design is fixed.
Planning and permitted development in Barking and Dagenham
Many single storey rear extensions on Becontree and Dagenham houses fall under permitted development, which means no full planning application, though the work still needs building regulations approval and inspection. Larger schemes, most double storey extensions, and anything altering the front or affecting a protected setting will need a planning application to Barking and Dagenham Council.
We assess your specific property early and tell you honestly which route applies. Where the extension sits against the boundary or affects the shared wall of an attached house, the Party Wall Act also comes into play, and you serve those notices as building owner with the drawings we supply. We coordinate the drawings, the council submission where needed and building control into one clear programme.
Kitchen extensions in Barking and Dagenham
86% of the houses in Barking and Dagenham are terraced. On a terrace the kitchen extension is built out from the back, into the side return where the house has one or across the full rear width, and a steel beam takes the old back wall so the kitchen and the new room become one space. The fit-out is priced on its own page, kitchen renovation in Barking and Dagenham; the build figures are in the table above.
Side return extensions in Barking and Dagenham
Side returns belong to Victorian and Edwardian terraces, and only 4% of homes in Barking and Dagenham predate 1919, so they are the exception here; most extensions run across the full rear width instead. Our side return extension page covers the build in detail, with build rates of £2,400 to £3,200 per m².
Double storey extensions in Barking and Dagenham
Under permitted development a two-storey rear extension can go no more than 3 metres beyond the original rear wall and must stay at least 7 metres from the rear boundary, and in a conservation area it is not permitted development at all. Many gardens are too short for the 7 metre rule, so a double storey extension in Barking and Dagenham often needs planning permission from Barking and Dagenham Council. On the 55% of homes that are terraced, the neighbours' windows usually decide the depth. Barking and Dagenham has four conservation areas: Abbey and Barking Town Centre, Abbey Road Riverside, Chadwell Heath Anti-aircraft Gun Site and Dagenham Village (council source). Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.
- Insulation, airtightness and thermal detailing to regulations
- Brickwork and mortar matched to the existing elevation
- Full fit-out, finishing and making good
VOA Council Tax stock of properties, March 2025, for all 22 statistical areas in Barking and Dagenham. Counts rounded by the VOA.
Trusted House Extensions in Barking and Dagenham
Homeowners across Barking and Dagenham choose GS Renovation because we take an extension from foundations to final coat as one accountable team. We know the borough's interwar plots, we are straight about permitted development versus a council application, and our founder's 30+ years of building means solid groundworks, correctly sized steel and a tidy site.
- Building control inspected at foundation, damp course and steel stages
- Paperwork and certificates handed over for when you sell
- Drainage diverted or built over with the right approval in place
Built a new extension at rear of property. Laid foundations, drainage, raised floor, new roof and completed all fixtures and interior decoration…
Giorgio is an excellent and intelligent workman, and with very reasonable prices! He installed a kitchen extractor fan in a complicated situation…
George was very friendly and helpful from start to finish. He worked really hard to ensure our kitchen was installed to a high standard and was…
FAQ
Frequently Asked Questions about House Extensions Barking and Dagenham
What should I budget for house extensions in Barking and Dagenham?
A Barking and Dagenham budget for house extensions should sit within £2,000 to £2,800 per m² for a rear extension (indicative) and add a contingency for what the IG11 survey cannot see. In interwar housing the unknowns sit behind plaster and under floors, so GS Renovation prices what is visible and names the rest. The Barking and Dagenham Council building control fee belongs in the same budget.
Will my rear extension in Dagenham need planning permission from the council?
Often not. Many single storey rear extensions on interwar houses in Dagenham are permitted development, so no full application is needed, but they still require building regulations approval. Larger or double storey schemes, and anything altering the front, usually need a planning application to Barking and Dagenham Council. We check your property and confirm the correct route before we start.
Can I build my Dagenham extension over the drain at the back of the house?
Possibly, but it needs checking early. In terraced streets the drain behind the houses is often a shared run serving several properties, which makes it a public sewer, and building over or near one needs the water company's consent under Part H. Private drains can usually be diverted or protected with a manhole inside the new floor. A drainage survey before design avoids redrawing everything later.
Does digging foundations for a Barking extension mean notifying my neighbour?
Often it does. A trench dug within 3 metres of next door's building and taken below the depth of their footings brings in the Party Wall etc. Act 1996, with one month's notice. Along the shared boundary of an attached house that is nearly always the case. If they decline to agree, surveyors draw up an award before digging, so the notice should go out, from you as building owner or your surveyor, while the drawings are still being finished.
Is there a limit on glazing in a Barking and Dagenham extension?
More than you might think, but Part L has a say. A new extension must meet current insulation standards, and very large areas of glass or rooflights can push the design over the permitted heat loss. The usual fix is better-performing glazing, extra wall or floor insulation elsewhere, or a calculation showing the whole extension still complies. We settle this before ordering doors or lantern roofs.
Can we keep living in our Dagenham house while the extension goes up?
Yes, for most of the build. The new walls, roof and windows go up outside while your existing back wall stays in place, so the house remains sealed. The disruptive stage is when that rear wall is opened and a beam goes in to join old and new, usually a few days with the kitchen out of action. We time the kitchen fit straight after, so you are not without one for long.
Do the Becontree Estate rules apply to an extension elsewhere in Barking and Dagenham?
No. They apply only inside the estate, so check which side of its boundary your house sits. The council says the Becontree Estate was built from 1921 to 1934 comprising approximately 29,000 homes. Within it, the Becontree Estate SPD and Design Code adopted on 16 June 2026 is a material consideration, and porches lose permitted development rights under an Article 4 direction due in November 2026. The borough-wide Residential Extensions and Alterations SPD applies on both sides of the line.
Does knocking down a garage for an extension need notice in Barking and Dagenham?
Ask first. Barking and Dagenham says it is an offence to begin any demolition without giving notice, and at least six weeks notice must be given. Whether your garage falls within that is a question for Be First Building Control, and the answer shapes the start date. Use the six weeks for the drainage survey and trial holes, so the foundation design is ready when the garage comes down.
Is a building notice enough for a Barking and Dagenham rear extension?
It can be, but check the drains first. Building notices can be used for minor domestic works such as extensions, but not for buildings within three metres of a public sewer. Behind a terrace the shared drain can be a public sewer, so the survey decides the route. Where full plans applies, the decision can take up to five weeks, which belongs in the programme from the start.
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