House Extensions Stratford
Single storey rear and double storey extensions in Stratford, 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 builds house extensions across Stratford and the wider E15 area, working on the Victorian terraces towards Forest Gate and West Ham Park as well as homes near the Queen Elizabeth Olympic Park. We manage the groundworks, steel, roof and full fit-out of single and double storey extensions from first drawing to final coat.
In Stratford, 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 Stratford: 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 Stratford
Stratford range: choose above
Rear and side-return extensions in Stratford
Stratford's Victorian and Edwardian terraces, about a quarter of its homes, are where most house extensions here happen: a rear extension across the back, a side-return infill along the narrow alley, or a wrap-around that combines both. We dig and pour the foundations, build up the walls and drop in the steel beam that carries the original rear wall once it opens into the new space. The result is the bright open-plan kitchen-diner that terraced plots rarely have otherwise.
Whether your extension is permitted development or needs a full planning application depends on the property. Many single storey rear extensions fall under permitted development, but flats have no permitted development rights at all, and in a conservation area side and two-storey extensions need permission from Newham Council. We check the rules for your address first and coordinate the drawings and application with your architect or designer if one is required, so nobody is caught out after the footings go in.
Housing in Stratford
The valuation list shows roughly 17,020 homes in Stratford, of which 27% are pre-1919, 1% interwar and 71% post-1945, split 71% flats to 29% houses. Where most homes are flats, a flat in Stratford has no householder permitted development rights, so extending one needs planning permission and the freeholder's consent.
Extending a Stratford house in or near a conservation area
The three Stratford conservation areas on Newham's list are St John's and Sugar House Lane in E15 and University, and St Johns dates from a Newham Council designation in January 1984. Inside any of them, planning permission can be needed for work that would otherwise go ahead without it. Permitted development there no longer covers a side extension, a rear extension of more than one storey or cladding, so a wraparound or two-storey scheme that would be permitted on the next street needs an application. A single storey rear extension within the normal limits can still go ahead without one. Check the address before any design work, because the answer decides whether the drawings are for a permitted development check or a planning submission.
Since the LLDC handed its planning powers back on 1 December 2024, every Stratford application is decided by the London Borough of Newham. Newham's Altering and Extending your Home SPD sets out documents that are mandatory for all householder planning applications at the point of submission, so that list shapes the drawing package. For a scheme with any doubt, Newham's Category A pre-application service gives written advice on residential extensions, and a 30 minute MS Teams meeting can be added. It has to be sought before work starts.
Extending leasehold homes near the Olympic Park
Extending a flat in a new-build or post-war block near the Olympic Park is far more constrained than extending a house. Structural change is limited, permitted development rights do not apply to flats, and the freeholder controls the exterior of the building. Where an extension or alteration is possible at all, it runs through the freeholder's licence to alter and the managing agent, alongside any planning application to the council.
For the terraced houses that make up much of Stratford's older stock, party wall matters come into play the moment you build near or onto a shared boundary. You serve the notices as building owner, or your surveyor does, and any schedule of condition is agreed through that process; we give you the drawings and programme the notices need and keep the works within the award. Building control then inspects the foundations, the steel and the drainage as the extension goes up, entirely separately from the planning side.
Kitchen extensions in Stratford
71% of homes in Stratford are flats, and a flat has no householder permitted development, so a ground-floor flat's kitchen extension needs planning permission from Newham Council and the freeholder's consent. Most kitchen extensions here are on the 29% of homes that are houses. The fit-out is priced on its own page, kitchen renovation in Stratford; the build figures are in the table above.
Double storey extensions in Stratford
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 Stratford often needs planning permission from Newham Council. It is a job for the 29% of homes that are houses; a flat cannot add a storey this way. Newham lists Romford Road conservation area in Forest Gate, and Stratford St John's and Sugar House Lane conservation areas in Stratford E15 (council source). Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.
- Bi-fold, sliding and French door openings to the garden
- Flat and pitched roofs with rooflights or lanterns
- Planning applications and permitted development assessments
VOA Council Tax stock of properties, March 2025, for Stratford East, Stratford Central, West Ham & Stratford Park and Carpenters Estate & Stratford New Town. Counts rounded by the VOA.
Why Choose GS Renovation in Stratford
Stratford homeowners choose GS Renovation because we run the whole extension under one roof: groundworks, steelwork, roofing and the fit-out of kitchen, bathroom and services. We tell you honestly whether your project is permitted development or needs a planning application to Newham Council before any commitment. Our founder's 30+ years on the tools means fewer surprises and a build that lasts.
- Weathertight shell reached before the fit-out begins
- Building control inspected at foundation, damp course and steel stages
- Waste cleared as we go, not left piled up outside
Built a new extension at rear of property. Laid foundations, drainage, raised floor, new roof and completed all fixtures and interior decoration…
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…
Giorgio is an excellent and intelligent workman, and with very reasonable prices! He installed a kitchen extractor fan in a complicated situation…
FAQ
Frequently Asked Questions about House Extensions Stratford
Why do house extensions quotes in Stratford vary so much?
Variation in house extensions quotes across Stratford almost always comes from what has been left out. GS Renovation prices structure, trades, approvals and reinstatement after an E15 survey, so the total can look higher than a quote covering half of it. The honest range is £2,000 to £2,800 per m² for a rear extension (indicative), and the width of the opening into the house decides the steel, which a quote without a survey cannot know.
Can I add a rear extension to my terraced house in E15?
Usually yes. A single storey rear extension on a terraced house in E15 often falls under permitted development, though limits on depth and height apply and a full planning application to Newham Council is sometimes needed. Building control approval is always required for the foundations and steel, and a party wall notice, which you serve as building owner, is needed where you build against a neighbour's wall. We confirm the exact position for your address.
When does the steel go in on a Stratford terrace extension?
After the new walls are up and roofed, when the extension is weathertight. The beam that replaces the old rear wall bears on padstones in both old and new masonry, so the new foundations must be designed to take that point load. The old wall is then propped, cut out and the beam inspected by building control before the ceiling is boarded.
What roof suits a single-storey extension on a Stratford terrace house?
A flat roof with a lantern or rooflights keeps the height below the first-floor windows, while a pitched roof suits a narrower infill. Either must meet Part L insulation standards. Rainwater from the new roof needs a downpipe connected to the drains with correct falls under Part H. Glass area and insulation are balanced at design stage.
Can the kitchen move into a new Stratford extension?
Yes, if the drainage works. The sink and dishwasher waste need falls to an existing drain, which may be under the extension footprint. If a manhole falls inside the new room, it is rebuilt or relocated, and building over a public sewer needs the water company's consent. Drain runs are fixed before the slab is poured.
How is the new floor level matched to the house in a Stratford extension?
It is set from the existing floor and the damp-proof course, not guessed. The slab must allow for insulation, screed and any underfloor heating, all within that depth so the finished floor runs through level. A step down is sometimes unavoidable where the existing house floor sits high. Building control checks the damp-proofing before the slab.
Does a sewer behind a Stratford terrace change how an extension is approved?
Yes. In Newham an extension over a sewer needs a full plans application because a building notice is not suitable. Behind a terraced house a shared drain can run under the yard or garden, so a camera survey comes before the footprint is fixed. If the pipe sits under the extension, the drawings show how it is protected or diverted, and the build waits for approval rather than starting two days after a notice.
When does Newham need telling that a Stratford extension has started?
For an extension, Newham must be told when works are deemed commenced, which is when the foundations are constructed and the lowest floor structure is complete. That is a point part way into the job, not the day the digger arrives. We put the notice into the programme at slab stage, alongside the foundation and drainage inspections, so the milestone is recorded without anyone having to remember it.
Can a garden tree block a Stratford extension in a conservation area?
It can shape it. In a Newham conservation area every tree is protected once its stem is more than 7.5cm wide and it stands more than 1.5 metres high. Foundations near a protected tree need a design that limits root damage, and removing one to make room is not automatic. We measure every tree near the footprint at survey and raise any that meet the test with Newham Council before the design is fixed.
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