House Extensions Acton
Single storey rear and double storey extensions in Acton, 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 across Acton and W3, where most homes are flats and the houses range from Victorian and Edwardian terraces to interwar semis. We handle everything from foundations and steel to the final fit-out, on single storey, double storey, side-return and wrap-around projects.
In Acton, 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 Acton: 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 Acton
Acton range: choose above
Side-return and rear extensions in Acton
On the Victorian and Edwardian terraces of Acton's older streets, the classic project is a kitchen extension that fills in the side return, the alley beside the rear closet wing, to widen a galley kitchen into a bright open-plan kitchen-diner. We dig and lay the foundations, build up in matching brick, install the steel beams that carry the original rear wall, and tie the new roof into the existing terrace so it looks like it always belonged there.
Wrap-around extensions combine the side return with a rear projection to make the most of the plot, while double-storey schemes add a bedroom above. On these solid-walled W3 terraces we pay close attention to damp-proofing, ground levels and how the new structure meets the period brickwork, so the addition performs as well as it looks.
Housing in Acton
On the valuation list Acton counts about 25,660 homes, 77% flats and 23% houses; 29% predate 1919, 17% are interwar and 55% post-war. Where most homes are flats, a flat in Acton has no householder permitted development rights, so extending one needs planning permission and the freeholder's consent.
Extending one of Acton's houses within SPD 4 and the inspection sequence
In Acton only 23% of homes are houses. Flats have no permitted development rights to extend, so a ground floor flat extension needs planning permission as well as the freeholder's consent. For the houses, Ealing's SPD 4 Residential Extensions says that in most cases a single-storey rear extension with a maximum depth of 3 metres and a maximum height of 3 metres will be acceptable. Use that as the first test of any design. A scheme beyond it is not ruled out, but it needs a case made for its effect on the neighbours, and that case costs drawings and weeks.
Once the design is settled, the build follows Ealing's typical inspection service plan for a single-storey extension: commencement and excavations first, then DPC, floor damp-proof membranes and floor insulation. Each stage is buried by the next, so the Acton programme is set around those visits. The trenches are seen before concrete is poured, the brickwork is seen at DPC before the slab goes down, and the membrane and insulation are seen before the screed. Keeping to that order means nothing has to be dug out again later.
Planning and party walls in Ealing borough
Whether your Acton extension is permitted development or needs a full planning application depends on the property. Many single-storey rear and side-return extensions fall under permitted development, but corner plots, larger footprints, and any home in a conservation area or with an Article 4 direction may need permission from Ealing Council. We assess your specific house before any drawings are finalised.
Extending up to or across a boundary on a terraced W3 street almost always engages the Party Wall Act, since your neighbours share the flank wall. You serve those notices as building owner, and we give you the drawings and programme they need alongside the building regulations approval that the foundations, steel and drainage all require. The structural sign-off and the planning route are two separate things, and we keep both on track.
Kitchen extensions in Acton
77% of homes in Acton are flats, and a flat has no householder permitted development, so a ground-floor flat's kitchen extension needs planning permission from Ealing Council and the freeholder's consent. Most kitchen extensions here are on the 23% of homes that are houses. The fit-out is priced on its own page, kitchen renovation in Acton; the build figures are in the table above.
Double storey extensions in Acton
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 Acton often needs planning permission from Ealing Council. It is a job for the 23% of homes that are houses; a flat cannot add a storey this way. Ealing Council's Acton conservation areas are Acton Green, Acton Park, Acton Town Centre, Bedford Park and Mill Hill Park (council source). Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.
- Trial holes to set foundation depth near drains and trees
- Steel goalpost frames where the rear wall opens up
- Brickwork and mortar matched to the existing elevation
VOA Council Tax stock of properties, March 2025, for all 5 statistical areas in Acton. Counts rounded by the VOA.
Why Acton Homeowners Choose GS Renovation
Acton homeowners choose GS Renovation because one team carries the extension from foundations to final coat. We advise honestly on whether your project is permitted development or needs planning, plan the programme around the party wall notices you serve where a wall is shared, and build to building regulations throughout. Our founder's 30+ years on the tools mean no surprises on a W3 plot.
- Building control inspected at foundation, damp course and steel stages
- Garden levels and access made good where the build meets outside
- Itemised pricing, so you can see what every stage costs
Built a new extension at rear of property. Laid foundations, drainage, raised floor, new roof and completed all fixtures and interior decoration…
George always kept to commitments and arrived on time. He offered helpful suggestions during his initial visit and promptly provided a reasonably…
The kitchen has been fitted to the high standard. Saaid was polite, professional, tidy, he pays attention to a little details that make huge…
FAQ
Frequently Asked Questions about House Extensions Acton
What happens to the house extensions price if the scope changes in Acton?
Changing the scope of house extensions in Acton produces a written variation before anything else happens, priced against the original figure within £2,000 to £2,800 per m² for a rear extension (indicative). The commonest cause is upgrading a finish once the W3 space is open, which is simple to cost. A layout change is different, because the depth of neighbouring Acton foundations decides how deep the new footings go. GS Renovation rebooks Ealing Council building control inspections where needed.
Will my Acton side-return extension need planning permission?
Often not. Many single-storey side-return and rear extensions in Acton qualify as permitted development, so no planning application is needed, though building regulations approval still applies to the foundations, steel and drainage. But conservation areas, Article 4 directions and larger schemes can require permission from Ealing Council. We check your specific W3 property before committing to a design, so you know the route from the start. A listed building is the exception: work that affects its character, inside or out, including an extension or taking out a wall or chimney breast, needs listed building consent from Ealing Council, and doing it without consent is a criminal offence.
How far can an Acton house extend at the rear without planning?
Up to 3 metres on an attached house, or 4 metres if detached, under permitted development, with more possible through prior approval. These rights apply to houses only, not flats. A conservation area or Article 4 direction can remove them, so check the address with Ealing Council. Building regulations always apply.
Can an Acton flat be extended?
Only through a full planning application, because permitted development does not cover flats or maisonettes. You also need the freeholder's consent under the lease and Building Regulations approval. With flats making up 77% of Acton homes on VOA figures, this route applies to many owners.
How is the roof of an Acton side-return extension tied into the house?
Where the infill meets the closet wing and the neighbour's wall, flashings and the new roof are detailed so rain drains away rather than into the join. Rooflights over the infill bring light to the middle of the house. Insulation must meet Part L, and building control inspects it.
How are drains dealt with under an Acton extension?
They are traced first. If a shared or public sewer runs under the new footprint, building over or near it needs Thames Water's consent, which can shift foundations. Private drains are rerouted to the falls Part H requires, and inspection chambers are moved or sealed. Building control checks them before backfilling.
Which Acton conservation areas change the planning route for an extension?
Five of them. Ealing Council's Acton conservation areas are Acton Green, Acton Park, Acton Town Centre, Bedford Park and Mill Hill Park, and in conservation areas normal permitted development rights are restricted. There a side extension, or a rear extension of two storeys, needs planning permission. In Bedford Park the Article 4 direction also brings a single-storey rear extension under planning. Check the address against the council's maps before a designer is paid.
What happens if a public sewer runs near the back of an Acton house?
The building control route changes. In Ealing a building notice cannot be used where an extension is over or within 3.0m of a public sewer, as shown on the Thames Water Authority map of sewers. That means a full plan application with drawings approved before work. Order the sewer records and a camera survey of the drains before the footprint is fixed, as moving the extension slightly can sometimes keep it outside that distance.
Does the size of an Acton extension change its building control charge?
Yes. Ealing's domestic building control charges set one charge for an extension of less than 40m2 and a higher one for an extension between 40m2 and 60m2. Any development including a basement extension is quoted on request. If the design is near the boundary between those bands, ask the designer for the measured floor area before applying, so the charge and the drawings match from the start.
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