House Extensions Pimlico
Single storey rear and double storey extensions in Pimlico, 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 Pimlico, from the stucco terraces near the river to the garden-square houses of SW1. We handle groundworks, steel, roofing and full fit-out, and we tell you clearly whether your project is permitted development or needs a planning application.
In Pimlico, 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 Pimlico: 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.
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Pimlico range: choose above
Rear and side-return extensions in Pimlico
Pimlico's stucco terraces usually have narrow rear yards, so the most practical additions are rear and side-return extensions that square off the ground floor and open the house to its garden. We dig and pour foundations to suit the ground conditions, install the steel beams that carry the existing rear wall and tie the new roof cleanly into the period elevation behind.
Because so much of Pimlico is white-stucco and sits within a Westminster conservation area, external changes are scrutinised closely, and listed buildings need listed building consent for alterations. We advise honestly on what is achievable at the rear, keep new work sympathetic to the original brick and render, and manage the full build so kitchens, glazing and finishes all come together under one team.
Housing in Pimlico
About 10,180 homes are listed for Pimlico, and the mix is 6% houses to 94% flats, with 34% built after 1945, 10% in 1919 to 1939 and 55% earlier. Most homes here are flats, and a flat in Pimlico has no householder permitted development rights, so extending one needs planning permission and the freeholder's consent.
Extending a Pimlico terraced house under Westminster's conservation guidance
Only 6% of Pimlico homes are terraced houses, and an extension to one is read against Westminster's guidance on development and demolition in conservation areas. That guidance asks for an addition that is architecturally subordinate to the house and in keeping with its scale and proportions. It treats full width additions at the rear as generally unacceptable, with certain exceptions where the extra space is at basement level. For a stucco terrace with a narrow rear yard, the guidance points towards a part-width addition that leaves some of the original back wall visible, or space below ground under Westminster's separate basement policy.
The Pimlico Neighbourhood Plan was adopted on 7 December 2022 and forms part of Westminster's Development Plan, so a Pimlico application has to answer its policies as well as the City Plan. For an unlisted house, Westminster's householder pre-application advice is written only, with no meeting, and comes back on a 28 day timescale. Asking for it before your architect settles the scheme lets the officer's comments shape the drawings. The build programme then starts from a design with a realistic prospect of approval, rather than one likely to be redrawn after a refusal.
Planning and party walls for Pimlico extensions
Whether your Pimlico extension is permitted development or needs full planning permission depends entirely on the property. Most Pimlico homes are flats, which have no permitted development. For a house, the Pimlico Conservation Area removes permitted development for side, two-storey and roof extensions, though a single-storey rear extension within the limits can still qualify unless an Article 4 direction removes it, and a listed house needs listed building consent as well. So many SW1 extensions require an application to Westminster City Council rather than proceeding automatically. We assess your specific house first, then set realistic expectations before any design work begins so there are no surprises at submission.
Extensions here almost always touch a shared boundary, which brings the Party Wall etc. Act into play alongside the building regulations that govern the structure itself. You serve the right notices as building owner, using the drawings we supply. We coordinate the engineer's steel design and arrange building control inspections at foundation, structure and completion. Keeping planning, party wall and building regs on separate but parallel tracks is how we keep a Pimlico extension moving without costly stops.
Kitchen extensions in Pimlico
94% of homes in Pimlico are flats, and a flat has no householder permitted development, so a ground-floor flat's kitchen extension needs planning permission from Westminster City Council and the freeholder's consent. With so few houses here, the realistic kitchen gain in most Pimlico homes is a better layout inside the flat rather than an extension. The fit-out is priced on its own page, kitchen renovation in Pimlico; the build figures are in the table above. Double storey extensions belong to the few houses here.
- Single and double storey extensions
- Drainage diversion and build-over agreements with the water authority
- Wrap-around extensions and infills
VOA Council Tax stock of properties, March 2025, for Pimlico North and Pimlico South. Counts rounded by the VOA.
Why Choose GS Renovation in Pimlico
Extending a period home in SW1 involves conservation constraints, shared walls and close neighbours, so experience matters. GS Renovation manages the whole project, from foundations and steel to roofing and fit-out, and guides you honestly through permitted development versus a Westminster planning application. With our founder's 30+ years on the tools, we deliver an extension that suits the house and satisfies both planning and building control.
- Site left safe and secure at the end of every day
- Foundation depth set after trial holes, drains and trees are checked
- Weathertight shell reached before the fit-out begins
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…
George was brilliant. Lovely bloke, very reasonably priced and a perfectionist to boot. He completed our small kitchen renovation with care and great…
FAQ
Frequently Asked Questions about House Extensions Pimlico
How much should house extensions in Pimlico cost?
The cost of house extensions in Pimlico is typically £2,000 to £2,800 per m² for a rear extension (indicative), and the SW1 survey decides where in that range your job lands. The biggest mover is what the survey finds: the depth of neighbouring Pimlico foundations decides how deep the new footings go. GS Renovation shows the Westminster City Council building control fee on its own line, and the written figure follows within days of the visit.
Will my Pimlico extension need planning permission or is it permitted development?
Most Pimlico homes are flats, which have no permitted development rights. For a house, the conservation area removes permitted development for side, two-storey and roof extensions, though a single-storey rear extension can still qualify unless an Article 4 direction removes it, and a listed house needs listed building consent as well, so many projects need a planning application to Westminster City Council. We assess your house before designing anything and tell you plainly which route applies, then handle the building regulations that run alongside it.
Can a lower ground floor flat in Pimlico be extended?
Occasionally, but not through permitted development, which applies to houses and not flats. With 94% of Pimlico homes being flats, the rear yard usually belongs to the freeholder, so their consent comes before a planning application to Westminster City Council. A listed building also needs listed building consent. Building regulations apply to any extension that proceeds.
What happens to the drainage when a rear Pimlico extension covers the yard?
It is usually surveyed first, because the yard often holds the building's gullies and drain runs. A private run can usually be diverted beneath the new slab with a rodding point kept, laid to Part H gradients. A public sewer is another matter: the water company has to agree in writing, and Westminster building control will wait for that. On a narrow rear plot, the drain route can fix where the walls can go.
Does digging foundations for a Pimlico extension need party wall notice?
Very likely. Pimlico's rear yards are narrow, and a footing trench there tends to fall within 3 metres of the house next door and below its shallow period foundations, which brings a one month notice under the Party Wall etc. Act 1996. Terraces mean an owner on each side may be served. Dissent from either passes the question to surveyors, whose award comes before excavation.
How does a new Pimlico extension meet insulation rules without spoiling the period rear?
By treating the new part and the old part differently. The extension itself must meet current Part L standards for walls, floor, roof and glazing, while the period rear wall is left as it is where it stays outside the extension. Slimmer, high performing glazing and a well insulated flat roof let the new work sit quietly against the old brick.
Is a Pimlico extension liable for the Community Infrastructure Levy?
Not unless it is large or creates a separate home. Westminster levies CIL by the square metre on every new dwelling, and on development that adds more than 100 square metres of internal floor area through an extension. A modest rear addition to a Pimlico house will fall short of that, but one that also adds a storey below ground could cross it. A homeowner extending their own house can apply for exemption under the national CIL rules, and the exemption is lost if work begins before it is claimed.
Could a Pimlico house be in one of the conservation areas with extra planning controls?
Check before designing anything external. In any conservation area a house loses permitted development for side extensions, rear extensions over one storey, roof extensions and cladding, while a single-storey rear extension keeps it. Westminster has also removed permitted development rights in eight conservation areas, where planning permission is required for the specified minor alterations. The Pimlico Conservation Area was first designated in 1968, so ask Westminster whether it is among the eight. A flat has no householder permitted development in any case.
Why is a Pimlico extension at basement level treated differently from one above ground?
Because Westminster's conservation guidance, while ruling out most full width rear additions, allows certain exceptions at basement level. Anything below ground then falls under the Basement Development Article 4 Direction, which has removed permitted development rights for basements across Westminster since 31 July 2016. The trade for a Pimlico owner is a less visible extension in return for a planning application and a heavier structural process.
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