BasementsSt John’s Wood NW8
Basement conversion in St John’s Wood.
Basements under St John’s Wood villas, within Westminster’s one storey rule. Engineered, monitored and built by one team.
A basement under a villa.
NU Projects is a design and build company in Fulham SW6, founded in 2010. We handle basement conversion and construction in St John’s Wood NW8, under one contract. A basement runs £450 to £500 a sq ft, construction only. Call 020 7731 6841, and a budget estimate typically follows within seven days.
St John’s Wood is villas more than terraces. Many are detached or semi-detached, in stucco or stock brick, with real gardens.
So a basement here can often go wide. The garden, not the party wall, sets the limit.
St John’s Wood sits in the City of Westminster, not Camden. Westminster’s City Plan sets the rules for every basement here.
We design, engineer and build the basement under one contract. Our own quantity surveyor prices it open book.
What the council allows.
- Council
- City of Westminster. Hampstead, to the north, is Camden, with different rules.
- Depth
- City Plan Policy 50. One storey below the lowest original floor. A large site with good access may be allowed more.
- The garden
- It may run under no more than half the garden. An undeveloped margin is kept around the boundary.
- Soil and trees
- At least one metre of soil goes over the basement, plus a drainage layer. Trees may need up to 1.5 metres.
- The application
- A structural methodology statement goes in with it. So does the Code of Construction Practice pro forma.
Source: Westminster’s City Plan, January 2026 edition, Policy 50. Read on 2 October 2026. Policies change, so we read them again for your address.
Basements we have built.
South Kensington·New build
South Kensington new-build houses
Our basement work: two new houses, with a pool two floors below the street.
See the project
Marylebone·Apartment
Marylebone listed apartment
Our work under Westminster’s rules, a Grade II listed apartment in Marylebone.
See the projectCompleted work, photographs
What it costs.
£450 to £500a sq ft, construction only. Our basement band.
£180k to £300kConverting an existing basement. A project total, from our 2026 cost guide.
£500k to £900k+Digging a new basement. A project total, from our 2026 cost guide.
The band is a rate per square foot, construction only.
The cost guide figures are project totals. Fees, party wall costs, contingency and VAT sit outside.
A wide villa garden often allows a bigger single storey. The total rises with the area.
Open the calculatorThe 2026 cost guideBasement costs in full
Basements in St John’s Wood, answered.
Is St John’s Wood in Camden or Westminster?
Westminster. Its basements follow Westminster’s City Plan, Policy 50.
Hampstead, to the north, is Camden, with its own rules.
How big can a basement be under a St John’s Wood house?
One storey below the lowest original floor.
It may run under no more than half the garden. A margin is kept at the boundary.
A large site with good access may be allowed more.
Does a St John’s Wood basement need a structural report?
Yes. A structural methodology statement goes in with the application.
A suitably qualified engineer signs it off.
What does a basement in St John’s Wood cost?
Our basement band is £450 to £500 a sq ft, construction only.
A new dig runs £500k to £900k and more, as a project total.
Related pages.
In St John’s Wood
From the journal358 notes, free to read
St John’s Wood, written up.
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3 min read
Basement waterproofing and pumps in London
What keeps a London basement dry. Waterproofing as one coordinated design, when pumps are needed, alarms, servicing and costs.
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5 min read
The real cost of a London basement: what homeowners need to know before starting
What a London basement actually costs in 2026. Shell against fit out, what sits outside the build rate, fees, contingency and the hidden risks.
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3 min read
Basement extensions in London: what homeowners need to know before they dig
Everything London homeowners need to know about basement extensions. Planning, costs, party walls, and construction advice from NU Projects.
Basements, St John’s Wood
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