BasementsKensington W8
Basement construction in Kensington.
Basements under Kensington terraces and villas, within the borough’s one storey rule. Engineered, monitored and built by one team.
Basements under the one storey rule.
NU Projects is a design and build company in Fulham SW6, founded in 2010. We handle basement conversion and construction in Kensington W8, 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.
Kensington runs from stucco terraces to brick villas on the hill. Many houses are split into garden flats.
Many terraces back onto communal gardens, so the house’s own garden is often small.
Kensington and Chelsea was the first council to limit how far basements go. Policy CL7 sets one storey, under half the garden.
Every Kensington basement now needs planning. We prepare the application, the structure and the traffic plan together.
What the council allows.
- Council
- Royal Borough of Kensington and Chelsea, which covers all of Kensington.
- Extent
- CL7, adopted January 2015, was the first policy to limit basement extent. One storey, under half the garden.
- Later changes
- Under the 2016 Basements SPD, the storey cannot be split into two floors later.
- Planning
- An Article 4 direction since April 2016 means every basement needs planning.
- On site
- A Construction Traffic Management Plan goes in with the application. The Code of Construction Practice, revised 2019, governs the site.
Source: Policy CL7, the 2016 Basements SPD and the Article 4 direction. Read on 6 September 2026. Policies change, so we read them again for your address.
Dug and built in the borough.
South Kensington·New build
South Kensington new-build houses
Our dig for two new houses in the same borough, three floors down.
See the project
Chelsea·Townhouse
Chelsea basement and extension
A new basement and kitchen extension in Chelsea, in the same borough.
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 whole project totals, before fees, contingency and VAT.
A garden flat, a terrace and a villa each price differently. So we price the house itself.
Open the calculatorThe 2026 cost guideBasement costs in full
Basements in Kensington, answered.
Can I dig a basement under a Kensington garden flat?
Sometimes, if the flat owns its garden and the freeholder agrees.
The lease usually needs a licence for structural work.
CL7 still applies, one storey under half the garden.
Why did Kensington and Chelsea limit basements?
The council wanted to limit the disruption of large basement digs.
It adopted CL7 in January 2015 to limit their extent.
Can I extend an existing cellar in Kensington?
Yes, within CL7. The rules cover extensions to existing basements too.
Lowering an existing cellar is often the simplest route.
We survey it first and test the depth against the policy.
What does a Kensington basement 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.
A conversion of an existing basement runs £180k to £300k.
From the journal358 notes, free to read
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Basements, Kensington
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