Basement gyms in South West London.
Chelsea · SW3 · Chelsea townhouse, opened up and fitted outCase study
A gym below the house, with room to lift and air to breathe. We plan the floor, the height and the cooling together.
Room to train under an SW house.
- Clear height
- Planned into the single storey
- Strong floor
- Reinforced slab under resilient rubber
- Cool air
- Ducted in, with the heat taken away
NU Projects is a design and build company in Fulham SW6, founded in 2010. We handle basement gyms and spa rooms in South West London SW. A new basement dig typically runs £500k to £900k. Converting an existing basement runs £180k to £300k. Call 020 7731 6841, and a budget estimate typically follows within seven days.
Above ground, SW houses rarely have a spare room for training. Below ground, a gym can take a whole bay of the basement. Noise and weights stay away from the bedrooms.
Height is the first test. One storey must hold the slab, floor layers, ducts and room to lift overhead. We fix those levels before the dig.
A gym gets hot quickly with no window to open. Cooled fresh air arrives through quiet ducts. A steam room and a gym can share one plant room.
We fitted a mirrored basement gym under a Chelsea townhouse. It holds a spin bike and a rowing machine between lit pilasters.
How the borough judges a basement gym.
- Council
- Royal Borough of Kensington and Chelsea, whose Local Plan dates from 2024.
- Ceiling height
- Policy CD11 gives one storey. Rubber, slab and ducts must leave room for overhead lifts.
- Pool allowance
- The SPD gives a pool a little extra depth. A gym on its own gets none.
- Consent
- Planning permission is needed. The gym, sauna and plant are drawn into one application.
- Floor
- A reinforced slab, with rubber over a resilient layer.
- Plant
- Gym cooling and steam share one plant room.
Source: Kensington and Chelsea’s Local Plan 2024, Policies CD4, CD5, CD11 and CD13. Read on 3 October 2026. Policies change, so we read them again for your address.
Gyms and steam rooms in South West London.
Chelsea·Townhouse
Chelsea townhouse, opened up and fitted out
A mirrored basement gym in a Chelsea townhouse, SW3.
See the project
Kensington·New build
Kensington new-build houses
A steam room and walnut joinery on a lower leisure floor in Kensington.
See the projectCase study
What a basement gym costs in South West London.
£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.
Most SW gyms sit within a larger basement, priced as one.
Both are project totals, before fees, party wall costs and VAT.
What South West London owners ask about gyms.
In South West London
- Every service in Chelsea
- Basement construction in South West London
- Basement swimming pools in South West London
- Basement golf simulator rooms in South West London
- Design and build in South West London
Gyms nearby
- Basement gyms across London
- Basement gyms in Chelsea
- Basement gyms in Kensington
- Basement gyms in South Kensington
- Basement gyms in Holland Park
- Basement gyms in Notting Hill
- Basement gyms in Knightsbridge
- Basement gyms in Belgravia
- Basement gyms in Mayfair
- Basement gyms in St John’s Wood
- Basement gyms in Hampstead
- Basement gyms in Fulham
- Basement gyms in Weybridge
- Basement gyms in Cobham
- Basement gyms in Oxshott
- Basement gyms in Marylebone
- Basement gyms in Highgate
- Basement gyms in Primrose Hill
- Basement gyms in Earl’s Court
- Basement gyms in Pimlico
- Basement gyms in Westminster
- Basement gyms in West London
- Basement gyms in North London
- Basement gyms in South London
- Chelsea
- Fulham
- South Kensington
- Belgravia
Further reading, from the blog
What clear height suits a gym beneath an SW terrace?
Enough for overhead lifts under the finished ceiling.
We set the levels before the dig begins.
Will dropped weights disturb the rest of the house?
A reinforced slab and resilient layer absorb most of the impact.
Rubber flooring sits on top.
Can a basement gym get extra depth, like a pool?
Not in Kensington and Chelsea.
The 2016 SPD gives extra depth to pools, not gyms.
Can a steam room sit beside the gym?
Yes. Both can share one plant room.
We plan them in the same drawings.
See it builtNear South West London
See it built.
Finished homes, designed, priced and built by NU.
Chelsea · SW3 Townhouse
Chelsea basement and extension
A new basement, a kitchen extension and a full interior renovation.
Case study
Fulham · SW6 New build
Fulham, four new-build houses with basements
Four architect designed houses, each with a basement, built as a joint venture.
Case study
Fulham · SW6 Basements
Fulham basements
Basements we have dug and built under Fulham houses, close to our studio.
Case study
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