Basement gyms in Knightsbridge.
Chelsea · SW3 · Chelsea townhouse, opened up and fitted outCompleted work, photograph
A gym below a Knightsbridge townhouse or mews, often beside a pool. One team handles both councils’ rules.
What a Knightsbridge gym has to solve.
- Two councils
- The borough line runs through the area
- Three homes
- Completed here, one with a pool
- SW1X · SW7
- Townhouses and mews houses
NU Projects is a design and build company in Fulham SW6, founded in 2010. We handle basement gyms and spa rooms in Knightsbridge SW1X, under one contract. A basement runs £450 to £780 a sq ft, construction only. Call 020 7731 6841, and a budget estimate typically follows within seven days.
Most Knightsbridge homes are mansion block apartments. Basements happen in the townhouses and mews houses. These owners often want a gym, a spa and a pool together. The lower floor is the only place to put them.
Both councils now allow one storey below the house. Their details differ, so the address decides the route. Listed houses face tighter limits on either side of the line. We settle the council before we sketch a room.
A pool and a gym share a floor but not an atmosphere. Humid pool air will rust a rack. So the gym is separated by a sealed lobby, with its own air supply. The hall for the pool gets the dehumidifier.
We completed a Knightsbridge townhouse with a pool and a wine room. The gym follows the same logic of separate wet and dry zones. One team designs, prices and builds the lot.
What the council allows in Knightsbridge.
- Council
- Two councils meet here. Kensington and Chelsea lies west and south, Westminster east.
- Kensington side
- CD11 allows one storey under half the garden. A gym and pool share it.
- Westminster side
- Policy 50 allows one storey under the lowest original floor. Small gardens may extend four metres.
- Listed houses
- Kensington and Chelsea resists digging under a listed house. Westminster guards the room order.
- Humidity
- A gym beside a pool needs its own air supply.
Source: Kensington and Chelsea’s Local Plan 2024 Policy CD11, and Westminster’s City Plan Policy 50. Read on 3 October 2026. Policies change, so we read them again for your address.
Pools and gyms in the area.
Chelsea·Townhouse
Chelsea townhouse, opened up and fitted out
A basement gym in a Chelsea townhouse, close by.
See the project
Knightsbridge·Townhouse
Knightsbridge townhouse, pool and wine room
The pool in a Knightsbridge townhouse we built. A gym would sit apart from it.
See the projectCompleted work, photographs
What a basement gym costs in Knightsbridge.
£450 to £780a 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.
These are two kinds of figure. The band is a rate per square foot, construction only.
The cost guide figures are whole project totals.
Fees, party wall costs, contingency and VAT sit outside them.
What Knightsbridge owners ask about gyms.
In Knightsbridge
- Every service in Knightsbridge
- Luxury refurbishment in Knightsbridge
- Basement construction in Knightsbridge
- Interior design in Knightsbridge
- Party wall surveying in Knightsbridge
- Basement swimming pools in Knightsbridge
- Basement cinema rooms in Knightsbridge
- Basement golf simulator rooms in Knightsbridge
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 Belgravia
- Basement gyms in Mayfair
- Basement gyms in St John’s Wood
- Basement gyms in Hampstead
- Basement gyms in Fulham
- Belgravia
- South Kensington
- Chelsea
- Mayfair
Further reading, from the journal
Can a Knightsbridge basement gym sit next to a pool?
Yes, with a sealed lobby between them.
The gym has its own air supply.
The pool hall keeps its dehumidifier.
Which council covers my Knightsbridge basement gym?
It depends on the address.
The line between the two councils runs through Knightsbridge.
We check the house before we advise.
Can a Knightsbridge mews house have a basement gym?
Often yes, on the Kensington and Chelsea side.
Westminster protects the original order of rooms in listed houses.
We read both rules for your mews.
Will pool humidity damage a Knightsbridge basement gym?
Not if the two are separated.
Equipment stays dry behind the sealed lobby.
Humid air is kept in the pool hall.
What does a Knightsbridge basement gym cost?
Our basement band is £450 to £780 a sq ft, construction only.
We price the house itself.
Tell us about your home in Knightsbridge.
Your name and one way to reply are enough. It goes straight to the studio.
- Already have an architect or designer? We build to their design. Working with your designer
- An NDA on request, and your home is never published without your consent. How we work in confidence