Basement gyms in Hampstead.
Chelsea · SW3 · Chelsea townhouse, opened up and fitted outCompleted work, photograph
A gym below a Hampstead house on the hill, designed around the groundwater report. Camden sets one storey.
What a Hampstead gym has to solve.
- NW3
- A hill of springs and clay
- Audited report
- A Basement Impact Assessment, checked independently
- Burland 1
- The cap on neighbour damage
NU Projects is a design and build company in Fulham SW6, founded in 2010. We handle basement gyms and spa rooms in Hampstead NW3, 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.
Hampstead sits on a hill, with springs and clay beneath it. Gardens slope, and water moves under them. A gym here is built into wet ground.
Camden asks for a Basement Impact Assessment before it decides. An independent auditor checks it at the applicant’s cost. Policy A5 allows one storey and never under an existing basement. The gym is shaped by that report, not the other way round.
Clay swells and shrinks, and water pushes up. A heavy gym floor can sit on a raft that resists both. Damp from the ground is stopped with a drained cavity. Sauna heat adds humidity, so extract is sized to match.
We dug and waterproofed basements under Fulham houses. A Knightsbridge townhouse of ours holds a pool in marble. One team commissions the ground work first, then designs, prices and builds.
What the council allows in Hampstead.
- Council
- London Borough of Camden, under its 2017 Local Plan. The hill adds its own tests.
- Ceiling
- Policy A5 gives one storey. A gym there cannot sit beneath an existing basement.
- Report
- An audited Basement Impact Assessment comes first. It sets the slab, the pumps and the layout.
- Neighbours
- Damage next door is capped at Burland category 1. The build is closely monitored.
- Hampstead plan
- Adopted July 2025. It adds tests on groundwater and trees that a gym must also pass.
Source: Camden Local Plan 2017, Camden’s Basements guidance 2021, and the Hampstead plan 2025. Read on 5 October 2026. Policies change, so we read them again for your address.
What a basement gym costs in Hampstead.
£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 Hampstead owners ask about gyms.
In Hampstead
- Every service in Hampstead and St John’s Wood
- Basement construction in Hampstead
- Luxury refurbishment in Hampstead
- Basement swimming pools in Hampstead
- Basement cinema rooms in Hampstead
- Basement golf simulator rooms in Hampstead
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 Fulham
- Islington, Highgate and Primrose Hill
- Marylebone, Bayswater and Maida Vale
- Kensington
Further reading, from the journal
Why does a Hampstead basement gym start with a report?
Camden decides on the Basement Impact Assessment.
It covers groundwater, drainage and the structure next door.
We commission it before any layout.
Can a Hampstead basement gym go under an existing cellar?
No.
Policy A5 does not allow a basement under an existing one.
The gym must fit a new single storey.
Will groundwater affect a Hampstead basement gym?
It can, as the hill has springs.
The raft, the cavity drain and the pumps are designed for it.
Equipment stays dry.
How is a sauna added to a Hampstead basement gym?
As a lined room beside the gym.
Extract is sized for the extra humidity.
The hill’s damp is dealt with separately.
What does a Hampstead 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 Hampstead.
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
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