Single-storey basement extensions to South Hampstead villas — designed within Camden’s strict basement policy, with the Basement Impact Assessment, underpinning and waterproofing in-house.
Speak to the studio directly: 020 8054 8756
A basement extension adds a full new floor without changing the look of the villa from the street — one of the most effective ways to gain serious space in South Hampstead’s protected conservation streets. Done properly it gives a light, dry, fully tanked room for a kitchen, media room, gym or guest suite.
Camden operates one of the strictest basement policies in London. New basements are generally limited to a single storey, must not extend under more than half of the garden, and require a Basement Impact Assessment prepared by a chartered engineer covering structure, ground stability and groundwater, alongside a construction method statement — with the close-set villas and garden trees adding further sensitivity.
We design within that policy from the outset, because a non-compliant scheme is simply refused. Engineering, underpinning, waterproofing and the planning case all sit in one design-and-build contract with a single point of responsibility, and honest budgets in pounds sterling.
In South Hampstead, Camden’s basement policy and the close-set villas set what is buildable.
Camden policy generally limits a new basement to one storey under the house and part of the garden.
A BIA by a chartered engineer covering structure, ground movement and groundwater is required; we commission it.
No more than half the garden, and mature garden trees add sensitivity to the design.
A construction method statement and traffic management govern the work on a tight site.
From feasibility against Camden policy to a dry, finished basement — all in-house.
Testing the site against Camden’s basement policy before any design work begins.
Commissioning the Basement Impact Assessment, structural method and traffic plan.
Drawings and a Camden planning case for a compliant single-storey basement.
Sequential, engineer-designed underpinning to form the new depth safely.
Retaining structure, propping and party wall awards with neighbours.
Type C cavity-drain or tanked systems with pumps and a maintainable design.
Lightwells, sun-pipes and mechanical ventilation to make the room usable.
Kitchen, gym, media or guest-suite fit-out, snagging and handover.
We design and build single-storey basements within Camden policy across South Hampstead’s villas in NW6.
South Hampstead sits within the London Borough of Camden — see our South Hampstead area page and North London refurbishment overview.
Book a no-obligation consultation at our North London studio on Finchley Road, in Hampstead, or at your property. We will give you an honest read on approvals, programme and budget band — in pounds sterling — before you commit.
Site visit · approvals read · outline budget band (GBP) · programme indication. No obligation.
Send Project DetailsThe same NW3 design-build team covers the neighbouring areas: