Basement Extensions

Basement conversions can be used for anything a client desires, from extra bedrooms, gyms as well as playrooms, wine cellars, swimming pools and cinemas.

Basement Extensions

The last 15 years have seen Londoners excavating underneath their properties in an effort to create and design all kinds of exciting extensions. Many of the capital’s most exclusive residential addresses now have almost as much space below ground as above. Basement excavations have proved particularly popular for London mews houses, these subterranean rooms are an excellent way of limiting the visual impact on a property as these properties are often located in conservation areas and therefore bound by strict planning rules. A basic basement extension could increase the floor area of a two-storey property by over half but many Londoners are now opting to submerge multiple floors underground with average extensions now measuring up to 700sq ft.

Basement architectural design detail and bespoke features maximise light and volume through the building to open up the space, improving the traditional dingy feel of a basement conversion with an added advantage of a basement room being accessible from the ground floor.

Each borough in London has its own set of planning guidelines and complexities surrounding the design and construction of basement conversions. It is therefore important to appoint an architectural team, who are able to guide you through this process effectively, resulting in a design and set of plans that will pass through planning permission. At RBD Architecture & Interiors we have an experienced architectural team to guide our clients through the architectural and planning permission side, right through to construction of the basement.

Basement conversions can be used for anything a client desires, from extra bedrooms, gyms as well as playrooms, wine cellars, swimming pools and cinemas.

Please take a look at some of our recently completed basement properties we have designed, extended and refurnished in the most sought-after areas of London.

If you own or are thinking about buying a house in need of renovation or extension please call us for a chat on : + 44(0)207 193 7245

View our basement extension projects.

Our Service

We offer a full residential architectural and interior design service that enables us to create and manage your scheme from initial concept to fully costed design. Our in-house London residential architects and design team tailor the design to suit your style and budget and have the experience and knowledge to successfully navigate the pitfalls of individual boroughs planning departments.

Our Approach

Our firm specialises in award- wining residential design, our unique approach has enabled us to achieve commissions on a broad range of residential projects from new-build architecture, renovation, mews house architecture, restoration to apartment refurbishments. We are focused on creating designs are not only livable and elegant, but also designed intelligently, efficiently and with the owners needs in mind.


We build strong, trusted relationships with our residential clients through honest, professional, budget-conscious build solutions. The quality of our residential architecture in London speaks for itself – and this is perhaps why we receive an extremely high proportion of repeat business and word-of-mouth recommendations.

RIBA & SBID Members

As members if the RIBA (Royal Institute of British Architects) and SBID we offer an in-house interior design consultancy service. Our unique approach means clients are presented with a cohesive scheme that sensitively translates their lifestyle and seamlessly integrates with, and alongside, our London residential architecture design service.

Residential Architects London


Start your project

If you are thinking of adding a basement extension or making internal alterations to an existing home, we can help you maximise your project’s potential, research its planning history and advise on any limitations.

Get in touch today with our Residential Architects to discuss your project.

Residential Architecture London

Client Testimonials

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