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If you are considering a basement conversion Wimbledon or the construction of a new floor beneath your home, Design & Build Wimbledon is a one-stop-shop, specialising in design, high-end build and fit-out services for residential properties located within Wimbledon and the surrounding areas. We are happy to work with your own design team, we are, at your request, more than happy to work alongside them to ensure that your project is completed to your satisfaction. Our family business, which is based in Wimbledon, offers professional consultants, highly skilled architects and engineers, dedicated project managers, site managers and build- teams. All are committed to providing you with innovative ideas and concepts, expert guidance and support, ensuring that you realise the full potential of your property and create your ideal space.

Stunning Basement Conversions Wimbledon

Design & Build Wimbledon completed countless basement conversion projects in Central Wimbledon. Our focus and determination are both solely centred around you, resulting in a completely bespoke and personal service.

We believe true design is about to understand our clients illuminating aspirations, requirements and patterns of habitation.

Basement Conversion

Truly Personal Services, From Start to Finish

We can deliver Design & Build projects in Wimbledon and surrounding areas, projects including loft conversions and kitchen extension. We pride ourselves that our attention to detail is paramount to us. With meticulous precision to ensure that the proposed design satisfies the demanding needs of your style and aspirations.

No matter what we do, we strive to preserve the privacy and security of your home. We complete our job with minimal disruption and ensure to install all needed safety measures to make the process exceptionally stress free.

No Hidden Cost, No Unexpected Expenses

The committed team at Design & Build Wimbledon always completes the job within the pre-scheduled deadline and minimises the unexpected expenses associated with the construction process. Prior to the job, we accurately evaluate the exact requirements of the client, inspect the site appropriately, and prepare an all-inclusive, detailed quote that helps to cut down unanticipated expenses.

Flexibility and Prompt Customer Service

We provide you with an added bonus of a flexible site evaluation and prompt customer service at all times. We endeavour to take the time to listen to your needs and suggest the most viable solution that meets the highest possible standards.

Satisfaction Guaranteed

Our builders are extensively experienced and that’s why we are able to understand the complexities and potential issues that could occur as part of any full house renovation, loft conversion or kitchen extension project. Considering this challenge, we give our customers the convenience to enjoy a 10 year work guarantee on structural projects. Moreover, we provide adequate insurance coverage of up to £5 million.

We cover all clients based in the Wimbledon boroughs of Wimbledon & Chelsea, Hammersmith & Tolworth, Westminster, Camden, Southwark, Lambeth, Wimbledon, Merton, Barnes, Kingston upon Thames and Richmond.

Basement Conversion Wimbledon – Planning restrictions

Every Borough Council / planning office differs in policy regarding what you can and can’t do with basements conversion in you area. It’s crucial that you do due diligence to find out more about the latest basement policy and guidance of your local authority. This is has to be done at the very start so you know what kind of basement is feasible, and all the requirements attached to the application and any design or cost implications.

For example:

Wimbledon Borough Council basement policy states that when considering a lightwell in the front garden “you must ensure that at least 50% of the front garden remains following excavation of a “lightwell”.
Merton basement policy stipulates not to exceed 50% of either the front, rear or side of the garden of the property for constructing a basement.
Royal Borough of Wimbledon & Chelsea basement policy limits the extent of basement excavation to no more than the depth of a single storey.
And Westminster’s new basement policy has introduced a levy from 1 September 2016 for a subterranean squad of “basement nuisance busters’ – charged with overseeing and controlling traffic impact, stricter working hours and complaints. It’s the first of its kind in the country and assumed to be picked up by other boroughs eventually.

Conservation area restrictions for basement conversions in Wimbledon

If this is applicable, you will need to ascertain any additional restrictions placed on a basement conversion in your area.

For those considering a basement under their house in Wimbledon, we recommend you dig deep (4M-4.5M) to get a high ceiling (2.7M to 3M), put in light wells (and roof lights where possible) to get an incredible space that feels just as good, if not better than your accommodation upstairs.

These are some of the rooms and types of accommodation that we see basement conversions result in:

  • cinema room
  • kids playroom
  • games room
  • gym
  • sauna
  • swimming pool
  • spa, massage room
  • sanctuary
  • nanny, granny and teenage flats
  • bowling alley
  • recording studio
  • luxury car park

Who we are

Design & Build Wimbledon offer bespoke Design and Build basement conversion services tailor-made to your personal aspirations, requirements and habitual patterns.

As a team, we have over 20 years of combined experience in modelling, designing and building beautiful homes across Wimbledon.

Our team consists of:

• Project managers

• Pre-contract & contract managers

• Design consultants

• Quantity Surveyors

• Structural Engineers and professional Builders.

The result is a seamless service which allows us to provide a full Design and Build service under one roof.

We are one of the very few firms who choose not to ask for deposits or upfront payments.

Design & Build Basements

Our service is fully comprehensive, covering everything from your initial design ideas briefing, right through to the completion of your project:

We can take care of:

• Architectural Drawings

• Planning applications

• Building Control

• Project cost estimation

• Detailed architectural CAD / 3D designs

We are happy to work on projects across Wimbledon from as little as £50,000 and are able to provide a full service for jobs right up to £3m+.

We ensure that we can take care of all aspects in regards to your projects, including: Basement Conversion, House Extensions, Loft Conversion


We work with RIBA Chartered Architects, and Architectural designers who are able to create and take care all drawings and plans on your behalf, and our high calibre builders who will turn your ideas into a reality, are full-time employed by our firm. This in result will ensure that all building work will be done in-house, which speeds up the whole sequential process.

Industry proven method to achieve minimising the delays between building stages of a project; in fact, through close nit teamwork, some tasks can be overlapped. No need to wait for next stage sign-0ff in order to allow the next task to begin can result in longer delivery of project. This advantage is most keenly felt in the transition between the planning and building phases; using a traditional approach, following the approval of plans, there is often a delay of several days, or maybe weeks, during which quotations are requested and received from building contractors.

We estimate that this reduces the time taken by some projects by up to 40%. Also, having to deal with a single company throughout the whole process is far easier for you, especially if an issue might arise, in which case responsibility cannot be shifted from one party to another.


Once armed with local authority policy, the necessary survey results and an outline budget estimate, you will need to design your basement space plan which will include:

  • How big and what shape it will be
  • How you propose to connect your new basement to your existing house
  • What’s the best space plan and room lay-out
  • A high level interior design plan and furniture lay- out so that you know the architectural design is in perfect harmony with the interior plan
  • Where to put services i.e. drains, electric runs, ventilation, etc.
  • Access and exit points including compliance with building regulations
  • Roof lights and light wells to provide lots of natural light and ensure a high quality living space


Structural design and calculations:

A structural engineer now needs to be appointed to decide and detail the best way to design, support and build your basement shell and core. The ‘shell and core’ is fundamentally the reinforced concrete structure in the ground. The engineer’s design will factor in all survey information available as well as your project timescales and budget constraints. The resulting piece of work is a series of drawings and calculations which identify the construction sequencing, materials, steelwork, under-pinning and/or piling details, party wall detailing and CDM (Construction Design & Management) requirements. The structural design is required before the Party Wall Agreement process starts as any appointed surveyor will want to review these as part of your Award.



By mastering best practices and applying them on every commercial and residential building project regardless of the budget or size, we can ensure lasting quality. We believe luxury home is about having standards and not cutting corners.

Our uncompromising aim is to deliver the highest quality refurbishment projects on brief, on time and within budget. We treat every job as a luxury project, with the same approach and same team of experienced, trained specialists working across our sites. Learn more about our Company.


There is no limit to the type of building project that we can undertake. We can renovate any part of your home, from converting your loft, to excavating your basement. We can also take on any scale of work, whether it be a complete new-build, the addition of an extension, or the renovation, remodelling or refreshing of an existing space.


One of the joys of working with our team of designers is the opportunity for you to witness the way in which we at Design & Build Wimbledon painstakingly realise your design vision. We continually help you to visualise how your project is developing, using computer-generated images, ‘mood boards’ and drawings. We can even show you accurate representations of how your furniture and lighting configurations will look. Needless to say, with our vast experience in the trade, we are able to design your living space in a variety of styles.


The process begins with us helping you to visualise how your renovated home will look, and to imagine how you will live in it. From this initial conversation, we will develop a design brief in the form of a three-dimensional representation of your new living space. This will enable you to finalise your needs and aspirations.


Subsequent design work will produce a more formal specification, embodying the unique details of your specific requirements. You can be sure that this detailed spec will be highly personalised to your needs and aspirations.


The final stage of the process is to finalise decisions as to the materials and finishes that will be used. We can help you to select the look and the textures that blend perfectly with your living space, and we can also advise you on solutions that meet sustainability objectives. We believe that the look of your living space should complement and enhance your lifestyle, and not dominate it.


Basement extension is a great way to gain more functional space and get the maximum benefits from the extension process. At the same time, it is possible to increase the property value, typically by around 20% of its value.

Creating a space underneath your house can be a really cost-demanding process, especially if excavation and damp-proofing is required, as it is more expensive per square meter than a common above-ground extension.

There exist two main ways of using the space under your property and making it a habitable environment:

  • Renovation of existing basement or cellar;
  • New basement construction underneath the house.

Each of these cases has its peculiarities which influence the costs significantly. Let’s consider all the factors in detail, so that you can avoid surprising and unpleasant situations once the process has already started.
Conversion of an existing cellar is not as expensive and may cost approx. £750 – £1,400 per square metre. It is necessary to take into consideration the features of the existing structure of the basement, the number of walls which will be built, individual installations and flooring design.

Factors that may increase costs include moving services, especially in the case of poor access to the site, underpinning of the existing structures if necessary, water-proofing, etc.
As for the new basement construction, costs may can vary significantly and usually include the following constituents (approximate costs per square metre):

  • Planning and Building regulations applications (£750 – £1200)
  • Party wall agreement (£700 per each neighbour)
  • Engineer fees (£1000 – £1500)
  • Floor level lowering and cellar underpinning(£1500 – £2000)
  • New basement space excavation (£1500 – £3000)
  • Lightwell and external access construction (£5000 – £7000)
  • VAT contractors additional fees may reach up to 20%.

To sum up, a shell place construction will cost £1,920-£2,640 per square metre. If you have an already existing cellar, converting it will cost £720-£1,800 per square metre.

All the above listed figures are approximations and may vary considerably depending on a number of factors. Moreover, they don’t take into account the design and interior or exterior finishes: wall painting, furniture, flooring, additional fittings or any other decorating ideas.

Design & Build Wimbledon always adjusts the costs to the customer’s budget capabilities, without lowering the standards and quality of our work.


Net Promoter

This is a measure of both the loyalty of our customers and the likelihood of them recommending us to others.

Client Retention

This is a measure of how many of our customers come back and use our services again.


This expresses the proportion of our business that results from referrals from previous clients.

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