As one of the more substantial home renovation projects available, basement conversions are typically both time-intensive and a significant investment. However, when executed correctly, they can dramatically enhance both the usability and value of your property.
Basements offer exceptional versatility and can be adapted to suit a wide range of purposes, including home gyms, cinema rooms, kitchens, entertainment spaces, or additional bedrooms. Once considered a luxury reserved for high-profile properties, basement conversions have become increasingly popular among homeowners in London seeking to maximise space without relocating.
Although the process can be complex and involves several stages, a well-managed basement project can deliver incredible results. In determining the most suitable type of basement for your property and budget, as well as design development and construction, it should go without saying that expert guidance is essential throughout.
At SimplyEasy Refurbs we have extensive experience in delivering high-quality home renovation and basement conversion projects. Our team of industry professionals is committed to achieving exceptional standards on every build – and we are supported by recognised industry accreditations and comprehensive warranties.
The full basement conversion process has several steps, so being familiar with them will provide clarity on each stage and offer inspiration for your own project. We’re not interested in gaping or mystery, so if this page leaves any questions unanswered, please get in touch with the SimplyEasy Refurbs team. Once you’ve contacted us, we can arrange a site survey, and our senior surveyors will discuss your requirements in detail.
We offer a complete design-and-build service for basement conversions. This allows us to manage every aspect of your project under one roof, preventing bottlenecks and miscommunications between teams. We have found this approach to significantly reduce the organisational pressures and stresses for homeowners that are often associated with major home renovations.
When we describe a complete design-and-build service for basement conversions, we mean the initial site survey, architectural and structural design, planning coordination, and full construction management.
Each basement conversion project is assigned a dedicated Project Manager, supported by a carefully vetted building team. You will not be required to juggle multiple email threads and missed calls with building personell. Throughout the process, your designated Customer Service contact will remain available to provide consistency and answer any questions, ensuring the project progresses smoothly from start to finish.
A basement conversion is a major investment, and careful consideration is required before proceeding. Key questions to address include:
A basement conversion effectively adds an entirely new floor to your home, providing valuable additional living space. This can be particularly beneficial for families in London who wish to remain in prime locations but require more room. You might already have a loft conversion, or own a ground floor flat with no option for a loft.
Rather than moving home, a basement conversion allows you to expand your existing property while modernising and reinvigorating your living environment.
Like with any renovation project, setting a realistic budget is crucial. Basement conversion costs vary depending on factors such as size, type, complexity, and specification.
High-end features such as swimming pools, spas, or bespoke finishes will significantly increase costs. More classic layouts such as kitchens or living spaces require a comparably more modest investment. You tend to get what you pay for, so beware any ‘too-good-to-be-true’ quotes. We always recommend allowing a contingency of approximately 10% to accommodate design refinements or unforeseen changes.
Following an initial site survey, our surveyors will provide a detailed and transparent cost estimate tailored to your requirements.
Basement construction can be disruptive, particularly during excavation and underpinning stages. For this reason, many homeowners choose to vacate the property during construction.
In certain circumstances, disruption can be limited through phased construction, but this is not always possible. If temporarily relocating is not feasible, it may be worth reconsidering the timing of your project.
There are four primary types of basement conversion, each varying in scale, cost, and application.
A SimplyEasy Refurbs surveyor will assess your property and advise on the most suitable option.
A full basement conversion extends beneath the entire footprint of the property, including existing extensions. This option provides the maximum additional space and is ideal for larger facilities such as swimming pools or leisure areas. Natural light is typically introduced via front and rear light wells.
A half basement extends only beneath the original structure of the house. It is well suited to kitchens, living areas, gyms, bathrooms, or additional bedrooms and can still add substantial value.
Constructed beneath the garden rather than the main house, a garden basement causes less internal disruption and allows homeowners to remain in the property during construction. These spaces benefit from increased natural light through glazing and are often connected via an external staircase.
Coal cellar conversions create small, non-habitable spaces, typically used for storage or wine cellars. They generally do not require light wells.
The sky, or perhaps the earth, is the limit with basement extension design. Architectural design can be just as exciting – and well lit – when digging down. Common design features include:
Positioned at the front, side, or rear of the property to introduce natural light.
A partial intermediate floor that creates visual connection between levels and enhances architectural impact.
Glass panels at ground floor level allowing light to pass into the basement while creating a striking design feature.
Full-height glazing to light wells for a dramatic internal and external visual effect.
Multi-level outdoor spaces connecting basement and garden areas, ideal for entertaining.
An initial site survey, during which your requirements, budget, and feasibility are assessed. Measurements are taken, and preliminary layouts prepared, which is then followed by a detailed quotation.
Technical investigations are undertaken, including soil analysis, drainage surveys, water table assessment, and arboricultural reports where required. Structural engineers and waterproofing specialists also collaborate to ensure long-term durability and compliance with local regulations and requirements.
Once designs are approved, planning permission and Party Wall matters are addressed before construction begins.
Construction is typically divided into:
The overall process can take up to 12 months from design to completion, depending on planning approvals and project complexity. We have delivered faster – and longer – projects, so please do bear this in mind with your planning.
Our initial visit and quotes are free, so if you have a space you'd like to see transformed, simply contact us
Most basement projects will require planning permission, particularly where light wells or external alterations are involved. Requirements vary by local authority and conservation status, and as our team has experience with all London authorities, we can help you with your expectations around how long that process takes.
A Party Wall Agreement will be legally required for basement excavations affecting neighbouring properties. Notices must be served in advance, and disputes can delay projects if not managed properly. We provide guidance throughout this process to ensure compliance and minimise delays.
At SimplyEasy Refurbs, we are proud to deliver fully bespoke basement conversions with a professional, client-focused approach. From your first consultation through to long after completion, we remain committed to your satisfaction.
We provide:
If you are considering a basement conversion — whether for a cinema room, gym, bar, or additional living space — SimplyEasy Refurbs is ready to help bring your vision to life.