Basement Conversions Chiswick

Transform your unusable space in Chiswick with a Basement Conversion. Gain extra storage or living space and improve your home.

Basement Extensions in Chiswick

Our team possesses expertise in all facets of designing and constructing basements, whether it is for pre-existing basement areas or newly extended ones. From excavation to waterproofing plumbing to electrics and finishing touches like plastering, tiling, and painting. 

We provide two types of services for basement conversions;

1. Complete service including design, specification, and construction.

2. Construction service as subcontractors.

For basement conversions in Chiswick, we take care of everything from designing the layout to arranging investigations and ensuring compliance with all regulations. As subcontractors for basement construction projects in Chiswick, our skilled craftsmen meticulously execute approved plans by the main contractor. In both scenarios, Basement Conversion London ensures that your basement is built and decorated to perfection using the best sourced materials.



We specialise in high-quality custom Basement Conversions across Chiswick and around other areas in London. We have built numerous bespoke basement conversions in Chiswick which are fully tailored to the client's personal requirements and preferences. Our Basement Conversions in Chiswick allow families to add habitable space to their homes without the need to move home. We offer you a complete design and build package with a turn-key option too. We cover everything from design, excavation, construction, waterproofing, fit-outs, and all other basement conversion requirements.

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At Basement Conversion London, we are fully committed, to delivering a transparent basement conversion experience in Chiswick starting from the concept all the way to the final completion. Our comprehensive approach begins with a site survey and a meticulous design phase. We then create drawings and detailed structural calculations, which form the basis for a customized quotation tailored specifically to your basement project in Chiswick. Once you approve our quotation our skilled architects take care of obtaining planning permission ensuring that construction can begin smoothly. Throughout the construction process we maintain open lines of communication keeping you informed and involved at every stage. Finally, we work diligently to successfully complete your basement conversion in Chiswick. Our dedicated team is always available to discuss any aspect of your basement project in detail ensuring that you are completely satisfied.


Basement Construction Costs Chiswick

Looking for a stress-free basement conversion service that is specifically tailored to meet all your needs? Our team of professionals will begin by conducting a complimentary assessment of your property followed by providing you with a detailed and accurate estimate. This estimate covers every aspect of your basement construction project ensuring transparency and clarity from the beginning. Our quote will cover all aspects of the basement build including the costs of:

  • Stage 1: Excavation
  • Stage 2: Efficient disposal of waste materials
  • Stage 3: Underpinning for stability
  • Stage 4: Thorough waterproofing and tanking solutions
  • Stage 5: Selection of subflooring materials
  • Stage 6: Inclusion of all materials and labour costs
  • Stage 7: Internal Fit out and finishing work.

With our expertise you can trust that your basement construction in Chiswick will be streamlined and well-coordinated process from start to finish. The Average basement costs in Chiswick starts from £150,000 plus VAT. Read more about a Basement Conversion in London

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Chiswick Housing Market and Basement Conversions

In the housing market of Chiswick, where it can be difficult and expensive to find a home, many families are looking for alternative options to accommodate their growing space requirements. Whether it’s creating a family area, setting up a home office or even an annex for the guests or children’s nanny. Basement conversions offer a practical and cost-effective solution. It's worth noting that basement conversions are not limited to properties with existing basements or cellars. Even homes without these features can undergo this transformation providing a way to expand your living area. One significant advantage of basement conversions in Chiswick is their suitability for children. These spaces can be cleverly converted into playrooms that cater to the needs of youngsters. Here children can enjoy activities with their friends in a safe environment reducing the risk to themselves and your precious belongings. This imaginative solution not only maximizes the potential of your property but also ensures a perfect balance between functionality and family life.

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Hassle-free Basement Conversions and ROI

Basement conversion a great way to boost the value of your property especially in the thriving Chiswick housing market. By adding a basement, you can increase the value of your home by 10 to 15% and, in some areas across London this figure can even reach up to 20%. However, we understand that home improvement projects often come with worries and complexities. At Basement Conversion London, we specialize in creating stress free basement conversions specifically designed for Chiswick properties. Our aim is to minimize disruption to your life. From designs and obtaining planning permissions to structural calculations and construction work we take care of everything for you. Each project is assigned a Project Manager who will be your go to person for any questions or concerns you may have. With Basement Conversion London, transforming your basement in Chiswick isn't about increasing the value of your home; it's also, about enjoying a hassle-free experience from beginning to end.

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Guest Lounge



Swimming Pool


Wine Cellar


Kids Room

Stages of your basement extension project in Chiswick


From the moment you contact Basement Conversion London, we make it our priority to provide you with the best possible service. From the initial meet up at your property in Chiswick, our office team will always be available to answer any questions or concerns you may have. Our dedicated project manager will also be available to offer support and guidance throughout the basement conversion process.


We understand that every basement project in Chiswick is unique, and that's why we offer a fully inclusive service that can be tailored to your specific needs. Whether you require the expertise of our Architectural Designers, Structural Engineers, or building control application specialists, we have the experience and skills to deliver exceptional results. We are also happy to work with your own Architectural Designers and design team if you already have one in place. Our team's flexibility and willingness to collaborate means that we can seamlessly integrate our services with those of your existing team.


When it comes to local authority approval, we understand that navigating the regulations and requirements can be a daunting task. That's why we take care of all the necessary paperwork and submissions on your behalf. We will ensure that your project in Chiswick is compliant with all building regulations and requirements and that all documentation is submitted correctly to your local council authority in Chiswick.

Upon commencement of works, your dedicated Project Manager will be onsite all day every day, providing you with a single point of contact for any issues or updates regarding the project's progress. We believe in clear communication and transparency, and our Project Manager will keep you informed every step of the way.


A Building Inspector will make an appointment to visit at regular stages throughout the project in Chiswick, their job is to ensure that we are adhering to all the latest building regulations. Upon completion of works, the Building Inspector will make a final visit and you will be issued with a completion certificate.


Upon completion of all basement conversion works in your Chiswick home and having gained approval from The Building Inspector we will supply you with all relevant safety certificates.


Tanking and Waterproofing

Tanking is the superior building technique for underground structures that effectively controls water infiltration from the external soil. Our method utilizes draining channels to remove excess water, while a robust tank surrounds the walls and base of the basement, protecting it from infiltrations. We employ top-of-the-line cavity drain membranes, channel drains, and sump pumps, installed redundantly with alarms to ensure flawless operation. Our secondary pumps take over when the primary fails, while alarms signal any issues with the correct functioning of the pumps, such as battery exhaustion. Waterproofing is an essential component of any structure, underground or overground, to prevent dampness caused by water infiltration. At Basement Conversion London, we pride ourselves on our in-house expertise to design and implement the latest technologies and the most effective waterproofing systems, ensuring your basement is built to last.

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Planning and Permitted Development Requirements

In Chiswick, permitted development for basements is strictly limited to non-substantial alterations. Any excavation for a basement must have planning permission, which requires a complex application process involving extensive documentation, reports, investigations, and specific conditions unique to basement conversions. However, the approval rate for basement conversion planning applications is typically very high, as councils frequently grant permission. While the result is predictable, the application process is longer and more costly than standard extension applications, such as loft conversions or rear extensions.


Shell-and-Core and Fit-Out

When it comes to converting a basement, choosing the right basement conversion company in Chiswick is crucial. With Basement Conversion London, you have access to a pool of highly specialized basement builders for every stage of the project. Our construction project manager is also a structural engineer, ensuring that the final structure of your basement is not only safe and solid, but that the entire process is carried out with maximum safety and control.


During the shell-and-core phase, we excavate and extend the volume of your basement, using temporary supports to protect your existing structure. The result is a waterproof, reinforced concrete box that forms the external structure of your basement. We only work with subcontractors who have a proven track record of successfully damp proofing basements. Trust Basement Conversion London to deliver a basement conversion that is safe, reliable, and built to last.


The subsequent stage is the fit-out, comprising of electrical and plumbing work, wall construction, flooring, lighting, plastering, and painting. With Basement Conversion London, you need not fret about locating the suitable tradespersons for each task. Our project manager will oversee everything and keep you informed on the project's status, schedule updates, and decision making at the appropriate juncture. They will assist you in clarifying your necessities and making decisions throughout the fit-out's duration until it is finished.


Do you have a question about Basement Conversion in Chiswick? Below we have listed the most frequently asked questions.

  • Why Should I Convert my Basement in Chiswick?

    If you have outgrown your home and are finding it difficult to move due to the current housing market, a basement conversion may be the perfect solution for you. By adding a whole new floor to your home, you can create a luxurious space for a home gym, cinema room, bedroom, bathroom, entertainment area, or even a swimming pool. Don't hesitate to invest in a basement conversion if you need extra space but don't want to move. It will completely transform your home and give you the space you need to live comfortably.

  • Is Planning Permission Required for a Basement Conversion?

    Planning permission may be required for a basement conversion in Chiswick, depending on the situation. However, building regulations must always be followed. Our expert basement contractors will guide you through the entire process and handle all necessary applications for planning permission and approvals.

  • Do I need to have an existing Basement?

    You do not require an existing basement for your conversion. Basement Conversion London has the expertise to construct your basement from scratch and can provide guidance on the options available for your property.

  • Do I need to move out during the Construction Process?

    Clients are not required to move out during the construction of their basement. It is completely optional and up to their preference. However, it is possible for clients to live at their property during the conversion process, even when heavy work is being carried out.

  • What is Basement Waterproofing?

    Basement waterproofing is a crucial process that effectively halts water damage in below ground areas of your property in Chiswick. Our team of basement waterproofing specialists are equipped to determine the most suitable waterproofing system, based on the construction, and intended use of the area. Trust us to provide the necessary solutions to protect your property from water damage.

  • Are Basement Conversions in Chiswick worth it?

    A basement conversion in Chiswick is an excellent solution to expand your property and boost its value by 10-15%. If you already have a basement, it's a wise decision to make. Don't hesitate to add extra space to your home with a basement conversion.

  • How long does a Basement Conversion in Chiswick take?

    A basement conversion project in Chiswick typically takes several months to complete. We confidently handle all necessary permits and permissions, ensuring a seamless process from start to finish. Simple basement conversions can take just a few weeks to complete, however, basements conversions that require digging out, pumping, floor lowering, and a number of other things can take a number of months to complete. Basement Conversion London will work with you closely to ensure you understand the timeframes involved for each stage of the basement conversion project.

  • Are there any specific building regulations that need to be followed when converting a Basement in Chiswick?

    Converting a basement in Chiswick requires strict adherence to building regulations. Safety codes, fire regulations, and structural requirements must be met without compromise to ensure a legal and successful conversion.

  • Can a Basement Conversion in Chiswick add value to my property?

    Undoubtedly, a basement conversion in Chiswick will add significant value to your property. By creating additional living space, you will appeal to a wider range of potential buyers and increase the overall value of your home. Don't hesitate to invest in this valuable upgrade that will pay off in the long term.

  • How much does a Basement Conversion in Chiswick cost?

    The cost of basement conversion in Chiswick is determined by various factors, including the scope of work, size of the basement, and addition of natural lighting. Our pricing strategy is tailored to each client, ensuring that they receive a competitive quote that meets their specific requirements. Rest assured that we offer a decisive and efficient approach to basement conversions.

  • Do you need a pumping system for a Basement Conversion?

    Absolutely! If you've experienced basement flooding in Chiswick, then it's imperative that you have a drainage and pumping system installed before proceeding with your conversion. Moisture levels in basements can be unpredictable, which is why a sump pump is the most reliable choice for ensuring your basement stays dry and protected. Don't take any chances - invest in a pumping system for your basement conversion today.