Basement Conversion London

Are you looking for a team to handle your basement conversion project in London? Look no further than our expert basement construction and conversion company in London. With years of experience and a team of skilled basement conversion specialists, we excel in turning unused basements into beautiful, practical areas tailored specially to your requirements. We at Basement Conversion London are here to be your trusted construction partner from the start till completion.

Your Leading Builder of Basements in London


Our comprehensive design-to-build service specializes in all aspects of basement conversions. Based in London our expertise covers everything from design and excavation to construction, waterproofing, fit-outs, and even new build basements. With our design and skilled construction teams, we are confident in our ability to handle any basement project of any size and complexity in and around London. We specialise in 100% custom basement conversion projects from drawing up your plans and applying for planning permission till the finishing touches.

Whether you're looking for an entertainment area, a children's playroom, a gym, or a home office, for workdays, We are ready to turn your vision into reality. When you choose Basement Conversion London you can expect a transformation experience guided by a team of experts who specialize in basement conversions. Let us help you shape your dream basement environment. 

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Why Opt for a Basement Conversion in London?

Basement conversions have gained popularity in London for several reasons and if you're considering this option rest assured that you're not the only one. Moving to a house may seem like a solution but it comes with its own set of challenges and expenses such as high moving costs and stamp duty. So what's the alternative? Choosing a basement conversion in London is a way to expand your living area without the need to move.

Facing Costs and Limited Space in London? Look Below!

As the property market in London continues to soar, we are increasingly seeing homeowners realizing the potential of their existing properties. Many London properties often reach their extension limit above ground which leaves us wondering, "Where to extend?" The answer lies beneath our feet – a basement conversion. By converting basements, homeowners in London can effectively maximize their living space without the need to relocate to a new property—a move that could present financial burdens or necessitate leaving a prime location.

To put it simply, the increasing trend of converting basements in London is a reaction to the city's property situation. It provides a solution for space while also adding value to properties and improving quality of life. 


Feeling Cramped?

Families in need of more space should consider converting their basements.. It's a practical solution that allows you to create additional rooms without the hassle of moving. By converting their basement, families can customize their living space to meet their specific needs.

Craving Personalization?

Whether you desire a home gym, an entertainment hub, or a wine cellar, it's time to make it happen. Don't wait any longer to unleash your creativity and turn your basement into an incredible space.

Versatility in Utilisation

One of the aspects of basement conversions lies in their versatility. Whether you desire a bedroom, a home office, or even a small private cinema—the options are limitless.

Property Value

A well-executed basement transformation not only gives you more living space but also significantly increases the value of your home, in the London market.

Planning Regulation

Regarding permissions and regulations basement conversions in London can usually be done within the boundaries of "Permitted Development Rights " making the planning permission process relatively easier compared to other types of extensions.

Long-term Investment

From the other perspective while a basement conversion requires an investment it can also bring long-term financial benefits. For example, you can potentially generate income by renting out the space—especially considering that rental income tends to be high in a city like London.


Don't miss out on the opportunity to add more space to your home. Whether you want a games room for the kids, a state-of-the-art home cinema, or a home office space, we can turn any vision you have for your basement into reality. Start exploring the potential ideas of your property today—the dream basement you've always wanted is a few steps away! With a basement conversion you can say goodbye to the challenges of moving or dealing with expensive stamp duties. Basement conversion offers practicality, cost-effectiveness, and creativity for homeowners. Get in touch with us for a free no-obligation site survey and quote.


Are you looking to convert your basement without the added stress? At Basement Conversion London, we understand that home improvement projects can be challenging. We aim to make your basement conversion journey as smooth and stress-free as possible. Our experts will strive to minimize disruptions to your daily routine and keep noise as minimal as possible. We are committed to managing noise levels and ensuring a smooth experience for you and your family.


Maximizing your Space with Basement Conversion London

At Basement Conversion London, we understand that two basement conversions in London are never the same, not only because of the different selection of property and space available but also because of the individual tastes and lifestyles of Londoners. Do you have an idea for a basement conversion that you want to discuss? We offer a free site survey of your home and can show you some of our recently completed basement conversions across London. Our team will provide you with an affordable estimate for the work needed and a completion timeline too.

Basement Conversion London can oversee every step of the basement conversion process with our in-house architects; from obtaining planning permission and approval needed to create your dream home, right through to the actual digging out, construction, and fit-out. If you have your architect we are happy to work to your specific needs. We provide a comprehensive package of basement conversion services which includes an all-in-one design and build packages to help you build your perfect hassle-free basement conversion in London.

All our basement conversions in London and the other counties that we complete are tailor-made to the customer's specific requirements. Your needs will be discussed in detail when you meet our team of surveyors. We work with the best team of basement conversion contractors in London to deliver our work. 

Basement conversions offer an opportunity to transform your area into something special. Whether you're looking for a family playroom, a wine cellar, or even a self-contained unit with its entrance the options are endless. Unleash the potential of your basement by considering these ideas for transformation in London. When thoughtfully designed and constructed basements can serve any purpose you desire.



For a free site survey please fill out the form below and we’ll get back to you as soon as we can.

Our Basement Projects

Basement Conversion London is experienced in working with homeowners across London and the home counties. Our full end-to-end service means that we will be with you from start till the completion of your Project. If you like to see our work and find out more about the new builds we have built close to your area, then contact us for a site viewing.

Take a look at our selection of Basement Projects below 

Understanding the Planning Rules for Basement Conversion in London

Before you start your basement conversion project in London it's essential to have an understanding of the planning rules. Each borough in London has its regulations when it comes to basements so being familiar with the restrictions to your area is crucial. This knowledge will not shape your project. Also, helps you avoid any potential complications in the future. Navigating through these planning restrictions can be quite challenging. The basement policies vary from one borough to another. Can impact aspects of your conversion, including design considerations, feasibility assessments, application requirements, and even cost implications. To provide you with examples of how these policies differ;
In Wandsworth, if you plan on having a lightwell in your garden it is important to ensure that at least 50% of the front garden remains intact after excavation for the lightwell.
Merton Council's basement policy states that constructing a basement should not exceed 50% of the property's rear or side garden areas.
The Royal Borough of Kensington & Chelsea limits basement excavation depth to no more than that of a story.
Understanding these guidelines will greatly assist you in navigating the planning process for your basement conversion project in London. In Westminster, a new policy was implemented on September 1 2016 which involves a levy and the establishment of a group called the "basement nuisance busters." This group is responsible, for managing the impact of basement construction on traffic enforcing working hours, and addressing any complaints that may arise.
Before embarking on a basement conversion project in London it is crucial to familiarize yourself with and adhere to your local authority's basement policy and guidance. This initial step will ensure that your project aligns with the regulations resulting in a more predictable process. Always remember that a successful and hassle-free basement conversion begins with being aware of the rules. By planning and understanding these regulations you can set yourself up for a project that meets all requirements.

Planning Regulations in London

Ensuring the Value of Your Basement Conversion in London

The next step on your journey to converting your basement is about making sure it adds value to your property. Here at Basement Conversion London, our team of experts will guide you through understanding the return on investment (ROI) before you start the project.
Striking a Balance; Weighing Cost against Value

To ensure that your basement conversion is worth the investment, conduct thorough research and seek expert advice from real estate agents in your area. Compare prices based on real values of properties sold with basements converted. By determining the precise value it can add per square meter, you can confidently proceed with the conversion, knowing that the cost will align with the value it brings. This approach guarantees a solid ROI and will help you make a sound decision about your basement conversion.
Maximizing Your Investment
Considering the state of the property market, converting your basement can be an advantageous endeavor. However, to reap benefits from your basement project it's crucial to;
1. Understand the Local Market; By researching and gaining an understanding of the market trends you'll be able to plan your basement conversion in a way that maximizes its added value to your property.
2. Seek Professional Advice; Consulting with real estate agents nearby who have insights into market trends and potential returns will enable you to make informed decisions throughout this process.
3. Plan Your Budget; With an understanding of how much value your basement conversion can bring, planning a budget that strikes a balance, between cost and value will help ensure an ROI.

In summary, converting your basement in London offers the benefits of expanding your living space and boosting the value of your property making it a smart investment decision.

Does a Basement Conversion Add Value?

Carrying Out Important Surveys for Your Basement Conversion in London

The third step to achieving a basement conversion in London involves conducting a series of surveys. These surveys will guide the design process provide information for the planning application and help identify any technical challenges that may arise during construction.
Types of Surveys Required for Basement Conversion
Before commencing your basement conversion project you will typically need to complete the following surveys;
1. Soil Structure Survey; This survey examines the composition of the soil at the desired excavation depth. Identifies any concerns related to the water table level. This information is vital to ensure a stable basement construction in London. More information about Soil Surveys.
2. Drainage Survey; This survey determines the location of drains around or beneath your property and garden. Understanding this helps assess how the basement construction might impact your existing drainage system. Depending on drain placement you may require an agreement from your water utility provider known as a "build over" agreement. Read more about the Drainage survey here.
3. Site Dimensions Survey; This survey provides measurements of your property which are essential for designing and planning your basement conversion effectively.
4. Tree Assessment Survey; This survey examines any trees in both your garden and neighboring gardens to evaluate their susceptibility to damage during excavation, for the basement. To proceed with your basement conversion, in London, it's important to consider any trees that may be subject to a Tree Preservation Order. Here is a great article by Crown Tree about Tree surveys

Additionally, it is crucial to conduct a Flood Risk Assessment for your property. This assessment will evaluate the flood risk. Greatly influence the design and construction of your basement conversion.
To lay down a foundation for your project these surveys play a role. The insights gained from these surveys directly impact the planning, design, and execution of your basement conversion. By conducting these surveys upfront you can proactively address any challenges that may arise.
Remember that starting with knowledge sets the path to success. Conducting accurate surveys is a step, towards ensuring a seamless and hassle-free basement conversion. It is always advisable to seek guidance during this process.

Read More About Soil Structure Surveys

Designing the Architecture and Layout for Your Basement Conversion in London

Now that you have completed the groundwork, the next step in your journey toward a basement conversion in London involves design and space planning. Here are some important pointers for planning, designing, and decorating a basement in London. 

Define the Basement's Purpose - What is the purpose of your basement and the unique requirements you have? If you want to bathroom, you need to think about the plumbing, drainage, waterproofing, and ventilation. For a home cinema, you will need to take into account the room's acoustics, install a stepped floor to optimize viewing angles, and fit dimmer switches to create the perfect visual mood. The possibilities are endless for a finished basement in London.

Determine your Ceiling Height - Ceiling height is a vital consideration for basements, not only for building regulations compliance but also for your comfort. When deciding the height of your ceiling, do not forget any ductwork or piping that may run through and reduce the open spaces vertically. 

Create a Basement Floor Plan - Basements can often feel quite cramped. To maximize the space in your basement effectively it's important to plan thoroughly. Think about how you intend to use the space, what the most common traffic patterns will be, and which parts of the room should be easily accessible. This plan will help you devise a functional layout. Check with your local building authority on how much space you will need to allow for a window that can be opened and climbed out in any case of emergency evacuations. 

Create Basement Zones - The finished basement needs to be split into different zones. Depending on what the purpose of your basement is, you can partition it to create a high-level structure which allows for a better understanding of how the space flows and where fixtures and fittings should be logically placed.

Factor the Storage Needs - Basements are more than often used as storage spaces even when their primary function is something else. Basements usually have a lot of wall space to utilize so we suggest using this to your benefit. You can use the space to install wall-to-wall cupboards and closets, or floating shelves along the walls. Make sure that your basement design facilitates all of the storage you need. We also suggest to look under the stairs as a great spot to add some much-needed storage.

Consider Lighting -  Basements are often challenging when it comes to getting light due to their submerged structure. When designing your basement in London, it's important to consider how to make the most of daylight through windows and even outdoor landscaping. Additionally, the design plan should incorporate lighting options, like recessed lights or individual fixtures considering that basement ceilings tend to be lower and hanging fixtures might not be suitable.

Select an Interior Design Style - To effectively merge all the factors to consider when designing the layout of your basement floor plan it is beneficial to have an interior design style in mind. For example, selecting the lighting should align with your choice of wall colors. 

Planning Application for Your Basement Conversion in London

The next step in your Basement Conversion process is to file for your planning application. Planning Permission differs in all boroughs of London. Some boroughs are more strict than others and clamp down on over-the-top basement conversions. Once your architectural plans are ready this step can be initiated. This important step will bring your dream basement conversion one step closer to reality.
Submitting Your Planning Application
The planning application process involves the following steps:
Complete Your Plans: Make sure all your basement conversion plans and designs are completed and ready to submit to the local council where you live.
Complete all Required Paperwork: Make sure you complete all paperwork for your basement conversion and ensure it adheres to local planning regulations in your London council.
Submit Your Application: File your planning application with a local planning office in your area. Your architect will give you all the required documents such as the plans, designs, and survey results. The application process can take up to 8 weeks from the date of submission. Within this time, the local planning officer may want to visit your property and have some questions too. They will point out any conditions required for planning consent to be approved.
Navigating the Planning Application Process

The planning application process might seem to you as a complex task however this is a very important step in getting your Basement Conversion in London. We at Basement Conversion London can handle all the planning and application process on your behalf from submission to addressing questions and any conditions raised by the local planning authority. We aim to make your Basement Conversion journey as stress-free as possible. Obtaining planning permission for your basement conversion is a significant step that brings you one step closer to the additional living space that you want to add to your London home.

Do I need Planning Permission?

Almost all Basement Conversions in London require planning permission, however, there could be some unusual circumstances where this may fall under permitted development (if you're lucky). Here are some of the permissions you will need before starting your project: Planning Permission, Building Control, Party Wall Agreement, Listed Building Consent, Highway Licence, Skip Licence, Parking Suspension, Streetsworks Licence, and Freeholder Consent.

Can Permission be Refused?

Yes, your basement can be refused if there is scope for "over-development" in the paperwork. The actual meaning of this can be different, for example, in The London Borough of Richmond-Upon-Thames, they state it as " An overly large extensions above ground level can dominate a building. An extension below can be of an inappropriate scale.

Can you Build a Basement under Permitted Rights?

Yes, in some parts of London, you can convert your existing basements from a storage area into a living room. This can be done under Permitted development rights unless you reside in a conservation area or your property is a listed building. If you complete the basement conversion work under Permitted development, then you will need to apply for a lawful development certificate from your local authority. By doing this you can prove that your scheme met the requirements and did not need any planning permission. You can see the PD criteria on the UK government's planning portal but we highly recommend checking with your local council before you commence any sort of basement construction work in London.

Building Regulations for Basements - Your basement conversion project has to meet the building regulations in England and Wales for you to make it legally habitable. Some of the building regulations are, installing adequate levels of insulation, creating emergency escape routes, and having a minimum head height which is required for structural work such as steel beams. All structural work undertaken is inspected by the building inspector to ensure it will not have any impact on your house or your neighbor's properties. 

Read More About Planning Permission in Basements

Technical and Structural Design for Your Basement Conversion in London

Congrats! Your planning application is on the way, and now you've arrived at the next exciting stage of your basement conversion in London journey - the technical and structural design. This isn't just some boring paperwork, nope. It's where you and a structural engineer sit down together and bring your basement dreams to life!
Building a Strong Backbone: Structural Design and Calculations
Think of the structural design and calculations as the skeleton of your basement conversion. They keep everything upright and in place. The stage starts with:
Hiring a Structural Engineer: Let's start by appointing an expert basement structural engineer in London. These are the experts who'll tell you the best way to design, support, and build your basement's 'shell and core' (that's a fancy term for the reinforced concrete structure in the ground).
Incorporating Survey Information: With the survey data in hand, the engineer will create a design that's a perfect fit for your property's characteristics.
Creating Drawings and Calculations: Next, your engineer will get to work on a set of drawings and calculations. These are your roadmap, outlining everything from the construction sequence, materials, steelwork, to underpinning or piling details, and party wall detailing. The engineer will also lay out the rules of the road, in terms of Construction Design & Management (CDM) requirements.

The structural design is the key that unlocks the next stage of the process. It's the detailed plan that shows how your basement conversion in London will come to life. And it's not just for your benefit – it's also required for the next step, the Party Wall Agreement. The surveyor you appoint will need to take a close look at these plans for your Award. 

Structural Design: The Foundation of Your Basement Conversion

The structural design is the actual foundation of your basement conversion project. It outlines the technical details of how your basement will be constructed ground up. The structural design engineer will ensure the basement is structurally sound and adheres to all the necessary regulations.

Once the technical and structural design is done, we move on to the Party Wall Agreement. Each of the stages and steps is crucial to make sure your basement conversion is a success.

Why is a Structural Engineer necessary?

To obtain approval from Building Regulations it is necessary to have an engineering design in place. Failing to do so could result in the devaluation of the property in the basement area. The structural design plays a vital role in this process as any errors or miscalculations could lead to damage not only to your property but also to neighboring properties.

What can I expect the structural engineer to provide and/or guarantee?

The structural engineer should have the capability to create designs and drawings that comply with the requirements of Building Regulations for the structure and construction. Based on the experience of the engineering firm, an engineer may possess the expertise to deliver a design that meets all aspects of Building Regulations enabling the construction of all relevant components.

Your Basement Conversion's Waterproofing Guide in London

Basement waterproofing becomes necessary when a structure or property or any part of it is constructed at ground level or below. In some cases, there tends to be an accumulation of water, in the surrounding ground causing the water table to rise and resulting in pressure. This pressure affects the basement floor and walls potentially leading to water seepage through cracks, joints, and structural vulnerabilities. If basement waterproofing is not carried out this water intrusion can give rise to problems, like mold growth, decay, structural issues, and other damp-related concerns.

How Basement Waterproofing Works?

Given that the basement is prone to experiencing levels of water pressure due to the accumulation of water in the surrounding ground and soil, it's not surprising that this pressure can result in cracks, leaks, and dampness issues. By applying the correct waterproofing solution you can prevent water from seeping into your basement.

To transform your basement into a functional space below your home, we offer three solutions. The first is tanking, which forms a watertight barrier to prevent moisture penetration. Another option is installing proofing solutions during the construction phase of the building. Lastly, we have a Cavity drain membrane solution that utilizes a combination of membranes, drainage channels and pumps to redirect water from your property. We can also tailor a solution by combining systems for the best results.

Ways to Waterproof Your Basement?

In the Basement waterproofing industry people often talk about the three systems, namely type A, B, and C. It's worth noting that a combination of these systems might be utilized to ensure the best and most effective solution for your basement or cellar. The final decision on which system suits your needs will be determined after a site inspection conducted by one of our surveyors.

Type A Waterproofing - Barrier System

This is where a physical barrier is used to protect the basement or cellar walls and prevent water from getting in. Type A waterproofing, commonly known as "Tanking " involves applying membranes, waterproof cement, or a slurry, to the walls below ground level. For new basement constructions, Type A external waterproofing applies the tanking barrier membrane. Slurry, to the outer wall of the structure, preventing groundwater from entering. During building renovations or after construction, Type A waterproofing can be installed on the basement walls.

Type B Waterproofing - Integrated Systems

This pertains to the waterproofing solutions that are incorporated into the building structure during the construction phase. Typically Type B waterproofing includes using reinforced concrete and implementing a water control mechanism to prevent any water seepage through construction joints (like a hydrophilic waterbar). It is important to involve our team of waterproofing specialists right from the initial design stage of your project if you wish to have a Type B system installed on your property.

Type C Internal Waterproofing

This method is considered the most up-to-date technique for waterproofing a basement or cellar. It involves combining a waterproofing membrane, basement floor drainage, and a sump pump to effectively and securely remove any water. To create a dry internal surface Cavity Drain Membranes utilize a studded membrane that lines the walls and floors.

Afterward, the walls can be dry lined or Plastered, while the floors can be screeded or overlaid with materials like waterproof floorboards or tongue and groove flooring. Sealed systems are used in conjunction with either a cavity drain system or a sump pump when dealing with water or flooding. On the other hand ventilated systems are used in situations where there is no water and when traditional damp-proofing methods are not suitable. Both of these systems can be designed to comply with BS8102, which is the code of practice governing waterproofing structures.


Effective Waterproofing Techniques

Party Wall Agreement: Your Basement Conversion's Legal Lifeline in London

In basement conversion in London, the Party Wall Agreement is a legal framework for avoiding and resolving problems regarding boundary walls, party walls, and excavations that are close to your neighbor's buildings. If your soon-to-be renovated basement shares a boundary or a wall with your neighbor within a 3-meter radius, chances are you will need to draw up a Party Wall Agreement. Exceptions do exist for those blessed with deep foundations, so you might just strike gold there! If you live in a detached house, you will not need this party wall agreement. All shared walled properties will need to reach an agreement with their neighbors before starting the conversion process. 

Decoding the Party Wall Agreement
The Party Wall Agreement is like the invisible handshake between you and your neighbors. It's here to ensure everyone stays informed during the building works, with no surprise feud sparking off.
Before you start any construction process, you need to serve notice to your neighbors at least 8 weeks in advance. In most cases, it takes about 4-8 weeks to get the Party Wall Agreement wrapped up for straightforward projects. But remember, like a complex puzzle, the more pieces (or complex issues) you have, the longer it can take.
Appointing a Party Wall Surveyor: A Universal Guide
When you embark on the Party Wall Agreement process, it's good etiquette to chat with your neighbors about choosing a single, shared Party Wall Surveyor to represent all parties. The Party Wall Act 1996 insists that this surveyor remains as impartial as a referee, guarding everyone's interests.
But sometimes, neighbors like to bring their surveyors to the party, which can make things a tad more complicated and time-consuming.
Need a Party Wall Surveyor?
Need help to find a Party Wall Surveyor? No worries! At Basement Conversion London, we're here to help. Alternatively, you can consult with the Faculty of Party Wall Surveyors (FPWS) or the Royal Institute of Chartered Surveyors (RICS).
Secure Your Basement Conversion with a Party Wall Agreement
Securing a Party Wall Agreement is ensuring a dispute-free basement conversion in London. It's your legal shield that keeps everyone on board and informed. We stress to take this step seriously as it can ensure a stress-free basement conversion process.

Why Do You Need A Party Wall Agreement?

Engaging a Basement Contractor for Your Basement Conversion in London

Hiring the right building contractors for your basement conversion in London can be the difference between an efficient, well-planned, and executed project to one full of issues. At Basement Conversion London, we see your basement as two different projects, the first being the shell and core build and the second being the basement fit-out.  

Basement Shell and Core Construction - This stage involves the building of the waterproof, concrete structure of your basement. We stress to only hire a contractor who is a basement specialist like us. A general building contractor in London might not be well-versed or experienced in dealing with the issues of basement construction. It's important to hire a basement construction company that undertakes the work itself and not just subcontracts this task.

Basement Fit-Out -This stage involves the interior finishing and decorating of your basement. Most basement contractors in London only focus on shell and core build and are not experienced in completing the full fit-out work. We at Basement Conversion London can deliver both services efficiently. 

Sequencing Your Basement Conversion - Our team believes that the most efficient way to manage your basement conversion project is to start with the shell and core works first. As the excavation work is ongoing, you can then focus on the interior design of the basement. 

Creating Your Dream Basement Conversion in London - Selecting the right building contractors for your basement conversion in London is very important and more so if you can streamline your project accordingly. By differentiating the shell and core construction to the fit-out phase, you can better manage each stage and can complete a basement conversion that meets your unique needs and increases your property's value.

How Deep Does a Basement Conversion Need to Be? The depth of your basement conversion depends largely on how you are going to use it. Whether you add a small gym a utility area or a cinema room, you can get away with a lower ceiling height in comparison to a living space that matches the original house. If you want to have bedrooms then, you can expect to dig deep, around 4 to 4.5 m to obtain a high ceiling. The advantage of having a high ceiling is that it gives the basement a bright and airy feeling and less claustrophobic in comparison to the lower ceilings. 

Basement Conversion Guarantees and Insurance

At Basement Conversion London, we believe it's very important to have guarantees and insurance in place. This safeguards our customers if anything goes wrong with your basement construction. Rest assured you will be covered. Take the following scenario, your basement starts to leak and the contractors who built it are no longer in business. In this dilemma how will you fix the problem? In addition, when you decide to sell the property buyers inquire about the guarantees in place. 

At Basement Conversion London, we advise our customers to take into account the following:

Builder Company Guarantees: This is the guarantee from the London basement conversion builders that the work undertaken will be free from any defects for the stipulated period. If any issue arises within this timeline due to poor workmanship or poor materials, the builder will be obliged to fix the problem at no extra cost.

Waterproofing Guarantees: These are usually divided into three categories, starting with:

The Design Guarantee: This covers the waterproofing design, ensuring it's fit for purpose.

The Product Guarantee: This covers the waterproofing materials used in the basement construction, assuring that they'll perform as expected for a certain period.

The Installer Guarantee: This guarantee is from the installer, assuring that the waterproofing system has been installed correctly.

Insurance Backed Guarantees (IBG): An IBG is an insurance policy that provides cover if the original contractor ceases to trade and is, therefore, unable to honor their guarantee. This could be due to any reason such as bankruptcy, liquidation, death, or retirement.

Latent Defects Insurance: This is also known as structural warranty insurance. This covers the cost of remedying structural defects that become apparent after the completion of the basement building project. These are defects that were not detectable at the time of completion and take time to appear on the surface.

Building's Renovation Insurance (Joint Names): This is the type of insurance taken out by the builder and the client together. It will cover the client and the contractor for any loss or damage to the works and site materials during the period of renovation. 

Each of the above forms of protection plays an important role in managing and deterring the potential risks involved in a basement conversion project. Always ensure that the necessary coverages are in place before beginning any work.

Basement Inspections and Excavations

During the construction phase, it is important to appoint an approved Building Control Inspector from the local authority in your Borough or a private one. Their role will be to monitor the progress of the construction work and ensure that the basement structure complies with the Building Regulations. The inspector will visit your project site in stages, which will be coordinated by your basement contractor.
Excavation and Construction of the Concrete Box
Once all preliminary tasks have been completed we can finally begin with the basement construction work. This stage involves excavating the basement area and creating the structure commonly referred to as a " box." Basement Conversion London ensures we follow the build to your design specifications. We ensure that all work strictly follows the approved design and avoids any modifications as that can lead to issues down the line. 
At a level here are the main steps involved in the construction process;
Excavation; After confirming that the site is safe and ready for construction Basement Conversion London's team will start digging out space for your basement. We undertake this task with care to avoid any damage, to your house foundation or nearby structures.
Foundation work; If it is required, we may need to underpin your foundation to handle the weight added by having a basement.  To evenly distribute the weight of the building this process involves extending the foundation either in depth or breadth.
Constructing the basement; Once the area is prepared, we start building the concrete structure of the basement. This forms what we refer to as the "shell" or the basic structure of your basement. 

Waterproofing; Once the shell build is complete, we take measures to waterproof it and prevent any moisture from seeping into the basement. This includes applying specialist waterproofing materials to the walls and installing a drainage system if needed.

Inspections; Throughout these stages, your Building Control Inspector will conduct inspections to ensure that all work is being carried out in accordance, with approved plans and regulations.
Remember, maintaining communication, with your contractor during this process is crucial. Keeping a line of dialogue will help resolve any issues or questions that may arise promptly

Interior Design of the Basement

When it comes to designing the interior of your basement you can start once the construction of the basement shell and core is underway. 
There are factors to consider for your basement design as well, as specific requirements for fixtures and fittings;
1. Roof lights and light wells; It's important to have these in place to allow light into your basement improving its atmosphere and livability. Read more about lights in the basement here
2. Windows, both internal doors; The choice of windows and doors can greatly impact energy efficiency, security, and the overall aesthetics of your basement.
3. Staircase, floor, and wall finishes; Opt for finishes that are durable moisture resistant, and complement the design of your home.
4. Sanitary ware, tiles, and paint colors; These elements play a role in creating a look throughout your basement.
5. AV (Audio Visual) security systems IT networks; Make sure you plan for installations such, as visual equipment, security systems, and network access points.

6. Heating, Ventilation, Air Conditioning: You will need to plan on how you will heat, cool, and ventilate your basement to maintain comfort and avoid moisture and damp build-up problems.

7. Light fittings, and furniture selections: These selections will be determined by your overall design theme, personal style, and budget too.

You can hire a professional interior design company to give your basement a nice design and an efficient project flow too. Interior designers can help in creating a cohesive design scheme and advice on certain product selections too. Given the number of products, materials, and finishes that are required to be selected, an experienced interior designer can make the process easier and help you avoid any unforeseen issues. 

Do remember that when hiring an interior designer, check that they have the technical knowledge within the basement construction sector. They should be experienced in understanding all the technical details and designs such as lighting plans, floor layouts, and more. If possible tell them to create a CAD package of drawings and detailed specifications which will allow us as the building company to get clear instructions when building your basement. 

London's House Market, House Prices, and Basement Conversions

The London housing market is experiencing a surge in demand for living options. Families looking for extra living room professionals need workspaces. There is a growing need for extra living rooms for child caregivers. However, the challenge of finding homes in London can be daunting. Fortunately, there's a practical solution; basement conversions. Homeowners can now utilize their existing basements or even excavate new ones to create additional living space.
Basement conversions are especially great when it comes to designing areas, for children. Imagine creating a playroom where kids can have fun with friends without worrying about damaging belongings or compromising their safety. It's also a relief knowing that they are a step away and enjoying themselves.
One of the benefits of basement conversions is the value they add to your home. These home renovations can greatly increase the value of your property making it more appealing if you're considering selling it in the future amidst the rising London housing market. Imagine this; When you sell your house you're not just offering a home but one, with a unique basement. It's a standout feature that many potential buyers will find difficult to resist. Having rooms can boost a property's value by 10 to 15%. If your house is located in London converting your basement could potentially add 20% to its selling price.

Looking to increase the value of your property in London? Why not consider transforming that basement into a living area? In today's property market, every square foot is valuable. A basement conversion can make a significant difference. Imagine turning a gloomy basement into a guest suite or even an independent living space complete, with its kitchen and bathroom. By doing you not only enhance the usefulness of your home but also potentially boost its value by 20-30%. It's like discovering treasure, under your roof!

But it doesn't stop there; converting the space into a self-contained flat could generate income allowing you to recoup your initial investment and continue earning profits. However, it's important to note that quality matters when it comes to the basement conversion. Simply applying a coat of paint won't cut it. Proper insulation, waterproofing, and complying with building codes and permits are aspects that require expertise. An executed job adds value to your property.

Don't forget about the location aspect well. If your property happens to be, in one of the prime neighborhoods in London, the added value could be even greater. Certainly, there is a cost involved. You may have to put up with some construction noise for some time. However, when considering the long-term increase in value and the potential for a source of income this temporary inconvenience becomes well worth it. It is advisable to seek expert guidance before proceeding, such, as consulting with a property valuation professional or a structural engineer who can provide insights. So why wait longer? Take advantage of your London home's hidden potential. Enhance its value by converting your basement today!

Cost of Basement Conversion in 2024

Free Consultation: Your First Step Towards a Fabulous Basement

Step right up and kick-start your basement journey with us. Here at Basement Conversion London, we believe in the personal touch. We like to begin with a friendly face-to-face, where we can get to know you and your dream basement project. And remember, we're talking about a completely free consultation here!

Who's in the Meeting?

Unlike other companies, we don't have salespersons and we don't subcontract, so rest assured you'll be chatting directly with the ones who will be guiding your project every step of the way.

What's on the Agenda?

We'll run through all the options for your project, ensuring we fully understand your vision. Whether it's a swanky new home cinema, a sophisticated wine cellar, or a simple, cozy living space, we want to make sure we get it spot on.

When will I get my Quote?

We know you're eager to get cracking, so we won't keep you waiting. We'll have a quote ready for you faster than a cat can wag its tail - typically within two to five working days!

Let's get this show on the road, shall we? Get in touch with us today and let's start turning your dream basement into reality!

Investing Downwards: The ROI of Basement Conversions in London

In the city of London, where space is at a premium, homeowners are exploring downward expansion to create more living areas and potentially boost the value of their properties. Basement conversions have emerged as an investment opportunity in London's real estate market. What is the Return on Investment (ROI) when it comes to transforming basements in this cosmopolitan city? Let's dig deep and discover the hidden potential beneath our feet.

A Desirable Space Solution

London's real estate market is constantly evolving with a demand for space, homeowners are seizing the chance to enhance their property value by extending downwards. By converting basements into stylish spaces there is potential to transform previously unused square footage into prime living or working areas.

A Lucrative Financial Outcome

Basement conversions in London can indeed lead to gains. According to experts in the industry, a well-planned and executed basement conversion can increase your property's value by 10 20%. Considering London's already soaring property prices this percentage represents a boost.

Considering Investments

However, embarking on a basement conversion project involves more than focusing on the value. It's a decision for homeowners to consider factors such, as construction costs, legal permits, and design complexities. In the heart of London, the cost of converting a basement can vary depending on factors like the size and complexity of the project. So it's important to analyze the investment potential to ensure a return on investment (ROI).

Catering to Market Trends

One overlooked aspect is tailoring the conversion to meet market demands. This could involve creating a home office that caters to the growing trend of work or designing an extravagant leisure area complete with a home theater and wine cellar. Aligning your basement conversion with market demands can significantly boost its ROI.

Embracing Sustainability; An Added Benefit

Today buyers are increasingly interested in energy-efficient homes. By incorporating eco features into your basement conversion you not only reduce your carbon footprint but also enhance the property's appeal in the market and consequently increase its ROI.

The Importance of Expert Guidance

To fully unlock the ROI potential of a basement conversion in London it is crucial to partner, with experts who understand both the market intricacies and technical aspects involved in projects. Their guidance can streamline the process prevent mistakes and maximize your investment returns.

In conclusion, embarking on a basement conversion in London is an opportunity that holds the potential for increasing the value of your property and meeting the demands of modern living. It's not about gaining space but also about unlocking possibilities and seeing your property become a profitable asset.

Worth investing in a Basement?


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 Basement Conversion London offers you a full design and build package to complete your basement as you wish


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FAQ's about Basement Conversion answered

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

  • Must there be an existing cellar on the Property?

    No! having an existing cellar is not a pre-requirement for building a basement. We have built and converted Basements for many property owners across London who do not even have an existing cellar or any form of underground space.

  • How Much Head Height Can Be Achieved?

    We believe in creating space that is comfortable and habitable and basement conversion London understands that ceiling height plays a big role in achieving that. As Basement Conversion London, we advise having a minimum head height of between 2.3 to 2.4m. If this is less for you, we can dig further and lower the floor.

  • Can I live on the Property while my Basement is being Built?

    Absolutely, it's possible to remain living on the property while basement construction is ongoing. Our clients at Basement Conversion London are aware that there will be noise, dust, and some disruptions due to construction activities. In addition, certain utilities might need to be turned off temporarily during some phases of the construction.

  • Do you need Planning Permission for Converting a Basement?

    Yes, converting a basement in London into a living space does require appropriate planning permission. As there will be considerable structural changes therefore Planning Permission will be needed to ensure that these modifications meet local building codes and regulations.

  • How Long Does a Basement Conversion in London Take?

    The duration for a Basement conversion in London can vary widely depending on factors such as the size and complexity of the Basement project. The actual construction and waterproofing process typically can take between 7 and 20 weeks. Before the Basement construction starts, you will need time for planning, designing, securing, and approvals. In total, a complete basement conversion project can often take six months to a year from start to finish, sometimes even longer for larger or more complex projects. This includes time for unforeseen delays, which can be fairly common in construction projects.

  • Do you offer any guarantees on the work?

    We offer a 10-year guarantee on all building works undertaken by Basement Conversion London

  • Can I create a basement of more than one level?

    Yes, it is possible to create a multi-level basement under your London property, given the right geological conditions exist, structural considerations are considered, and planning permission is granted.

  • Will my Basement be affected by Damp?

    No - it's imperative to understand that when your basement is built appropriately using the best materials, then damp or water damage should not be an issue. At Basement Conversion London, we install the Delta Membrane system which is one of the leading waterproofing solutions used in basement constructions. The membrane creates a barrier that prevents water from passing into the interior of the basement. Regular maintenance and checks of the system (especially the pumps) are also crucial to ensure long-term performance.

  • Do I need to inform my neighbours about the proposed Basement Construction?

    Yes! If your basement construction project in London involves work on a shared wall with a neighbor (a "party wall") or digging within a certain distance of a neighbor's building or boundary,

  • Can I take the Basement Conversion beyond the footprint of the House?

    Indeed, it's possible to extend a basement beyond the footprint of your house, into the garden, or under other parts of your property. Planning Permission will be required as well as feasibility checks to see several factors such as the site's characteristics, local planning policies within the local London borough, and the proximity to your neighbours properties.

  • What is the average cost of a basement conversion?

    The cost of a converting your basement depends on various factors such as type of the basement project, features required and your current condition of the property. If we have to take an average scenario, building a new basement range from £3000 to £5500 per square meter. Converting an existing cellar will range from £2000 to £4000 per square meter. Extending an existing basement to the garden might set you back between £2,800 to £4,300 per square meter. However, these figures don't include professional fees and finishes, which could add 15-20% to the cost. Unexpected expenses may also occur, so it's wise to budget an extra 10-20%. In high-value locations like central London, expect costs to be on the higher side. And remember, high-end finishes and complex features will add to the overall expense


What can we do for your Basement?

For a free site survey and design consultation please fill out the form on the right and our team will get back to you as quickly as possible.

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