Basements Are
Our Business

We have been building bespoke basements in London for over 35 years

We have been building bespoke basements in London for over 35 years


As a family business, we pride ourselves on customer satisfaction and word of mouth referrals. We have built our reputation as experts in basement construction and design thanks to the dedicated team of in-house specialists that we work with. We like to operate a clean and tidy site and employ staff who share our values. We always work to a JCT contract and can offer a full ten-year insurance back guarantee on all of our basement constructions.



Assigned JCT contract

Our commitment to deliver your project on schedule and on budget

35+ years of experience

Clients have confidence in our knowledge, expertise and word of mouth referrals

Insurance backed guarantee

We are able to offer a full 10 year insurance backed guarantee at a premium for our basement construction works if required

Family-run business

Honesty, loyalty and trust are what define our business values

A stress-free build

We assign a dedicated project manager to keep your build running smoothly

No sub-contractors

Being a close-knit team means we can keep all our work in-house
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    I under-estimated how useful a basement conversion would be

    I under-estimated how useful a basement conversion would be – it’s the one room that we now use most in the house. I’d definitely recommend Cool Basements to any of my clients and contacts.

    Adam Pearson

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    The team was very flexible, responsive and provided us with some great advice during the design and planning permission process

    James Little was extremely good at working with architects, building engineers and the Council. We were also impressed with the meticulous attention to the building and engineering requirements while being imaginative at maximising the aesthetics of the building.

    Solomon Soquar

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    James, Peter and the team are a highly knowledgeable, competent and professional outfit

    They kept us fully informed as our project evolved and worked collaboratively with us to resolve unforeseen problems. As busy professionals, we simply left them to get on with it, which they did. The team were always punctual, reliable, tidy and friendly which certainly helped with neighbours. We’re delighted with our end result and finish, and would certainly hire them again.

    Sonia Gogna

  • Prebend-Gardens-Chiswick-2-1-scaled.jpg?w=1024&h=768&scale

    James, Peter and their team were both professional and accommodating, nothing was too much trouble

    We are delighted with our new basement and very pleased with the work carried out by Cool Basements. James, Peter and their team were both professional and accommodating, nothing was too much trouble. Everyone who worked on the project were courteous and friendly and had a great attitude, I very much enjoyed working with them and was made to feel part of the team! James did an excellent job making sure that everything came together to create a wonderful finished new space. I would highly recommend to others.

    Mr Hudson


Have a question? We are here to help!

  • What building regulations apply when constructing a basement?

    Building regulations apply to all basement construction. This covers areas such as fire escape routes, ventilation, ceiling height, damp proofing, electrical wiring and water supplies. Underpinning and foundation work may also be needed. You must also consider the Party Wall Act 1996 if other properties adjoin yours and you share walls.

  • What planning permission do I need for a basement?

    Planning regulations covering the creation of living space in basements is evolving and under review and can vary from county to county and from borough to borough in London.

    Converting an existing residential cellar or basement into a living space or excavating below the footprint of the original house is, in most cases, unlikely to require planning permission. However, excavating to create a new basement which involves major works, a new separate unit of accommodation and/or alters the external appearance of the house, such as adding a light well, is likely to require planning permission. If you live in a listed building you are likely to need consent for internal or external work.

    In all circumstances you are advised to contact your local planning authority for guidance on local policy before starting any work. At Cool Basements we have a dedicated team of architects and planning consultants who will advise and take care of planning requirements on your behalf.

  • What insurances/guarantees do you have?

    Our aim is to give our customers complete peace of mind so we go above and beyond the usual guarantees. We work to strict JCT building contracts, set out by the joint Contracts Tribunal, which means we ensure every element of the build is accounted for and completed on schedule. In addition, we can offer a full ten-year insurance backed guarantee on all our basement constructions, which covers labour and materials. We use state-of-the-art tanking systems that come with a ten-year warranty and we offer a one-year warranty on minor defects such as cracking.

  • I am thinking about extending into a basement – what do I do next?

    Adding a basement to your property can bring fantastic benefits. We can help you to explore the options so you get the most out of your new living space. The first step is to get in touch. We will then arrange a free site survey and initial consultation to understand more about your requirements. Every client is assigned with a dedicated project manager who will manage your build from the design stage through the planning process to the final construction and fit out. Read more about our simple seven-step process and take a look at our basement ideas for inspiration.

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