Design & Build Basement Conversion London

We are Design & Build basement conversion company in London specialising in Design, Excavation, Construction, Waterproofing and Fit-outs. We can accommodate any basement build or conversion requirement in South West London.


Frequently Asked Questions

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.

Party walls stand on the land of two or more owners and form part of a building. This can also refer to garden walls. In accordance with the Party Wall Act 1996, you must tell your neighbours if you want to carry out any building work near or on your shared property boundary, or ‘party wall’, in England and Wales. Cool Basement’s experienced party wall surveyors will act on your behalf to secure the appropriate party wall agreements.

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 offer a full ten-year insurance backed guarantee on all our basement construction, 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.

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 gallery and Instagram for inspiration.

Enjoy a new dimension

In the core of Architect7’s design process is the architect client relationship. We carefully listen to our clients and take responsibility for building an honest dialogue based on trust and understanding.

We are constantly curious, wanting to fully understand the client’s aims and objectives, and to interrogate exactly how the building will be used. This is our inspiration, ensuring that the resulting architecture is relevant, and directly derived from client and user needs.

Our sector leaders remain alert to the latest trends and research, infusing emerging designs with bespoke new thinking. As well as addressing the needs of users, we ensure that our designs don’t cost the earth and have a positive impact on their physical and social context.

We examine your options to give you the most appropriate advice and detailed information on costs and timescales.


For help with your project…

Call or email now to discuss.

0333 772 7253