Basement Conversion London

When it comes to basements, SJ Construction is a company that ensures consistent quality throughout every element of our basement projects by offering design and building works together. Combining these two key elements enables us to work side-by-side with our clients to evolve their ideas from thoughts, to blueprints, to actual constructions. Our detailed communication, planning, and budgeting not only makes all of this possible, but also with minimal stress.

Basement Development

Rest assured, every SJ Construction project is carried out with a high level of professionalism and care. This can be attributed to the fact we work with the very best tradesmen and hand select the best team members for every unique project. Whatever you have in mind for your basement, we make it our mission to make your ideas become a reality.

At SJ Construction, we want nothing more than to exceed your expectations. Call us today to arrange a viewing.

Request a Quote

0203 859 9385


SJ Construction will provide you with a complete basement design and build service covering every aspect of your basement conversion, from the initial design stage, through submission of the basement planning application, and the detailed engineering and design process. Once all of the paperwork is in place, we will have one of our teams ready to start work on your new basement.


Once appointed we will arrange for a member of the basement design team to meet with you to carry out a measured survey and discuss your proposed basement design in more detail, including the intended use of your new basement and advising on the best layout to optimise your new space. They will then produce scheme design drawings, carry out any pre-application investigations such as tree reports, noise surveys and flood risk assessments and submit your application to the Local Authority.


Moving forward from the initial basement scheme design, should you opt for the full detailed design service, we will arrange a further meeting with the Architects London team to discuss your proposals in more detail, so that we can help you create a blueprint for your own unique basement space, including layout and proposed finishes, such as joinery, electrical and lighting, plumbing, heating, audio visual, decorative and external works. We will also undertake the structural engineering drawings and calculations, incorporating the basement works and any associated upper floor works. We will then produce detailed basement design drawings and engineering drawings showing the above, which will form the basis of your basement construction.

020 38 599 385


If you are considering the fitting out works as a separate package or perhaps you already have your own contractor carrying out other works in the property, SJ Construction can offer a Structural Shell and Waterproofing only design. Here, SJ Construction takes full responsibility for the structural basement design, waterproofing and drainage works and provides accurate costs for the basement shell. We will happily work with your architect or design team and pass on the benefit of their experience to ensure that the design and planning is both practical and cost effective.