Design & Build Basement Conversion London


Our RIBA chartered architects have extensive experience working in the conversion of basements, as well as constructing modern extensions and additional storeys. We work closely with the local Planning Authorities in London and pride ourselves in obtaining all permissions approved on time.

Our comprehensive approach delivers the finest results that are truly individual, transforming your ideas into breathtaking spaces.

How We work

Typically, we like to arrange an on-site visit to understand your vision, and get a feel of the space we will be transforming. We then go back to the drawing board and provide you with a couple of initial draft ideas, which we are confident will provide you with the inspiration to realise your unique vision.

If this sounds of interest, you can request a free consultation and we will get in touch to discuss your project.


Before beginning the project there are a number of stages that we can help you with here at APT Basements. Most projects need planning permission or a lawful certificate if you want to extend or alter the property’s exterior. We have the capability to design your project with you to create that personalised unique end product.



A full measured survey is conducted. It takes between seven to ten working days to produce the CAD Drawings showing the existing structure and layout.



Our design team will then work with you to create that unique design you are looking for ensuring that we work to your budget. This process normally involves two or three face-to-face meetings and takes between four and five weeks.



Once your design is finalised, we are happy that it won’t conflict with structural requirements and it fits within the council’s guidelines, we prepare and submit your application for planning permission or permitted development. We then act on your behalf for the eight week process responding to any enquiries and making sure that the application stays on track.


Once the design and planning are in place there is still a lot that needs to be organised before work can commence. This includes choosing your contractor and often tying up any loose ends before we can get your project to site. Party Wall Awards, Temporary Works Designs, Licences to Alter all happen during this stage (this list is by no means exhaustive). Most importantly this is where we generate the quote to build your project.



This involves one of our pricing team to visit your property, talking through your design so that they get a full understanding of what you want to achieve and then generating a detailed quotation. This is a very detailed element of work and can take up to ten days to complete.



This is something due to its requirement of impartiality that we cannot offer in-house; but we can recommend good surveyors we have worked with in the past and can assist you with any information they require. This process can take up to eight weeks and is one of the most common cause of delays on a site.



Vital to a successful project is producing a detailed programme setting out the key stages of the build. The programme highlights the key elements (kitchens, glazing, sanitary ware etc.) that need to be synchronised to ensure timely delivery to site.



Once the quote is agreed we generate a contract for the works. This is normally either Federation of Master Builders or a JCT contract but we are happy to work with other types too. Attached to the contract will be the detailed programme and the payment schedule should no contract administrator be appointed.



We are very comfortable working with the local council’s building control teams but are also flexible should you wish to appoint an independent surveyor.


The build is where we cut our cloth – for the duration of your project you will be in the capable hands of one of our project managers. They manage all items required on site, and forecast realistic lead times that will ensure the project is running on time and inline with the agreed quote and specification.



Before your start date we introduce you to your Project Manager and Site Manager who will be with you for the duration of the project.



For the duration of your project we will ensure that our sites are compliant with all health and safety principles, we monitor temporary works and manage all liaison with the council and building control. We constantly check the standard and quality of the work. We have considerable experience of working with all specialist sub-contractors, should they be required and use all the latest modern technologies and materials.



For the duration of your project we like to have a weekly meeting to keep you abreast of what is happening, and check on the progress if the customer supplied items and to ensure the project runs smoothly without any delay.



During the finishing stage, the site will become a hive of activity with specialist tradesmen applying the finishing touches to the build. Once our specialist tradesmen have finished we can then carry out the final install of AV, furniture and soft furnishings.



At the end of the project, we will carry out a complete inspection of the works with you and together we will sign off the project. You will be left with all the manuals, warranties and instructions for equipment that has been fitted in your newly renovated home.


We are committed to upholding our most cherished values in every project and task we take on.

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For help with your project…

Call or email now to discuss.

0207 223 6417

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