Seamless, Light-Filled Spaces That Transform the Way You Live
At Armstrong Simmonds Architects, we design bespoke rear extensions that enhance the quality of everyday life. Whether you’re seeking an open-plan kitchen, a contemporary family living space, or a better connection to your garden, we create thoughtful architectural solutions that respond to your lifestyle, complement your property, and maximise natural light and flow.

Aside from providing you with a beautiful design, your architect needs to navigate complex
planning and building laws that regulate the construction industry. Therefore, appointing a
practice with the right amount of experience is the key to a smooth project delivery. Although
not essential, appointing a RIBA chartered practice is also an important factor to consider.
Being RIBA Chartered means that the practice must adhere to a code of conduct of
professionalism and ethics which ensure quality control within the Architectural industry. The
experience of the practice within London is another important factor to consider, particularly,
as each borough has different modes of operation which can influence the design process.
Whilst the National Planning Policy Framework (NPPF) provides the backbone for planning
policy, each individual borough will have its own set of policy and guidance. A particular
challenge within the borough of London is the planning process for basement design. For
such a complex undertaking, stringent planning requirements must be met in the form of
traffic reports, geology surveys and more. Another challenge is the added complexity of
working with historic buildings. If your building is within a conservation area, a designated
building of interest, or a listed building, any work to that building or surrounding area will be
subject to strict requirements that are typically more rigorous than standard planning
requirements. London Architects and designers must ensure their clients are advised
appropriately on the process and that suitable consultants are appointed to conduct the
necessary work.
A rear extension is one of the most effective ways to add space and improve functionality particularly in period and terraced homes across London. Extending towards the garden allows for reimagining ground-floor layouts with spacious kitchens, dining zones, or versatile family areas filled with daylight and garden views.
With space at a premium in London, a well-designed rear extension can offer flexibility without the disruption of moving.
From our Battersea studio, we work across the London boroughs, offering a complete architectural service tailored to each project:
We begin by understanding your aims and assessing the site. We explore design options to make the most of available space, natural light, and movement through the home.
Our team prepares the required drawings and submits planning applications on your behalf, liaising with local authorities. Given we were founded in 2010, we have exceptional experience in dealing with planning departments.
We incorporate elements such as bespoke glazing, sliding or folding doors, rooflights, and soft landscaping to create cohesive indoor-outdoor living environments.
We produce comprehensive technical drawings and collaborate with structural consultants to provide a coherent technical design package
Throughout construction, we administer the contract, carry out regular site visits, and oversee project implementation to help deliver the design as intended.


No two extensions are alike. Our portfolio ranges from sleek contemporary additions in glass to more traditional brick-built designs that blend effortlessly with period façades. Across all projects, we focus on:
Whether your aesthetic leans contemporary or classic, we tailor every element to reflect your brief and aspirations.
As a RIBA Chartered Practice with a strong portfolio of residential work, Armstrong Simmonds Architects has an excellent reputation and are well regarded amongst homeowners across London. We bring together creative thinking, technical precision, and deep local knowledge to deliver rear extensions that are as functional as they are enduring.
We are glad we found Armstrong Simmonds Architects to help us on our first project. We had bought a run-down terraced house near Clapham Common with the goal of extending and refurbing to increase value. John initially impressed us by first listening carefully to what we wanted to do, then showing us creative ways to achieve the results and finish we were looking for.
Safe to say we certainly have managed that and both John and Alan have been instrumental in doing so. The guidance and consideration at every step have exceeded our expectations and Alan’s attention to detail during the build has been critical for the high standards we have set for this project.
They have provided us with a service which reflects every stage of the design and build. Starting with the initial drawings, schedule of works, tendering and interior design. We also employed ASA for Contract Administration to be the key middle-man between us and the builder, which they were happy to help.
We are now underway with our second project with ASA and they have been able to deliver the final drawings for planning within a fairly tight time frame, without hindering on quality. I know the whole team worked hard to help bring our vision to life and it’s been brilliant working with them over the last 18 months. They have shown a great ability to solve any issues that arose quickly and are able to communicate effectively with different contractors at all levels. I have no doubt the next redevelopment project will go well.
We chose Alan and John for our extensive project and incredibly pleased with that choice and the result. We have a Victorian terraced house and wanted to do a classic loft conversion and ground floor extension. The Armstrong Simmonds team provided a vision which achieved our goals, but with a design we could have never have thought of ourselves which we love. We used them from start to finish and are incredibly glad we did. Alan supported us through the tender and renovation processes, and we are incredibly pleased with the end-product and the quality of work of builder Cezar of Vecchini. We would highly recommend Armstrong Simmonds for their vision, design thoughtfulness and exceptional assistance through the project. Thanks team!
We worked with Alan and the team from Armstrong Simmonds for 3 years from start to finish to achieve the full renovation of a London townhouse. It was a challenging brief given the nature of the property but collectively what has been achieved is an outstanding end result. Alan and John thoughtfully incorporated our vision with the realities of converting an old Victorian house and the scrupulous attention to detail, symmetry and balance achieved in the design were instrumental in us choosing Armstrong Simmonds in the first place.
In addition Alan supported us through the tender and during the renovation working with our excellent builder Cezar of Vecchini to deliver the brief. I would highly recommend if you are looking for a team to turning your vision to the end product with a very high attention to detail while still being good humoured and a generally great guy to work with. Thanks again team. Dom and Kamilla
John and his team have been brilliant to work with for our full house renovation and extension in SW London. Our house is quite unique and that combined with it being in a conservation area we knew it wouldn’t be a straight forward planning process – but Armstrong Simmonds did a fantastic job and helped us navigate us through every step. We couldn’t be happier with the detailed design and outcome.
If you’re thinking about a rear extension in London, we’re here to guide you. Whether you have a vision in mind or are just exploring possibilities, let’s unlock the potential of your home together.

Architect's studio