Denmark Hill SE5

first floor extension
Colomb St SE10
end terrace house extension
West Street DA7


How a Property Went From 71sqm to 293sqm in Just Four Months

Lucky for you, we documented each step that we took to renovate this mid terrace property in Conservation Area by adding multiple storey extensions and converting into maisonettes. Use this proven process to produce the same results for your property conversion project.



Every project has its obstacles, and this project was no different. Most importantly, because the property is in a Conservation and Archaeological Area, we were faced with several design restrictions. The former designation would prevent us from making any changes to the existing shopfront. The latter pertained to the excavation on the basement level. Moreover, after we submitted our application, the council asked us to make some amendments to the first-floor layout, requiring us to find design solutions that would cater to the needs of both our clients and the planning authority. With the rear extension being an infill development, we would have to find a way to bring light into each of the units.

We also had to handle certain practical issues, such as the location of the refuse and cycle storage. With no space outside the property, we were tasked with finding some extra meterage internally. Finally, the basement level was in disarray when we arrived, so we would have to find a way to reimagine this neglected space. We were also careful to survey the property’s inherent opportunities.

To that end, we examined the surrounding area, seeking out precedents that might provide us with some flexibility moving forward. Luckily, we observed that the neighbouring property had already obtained permission for a large rear extension. This was key, as we could cite this existing extension when making our argument to the council. We also noted that the surrounding properties had mansard roofs while ours did not. Since, in a Conservation area, the design must “enhance and preserve” the context of the surrounding area, we could build upward with a mansard roof extension, which would provide us with plenty of space for the upper flat. With these opportunities and challenges in mind, we ventured forth.


To address the above-mentioned challenges, our designs would have to optimise the given space, using extensions, where possible, to offer more room for the desired flats. Starting on the ground floor, we knew we would have to retain the storefront in order to maintain the style of the surrounding area – as per the Conservation Area requirements. At the same time, we were keen to provide more space to the commercial unit by excavating beneath the garden, thereby extending the basement. Likewise, on the ground- and first-floor, we knew that, with the precedent extension on the neighbouring property, we would likely get permission for a large double storey rear extension covering the entirety of the garden. Because this was an infill extension, we were sure to include windows all along the rear elevation and a skylight on the ground floor. With the excavation and the rear addition, we could provide future tenants with plenty of space to run a business.

Moving upward, with the double storey rear addition, we had ample meterage on the first floor for a one bedroom, two-person flat. To the rear of the property, we placed an open-plan kitchen-living-dining area, flowing seamlessly into the double bedroom at the front. On the second and third floors, we took advantage of the triple storey rear extension and the mansard roof addition, offering future occupants an abundance of space. We designed the second storey to contain two bedrooms (one double and one single), a bathroom and storage space. On the top level, made possible by our upward extension, future occupants could relax in their large open-plan kitchen-living-dining area, where they would also enjoy sunlight cascading through the skylight and windows to the front and rear of the property.

As for the refuse and cycle storage: we used space on the ground floor in such a way that occupants could easily store their bicycles beneath the stairwell and their rubbish in a storage area adjacent the front door. To make these designs possible, we submitted one full planning application for everything, and with a few minor changes, we were able to win the council’s approval. This was a major success for two reasons. First, to get planning permission for a project that includes excavation – and to do this in an Archaeological Area – is no easy feat. Second, it’s no straightforward task to pursue multiple extensions for a property in a Conservation Area, adding 222sqm extra space. Despite these obstacles, we were still able to successfully secure consent for our client’s proposed development. With permission in hand, our client could now pursue a profitable scheme, renting out the flats on the top floors and the commercial unit on the ground floor for a decent sum of money. At the same time, future occupants would have more than enough space to enjoy a high quality of living in their day to day lives.

Of course, the benefits of using our services extend far beyond the results above.

We surveyed our clients and asked them to name the three benefits of our services that they found most useful. Here are the top benefits as cited by more than 100 survey respondents.

  • Get access to proven strategies

  • Have a dedicated architect

  • Minimise risk and feel safe

  • Make the project stand out

  • Save time

  • Save money

  • Save effort

  • Get photorealistic 3D visuals

  • Increase space

  • Increase comfort

  • Increase value

  • Get access to Urbanist Project App™




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