House31 Balham home extension, South London property expansion images, English residential design

House31 in Balham, Wandsworth, South London

6 October 2025

Architecture: Cox Architects

Location: Balham, Borough of Wandsworth, South London, England, UK

Photos by Matt Clayton Photography

House31, Balham, South London

House31 is a masterfully re-imagined Victorian home, transformed from a tired, dated dwelling to a vibrant, light-filled living space that harmoniously blends heritage and modernity. Located in the heart of Balham, London, this remarkable renovation project showcases the power of thoughtful architecture in honouring the past while embracing the present and anticipating the future. The original house, dating back to around 1890, has been meticulously restored to retain its generous proportions and original features, while a crisp, modern extension has been added to create a striking contrast between old and new.

The architectural response to the brief was refreshingly restrained, with a simple, white-rendered extension flooded with natural light through generous and strategic glazing. This approach, informed by the family’s Mediterranean heritage, has created a suntrap that lifts the mood year-round, with light becoming not just a design feature but a cultural necessity.

The innovative ‘kitchen courtyard’ design, a green pocket that mirrors the lushness of the rear garden, offers a moment of pause and greenery in the heart of the home, flipping the script on suburban renovations and allowing ‘al fresco’ cooking…via the large sliding hob-side window.

Throughout the project challenges were met with ingenuity, from carving out a functional loft space with limited head height to upgrading insulation, replacing windows with double glazing, and installing underfloor heating and smart meters to track energy use in real time. Sustainability was integral to the build, with planning consent already granted for solar panels and an EV charge point, setting the stage for a future-proofed home that not only honors its heritage but also embraces a greener future.

House37 is a testament to the potential of bold, architectural re-imagining, offering a blueprint for those seeking a characterful and contemporary home that balances the best of the past with the demands of the present.

How did the “heritage led” approach influence the design decisions for House37? What specific elements of the original house were preserved or highlighted, and how were they integrated with contemporary design?
Responds architect Steve Cox;
“For us, treating the original building with respect meant being clear that what was being added did not try to imitate it. Once that was established the trick was then to decide where to draw the line and avoid being dogmatic so, for example, we kept plaster details but didn’t try to extend them where walls had been changed.

What did you do and what difficulties did you encounter?
The works were as follows:

1. Ground floor rear extension
2. Loft extension
3. Complete internal refurb to allow for new plumbing/wiring/heating finishes etc

We’ve included in the press pack a few construction photos to show how comprehensive the internal refurb was. It was hard for Alessandra and I to go to site at this point without stressing over just how much work would be needed to put everything back together!

Where we added to or changed the existing building we aimed to do this in contemporary style in a clear & legible way. Otherwise we retained and re-used the existing fabric. There were some grey areas – replacement double glazed sash windows for example or the 4 panel internal doors – but we tried to follow the concept as far as we could without being dogmatic.

How did the “heritage led” approach influence the design decisions for House31? What specific elements of the original house were preserved or highlighted, and how were they integrated with contemporary design?
For us, treating the original building with respect meant being clear that what was being added did not try to imitate it. Once that was established the trick was then to decide where to draw the line and avoid being dogmatic so, for example, we kept plaster details but didn’t try to extend them where layouts had been changed.

To what extent did budget play a part in what you were able to achieve or how much you had to compromise?
We’d originally planned to include the front and rear gardens and a basement utility room into the first phase of the design but, these had to be postponed to ‘phase 2’ on budget grounds.

During the build we were lucky to get good trade discounts on some key products (thank you Domus tiles) which helped control the budget. Otherwise we splurged on some items (specialist glazing) and saved on others (Ikea kitchen). Luck played it’s part too, we found the original floor finishes in hall and living rooms all in good condition under thick carpet so were able to retain them.

Give me the background to yourselves and how the project came about
It’s our family home so myself, my Italian wife Alessandra and our two kids, Sidney (13) and Joan (17).

Alessandra works in finance, I’m an architect and we’d previously lived for 15 yrs on the next road over in Balham, London SW12.

We bought this property in Nov 2023, started building work April 2024 and moved in Jan 2025. That’s quite quick and I’d like to take a bit of credit for that though mostly it was down to the builder.

It’s Victorian in style but was actually built around 1900. It’s in a small Conservation Area and there are only five like it in the street. The rear gardens are unusually long by London standards (25m +) and south facing, which was partly why we bought it.

The other reason was that it was relatively intact – though run down – so presented a good base for refurb & extension without having to undo too much.
(NB names have been changed)