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Coloured cement sets the tone at EBBA’s Cast House

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Benni Allan

Eco-cement and brick form the rough base for the upper level's material refinement at this extension of an east London Victorian house

Who is the project for and what was the brief?

The project was designed for a young couple that wanted a distinctive yet refined home, fit for their growing family. Both are creatives and involved in property development and interiors, which meant it was a close collaboration both with the clients and the interior designer. This gave scope for architectural expression and ideas on the home’s arrangement.

It was important that the plan provided a sequence of spaces that would accommodate the clients’ active lives and their need for both moments of calm and space to host family and friends. At the same time, it had to work hard to ensure there was generous ancillary space for storage, which would then offer clutter-free rooms for relaxation.

The brief required a balance between more flexible informal spaces to live and work, and formal living rooms and places to work/study. The plan also had to maximise views out to the garden while bringing light deep into the house.

  • Credit: Building Narratives
  • Credit: Building Narratives
  • Credit: Building Narratives
  • Credit: Building Narratives

What was the existing building like and what work have you done?​

It was a Victorian home in east London, which we refurbished and extended. We wanted to maximise opportunities for light while creating small moments of calm. The result is a robust extension reflecting a bold cast facade, coupled with intricate timber detailing. Wall textures and beautiful floors throughout help to celebrate the idea of making more with less.

We have created a new large open-plan kitchen with adjacent dining area, framing new views to the garden and beyond. A vaulted ceiling introduces a unique feature inspired by Roman arches and the client’s interest in travel. A tiled floor runs from the garden into the living space, connecting and extending the rooms, to give a sense of expansiveness. The lowered section of the living space and kitchen are divided by a change in level, to create a different atmosphere within the same space.

Similar detailing in a refined yet textured palette follows upstairs into the rest of the house. A calm master bedroom leads to a walk-in wardrobe and ensuite. Everywhere we have paid attention to making the most of joinery and linings to elevate the feel of each room.

Credit: Building Narratives
Credit: Building Narratives

Was the planning situation?

The extension had to comply with requirements to provide a setback from the neighbours, which worked with the project’s intention to provide a side courtyard which would eventually become lush and green.

How did you treat the exterior?​

The feature facade is cast in a pigmented eco-cement with a subtle brown tone, finished in a technique that brings out the aggregate, reminiscent of Brutalist architecture. Between the rougher elements are a series of screens that act as pivots that can open wide, better connecting to the garden. We had to work closely with the contractor to develop the method of construction and final finish, aiming for a result that worked to enhance the character of the house – a response that felt sensitive yet quietly radical.

How did you design the interiors?

We are always keen to create a backdrop for the personality of our clients to come through. On the Cast House, however, we also developed a scheme with the interior designer, Anahita Rigby, using tones that felt earthy and warm. The choice of terracotta floors and warm tiles helps ensure a comfortable environment while keeping detailing clean, adding to an airy feel.

The material palette gets more formal as you move up through the house, starting with the patina from the cast concrete and the brick slips on the ground floor, moving to the warm wood tones from the sapele up to darker more intimate timber in the bedrooms.

Credit: Building Narratives

What is your favourite detail in the project?​

The cast facade was done in situ and later finished by hand to bring out the aggregate and make an intervention that feels crafted yet robust. We always enjoy the opportunity to experiment and add something unique that can transform a house. The facade and the arrangement of the ground-floor rear addition together help to give a sense of grandeur as well as making spaces that accommodate the lives of the young family.

The facade creates a deep reveal to the interior and helps to bring warmth through its tone and the way light reflects into the living area. At the same time, its textures give a richness in materiality that shows the hand of the maker, while its form helps to frame the house both internally and externally.

What was the biggest challenge?

The house was started during the pandemic and a lot of the suppliers and materials kept changing due to supply issues. This meant that details and the final finishes had to undergo continual testing and refining while also making sure everything could still be achieved within budget.

Benni Allan is a founding partner of EBBA 

See more interesting house extensions

  • Credit: Building Narratives
  • Credit: Building Narratives
  • Credit: Building Narratives
  • Credit: Building Narratives
  • Credit: Building Narratives
  • Credit: Building Narratives


Total contract cost: £281,000
Area 170m2
GIFA cost per m2 £1,652

Architect EBBA
Natural plaster walls Eco Concrete
Contractor Duck & Bear
Interior designer Anahita Rigby
Stylist Sophie Surridge

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