The new structure’s form and material palette refer to those of the existing house in a contemporary way while embracing the beautiful surrounding Sussex landscape
Tell us about the project
Our clients are a family of four with a love of architecture. They bought a house in Sussex which had originally been an apple store for the nearby manor house, and the grounds still contained two large greenhouses. The brief was to replace one of these with new open-plan kitchen/dining and living areas as well as a master bedroom suite. The extension needed to embrace the beautiful landscape setting, which the existing house didn’t do.
The existing house had a central circulation spine with accommodation wings on either side and a utility room at the end. That route is extended into the extension, which is connected to the house by a glazed link. A small courtyard space was created in front of the link, framed by an existing decorative brick arch with the old and new structures on either side.
Within the extension, the large open-plan kitchen/dining space has floor-to-ceiling windows orientated towards the garden and landscape beyond. This bright, open space is visible and draws you through as soon as you open the front door.
Beyond the kitchen is a sunken living room with a window that aligns with the circulation spine, giving a view of the garden all the way from the front door, some 30m away. Set off to the sides of the circulation spine are a new WC, additional side entrance, breakfast room and stair up to a first-floor bedroom, which sits above the sunken living room.
How was the planning process?
The extension is as large as the existing house, which is unusual and meant that there was some work to do in demonstrating that it was sensitive to the site and to neighbours. Its footprint was deliberately kept similar to that of the large greenhouse structure it replaces, and the form and material palette refer to those of the existing house in a contemporary way.
Explain the external treatment
Three pitched roofs echo the three pitched roofs of the existing house but are turned 90 degrees to open up views to the garden and landscape beyond. They extend to varying lengths to create canopies where required. Each relates to a different space beneath: dining, kitchen and the master bedroom above the living room.
The extension is made from two key materials: a base of brick, chosen to blend well with those of the existing house, and black standing-seam zinc roofs that reference the local rural vernacular. There is a continuous datum line between the zinc and the brick that emulates the strong eaves line of the existing house. It’s high enough to avoid accidental dents and scratches to the metal.
The join between the two materials was quite hard to get right because two different wall build-ups sit on top of each other. Designing that is one thing, but it’s another to get different subcontractors to understand how things line up and create a crisp shadow gap that runs around the whole building. It’s always a battle but it was achieved successfully here.
How have the interiors been designed?
The interiors are designed to be simple and minimal while reflecting the building's external materiality. Brick walls continue from inside to out, bringing warmth to the interior. Polished concrete floors give a continuous flowing surface to the new parts of the house. The new spaces are enlivened by the colourful joinery of the kitchen, window surrounds and benches. Attention has also been paid to light fittings and switches, adding interesting, detailed touches.
What was the approach to sustainability?
Sustainability was a key driver of the brief. One of the clients was also the structural engineer and paid particular attention to minimising the use of steel. The project also included extensively insulating the existing house and providing much better levels of thermal performance in the extension than the building regulations required. Oil heating has been replaced with an air-source heat pump that supplies both the extension’s underfloor heating and the existing house’s radiators. This is in part powered by 16 new photovoltaic panels on the extension roof.
What was the biggest challenge, and how did you overcome it?
Originally the scheme was designed with blackened timber cladding to the pitched roofs but the client encountered difficulties with insurers because the roof structure is also timber. Working with suppliers, we did everything we could to convince them of its benefits and suitability but to no avail.
That meant the design had to be revisited after planning consent had been gained. A new application using black zinc was thankfully accepted by the planners but delayed the construction design and could have been a bigger issue had we been unable to find an alternative that satisfied both planners and insurers.
If we were to propose similar materials in the future, we would look into the insurance situation early in the design process. The reaction of different insurers seems to be unpredictable; it’s a detail that is seen quite a lot in Scotland, for example.
The enforced design change did not ultimately detract from the finished building but it did waste time and effort.
What is your favourite feature of the building?
As you approach the house, the extension itself is hidden from view and there are few indications of its overall scale. There is a great moment of surprise when you enter and look down the full 30m length of the circulation spine to the window at the end, seeing all the interesting spaces that articulate it along the way.
We think the way the original building has been adapted to work with the new additions has been particularly successful, enhancing the whole scheme. It’s unusual to have a house of this size that is almost entirely on one floor; it could end up feeling like one of those bungalows that is just a collection of rooms off a long corridor. By emphasising the circulation spine, drawing it through into the extension and drawing the eye to big open-plan spaces, the whole house now works in harmony and makes sense from the moment you walk in.
David Parsons is a co-founder of Selencky Parsons Architects
Total contract cost (excluding kitchen and glazing) £420,000
GIFA cost per m2 £2,360 (average figure across new build, and refurb but also includes the hard landscape)
Existing refurbished area 43m2
Extension area 135m2
New hard landscape 127m2
Architect Selencky Parsons Architects
Contractor Chalmers & Co
Zinc VM Zinc Anthra zinc
Brick BEA Luna Apollo
Kitchen Uncommon Projects
Polished concrete Steysons
Windows The Door Company