Offroad vehicle inspires Fabric's geometric glass, zinc and aluminium extension

What is the background to this project?

The client is a family of four that lives in Knowle in the West Midlands. They wanted to increase the size of their living space on the ground floor to allow for a better flow between the kitchen and dining spaces. Their existing five-bedroom house was completed fairly recently – in 2000 – but the family felt that it failed to take full advantage of the picturesque rural setting. Additionally, the layout lacked an adequate sense of flow from the entrance through to the rear terrace, which was important when entertaining guests or on summer nights spent in the garden.

Our clients approached us because they were drawn to our ability to come up with ideas that are ‘out of the ordinary’, and hoped that we would challenge their expectations and design something remarkable. The brief focussed solely on an extension and reconfiguration of the links between the living spaces in the main house. The rest of the house remains unchanged.

The clients placed a high degree of trust in us, which really smoothed out the concept design phase, allowing us to progress quickly to the planning stage. The project took 18 months, including construction.

What were the main influences on the design?

The design was heavily influenced by a Rezvani Tank – a ‘tactical’ offroad vehicle – that we saw in the clients’ garage, and by comic books scattered around the existing home. We liked the idea of a sleek but rugged metal shell pavilion reminiscent of the clients’ car and Batman’s iconic kevlar suit.

As the house was in a greenbelt setting we had to balance the family’s space requirements and the footprint of the extension against the limits for volumetric increase.

Discussions with the planners were initially a little challenging as the existing house was originally permitted as an agricultural worker’s dwelling – a use which comes with many restrictions. Eventually, however, we were able to demonstrate the positive aspects of our approach and the planners agreed that breaking away from a traditional agricultural ‘look-and-feel’ was best for the site.

Explain the building’s outward appearance

We must have been really in tune with our clients, because they readily accepted what we saw as a bold initial concept. The extension that has been delivered retains the playfulness and originality of that initial concept.

To create the folded structure we had to simultaneously review the structural design and the arrangement of the zinc panels. We collaborated closely with a local craftsman through Stages 4 and 5 of the design and during construction. The zinc cladding provides a dramatic contrast to the red, mottled, handmade bricks of the existing house, but sits in harmony with the dark slate of the terrace. Slender-framed aluminium sliding doors fully retract to allow for views and direct access to the garden.

The project had a lot of elements that were difficult to forecast and needed extended collaboration to detail. The scheme was therefore procured on a cost plus management basis, which was an integral part of successfully delivering the building given its numerous complexities.

How were the interior spaces conceived, and how are they used?

The playfulness of the exterior is matched internally by an undulating roof plane tying together the kitchen area, a breakfast bar, a formal dining area and a corner nook currently hosting a pool table. As well as recessed aluminium strips, a triangular rooflight is folded into the roof level to introduce natural daylight into the deep plan.

Underfoot, large-format tiles help to smooth the transition between interior and exterior, and a projecting picture window provides a place to sit within the living space and take in the distant views over grazing pastures.

What was your approach to sustainability?

Making the home as sustainable as possible was really important to the clients and so the building fabric has been designed to be robust, airtight and incorporate high levels of insulation to ensure the living spaces remain at comfortable temperatures without high levels of heating and cooling. To mitigate solar gain, the extension is formed into canopies that oversail the glazed openings, especially those on the southern facade. The glass specification was also enhanced to reduce overheating and glare.

Internally the columns are exposed and painted rather than boxed out to minimise unnecessary material use.

The outdoor pool is heated by an air-source heat pump and as a holistic scheme the project transforms the once dark worker’s cottage into a modern family home.

What was the greatest challenge?

Finding craftsmen who were motivated and sufficiently skilled to handle the complexities of the project was our main challenge. Thankfully after a bit of a search we found a team who could be trusted to undertake the task, but given how good they were, they had limited availability which, of course, lengthened the build programme.

Due to the undulating roofline, providing a sealed waterproof layer on the roof was also quite difficult. Through our collaborations with the team at Install-zinc we were able to ensure the extension was perfectly sealed, but also looked well-finished from the outside.

Do you have a favourite detail or moment?

Our clients have told us how much they appreciate the way that the internal spaces connect into the outdoors and are filled with natural light, thanks to the floor-to-ceiling glazing.

I love the view of the extension when walking up from the garden swimming pool. Even though there’s a striking contrast between the existing house and the new pavilion, it just fits. Our design unfolds the structure and creates a unique and really irregular form that almost invites you inside. The space has real drama, with its undulating ceiling and the long-range views across the rural landscape.

James Hughes is founder and managing director of Fabric Design & Build

IN NUMBERS

Total contract cost £750,000-£1m
Area of extension 53m²