Proof of principle
Words by Jamie Crocker
VESP’s new office puts its architectural principles into everyday practice. A building designed by architects inevitably says something about its occupants, but VESP Architects’ new office in Ashburton goes further: it is a working demonstration of the ideas the practice has spent two decades developing for its clients. Designed and built for themselves, the Passivhaus office gives those principles a daily test.
The practice had reached the limits of its previous premises, one of Ashburton’s converted Brunel railway buildings. It was cold in winter, hot in summer and short on useful meeting space, while the practice itself had grown. The original plan was to rent a new commercial unit being developed nearby, but when that arrangement fell through, the developer offered VESP the chance to buy a plot and build its own office. That changed the proposition completely. The practice could design a building around the way it actually worked, with room to accommodate future growth.
The result is a simple, single-storey rectangular building organised around a large central studio. Meeting rooms and supporting spaces sit to either side, keeping circulation to a minimum and allowing the main workspace to remain open. There are currently 12 people in the practice, while the studio has capacity for considerably more. The arrangement encourages colleagues to see and speak to one another, and gives each person a direct relationship with the wider working space.
That openness is carried into the building’s relationship with daylight and the landscape. Large areas of triple glazing bring natural light deep into the studio and provide views towards the trees beyond the car park. Although triple-glazed, the windows still presented the weakest point in the thermal envelope, so additional insulation was incorporated into the walls, floor and roof to compensate. A shallow-pitched zinc roof projects beyond the façade, creating overhangs that help control solar gain, while three rooflights bring daylight further into the plan and assist natural ventilation.
The construction is similarly straightforward in principle, though carefully resolved in detail. An insulated raft foundation supports a timber-frame superstructure, while the wall and roof envelope uses twin timber studs connected with plywood fins. The 400mm cavity is filled with Warmcel blown cellulose insulation, made from recycled newspaper. Internally, the construction achieves an airtightness of 0.29ach; twice as good as the passive house requirement. Even the concrete slab has been asked to earn its place: sitting within the thermal envelope, it forms the structural floor while acting as a thermal ‘heat-sink’. Ground and polished, it provides a beautiful finished surface, removing the need for another flooring material.
The choice of timber for the external cladding carries another piece of the practice’s thinking. VESP worked with a nearby supplier using ash affected by ash dieback, thermally modifying the timber to create a durable cladding material from a resource that might otherwise be wasted. The treatment also gives the ash a darker appearance, while the exposed timber will gradually silver with weathering. Six to eight months after occupation, that process was already visible on the more sun-exposed elevations. There is a useful honesty in VESP’s description of the material choices because the practice does not claim that every decision represents the absolute endpoint of sustainable construction. The directors acknowledge that building from scratch carries a greater carbon burden than converting an existing structure. Their argument rests on the building’s operational performance and on the relatively low-carbon construction system used once the decision to build had been made. The building structure is timber, which is a natural ‘carbon sink,’ balancing the concrete slab, which remains an unavoidable carbon cost.
That admission matters because sustainability in architecture can easily become a matter of labels. Passivhaus certification provides measurable standards, but a genuinely responsible building also requires decisions about materials, longevity and how a building behaves once the photographs have been taken. VESP is now in the useful position of having to live with those decisions every working day.
The building’s performance so far has been encouraging. Its mechanical ventilation and heat recovery system serves a 14-person office and incorporates an integrated heat pump, providing the sole source of heating and cooling. In winter, the occupants, computers and solar gain contribute enough warmth that the heating has barely been needed. After the office closes for the three-day weekend, the internal temperature can fall only a few degrees before rising again once the team returns
That is perhaps where the office becomes most interesting. It is an experiment with consequences. VESP can see what works, what needs refinement and how occupants actually behave within the spaces it has designed. The practice is continuing to monitor the building’s in-use performance with its Passivhaus certifiers, Warm, and intends to use the office as a place where local architectural and sustainable construction groups can learn from the project.
Inside, the environmental ambitions have been matched by a desire to make the place pleasant to occupy. There are two substantial meeting rooms, a kitchen and breakout area, glass partitions that preserve visual connections between spaces, and a polished concrete floor that has already become a talking point with visiting clients. The kitchen was produced with local companies, alongside other elements of the interior. The intention was to create an office that feels domestic enough to be comfortable, while still functioning as a serious professional workplace.
The social dimension is important, too. VESP operates a four-day working week, with Fridays free to enjoy their Devon location. The new office has been designed around a collaborative studio culture, where flexibility allows the team to work together to achieve the best outcomes. Its generous shared spaces give the arrangement physical form, while the kitchen has proved particularly successful: at lunchtime, people actually gather there, talk and take an hour away from their desks.
For a practice whose portfolio is largely focused on high-end private houses, the new office serves as a full-scale demonstration project. Clients can experience the window systems, see the timber construction and examine the polished structural slab. Materials that might once have been discussed through drawings and specifications can now be encountered in person. The architects are living inside their own argument.
VESP’s new studio is the practice’s clearest statement of intent. Every surface, sightline and material choice was considered exactly as it would be for a client. Light moves through the space with purpose, softening over timber and stone, shaping workspaces. It is a designed to welcome clients, contractors and other collaborators into an environment that reflects how the team thinks and works together. More than an office, the building acts as a signpost: a physical demonstration of VESP’s values and the talent that lies behind every project they take on.
That makes the new VESP office a useful advertisement for the practice, but also something more demanding: a building that has to prove its principles every day. Its success will ultimately be measured through use, performance and durability, not simply through the language attached to its construction. VESP has given itself the most exacting client it could have chosen, because every decision accompanies them to work each morning.
