The architect James Wyman has designed and built a small live-work studio in an Oxford garden. It is distinguished by the careful detailing of its timber elements, winning the Small Projects category of the Wood Awards in 2014.

Sweet chestnut is the principal timber used, chosen for its inherent natural beauty of colour and texture but also for its sustainable qualities: FSC certified sweet chestnut could be sourced and manufactured locally. The studio is on the site of a former garage of a large Edwardian house on the Woodstock Road, Oxford.

The house had long ago been divided into flats and the garage, set on the boundary wall, had been converted into a one-bedroom flat with a small patio. It was small – less than 3 metres wide – with a solid brick wall construction which encouraged damp to penetrate. But it benefited from an attractive setting, looking out over a communal swimming pool and large garden with mature trees and an attractive Victorian glasshouse.

James Wyman bought the garage flat and negotiated with the management company of the main house to permit him to build an extension at the rear. To assuage concern that the extension might block the view of the pool from upper windows, the pitched roof of the extension is glazed. The double pitched roof and open form of the new studio extension reflects the surrounding buildings, especially the nearby Victorian glasshouse, which helps to integrate it with the garden setting. But to the architect it was equally important to create a comfortable and healthy interior environment, to improve the existing damp and humid flat with the use of more appropriate and sustainable construction techniques, and in particular, products which were local.

As James Wyman explains:

“With this slightly optimistic challenge in mind we set about sourcing appropriate materials and manufacturers, initially just to gauge how difficult the task ahead might be. At the outset the choice of timber had a wide appeal as the embodied energy contained within a timber structure is significantly less than that of steel or concrete. So simply by choosing timber construction we established significant environmental benefits. To my mind the most important of these benefits is that wood is a renewable material unlike the majority of other construction materials.”

The choice of manufacturer was also important as most glue-laminated materials used in the UK are imported from Europe. Inwood Developments, based near Lewes in East Sussex, were chosen for their ability to manufacture high quality timber engineering and cladding components.

The original single-storey building has been transformed by the careful use of timber. The end wall has been clad with vertical hardwood slats. Inside, the original walls have been lined with hemp and lime insulation and the partitions which form the bathroom, store and kitchen have been clad with vertical sweet chestnut boards, rough-sawn to relate to the simple aesthetic of the original outbuilding and the other materials used: stock engineering bricks and power-floated concrete floor. The partitions stop short of the ceiling to reveal the original timber-boarded pitched roof. Hemp and lime were used not only to insulate the masonry and to offer additional thermal mass, but also to provide a breathable form of construction which helps to regulate internal humidity levels.

The new studio extension is a single open plan space roofed with two pitched bays, both glazed between the rafters with ‘heat mirror’ insulated glass units. The bays are divided by a metre-wide flat roof valley, from which rises the chimney of a large freestanding wood burning stove. The double-sided stove is clad in Cor-Ten weathering steel and punctuates the otherwise open plan. The roof structure, windows, doors and wall panelling are all made of sweet chestnut. The side wall has a sweet chestnut frame containing a row of centrally pivoting triple glazed windows to provide natural ventilation to the studio.