The renovation of this cob barn adds another layer of history to a building that has been expanded and stitched together over the last two hundred years. The project celebrates the rich patchwork of materials comprising of cob, stone, concrete and brick. Keeping much of the existing fabric, the project sought to insert a new load-bearing timber frame within creating further distinction between old and new constructions. The use of cob, made up of material excavated on site, grounds the building on the site and results in a tonally subtle and contextual response. Over time the cob is weathered to reflect the prevailing wind direction, similar to the arching wind-blown trees. This barn required a robust strategy to cope with the wild coastal weather blowing in from the Atlantic, hence the deep eaves and sunken courtyard spaces. Sunlight plays on the rough cob and masonry textures, while stark shadows are cast against the more refined clerestory reveals and crisp pre-cast concrete window surrounds.
The strategy is based on keeping much of the existing fabric while inserting a new load-bearing timber frame inside. In order to avoid excessive underpinning, the foundations are set inbound of the existing walls with a cantilevered slab picking up the load of the the timber frame. Larch fins support the load of the roof above the inserted load-bearing structure.
The tapering plan and section is a result of the form set out by the masonry barn and gently rising slope with the cranked kitchen space enclosing the external space for more private use. The shifting walls, in turn impacts on the roof form, resulting in rising eaves to allow for a consistent ridge line and planar roofs. These historic influences on the form create a variety of subtly different spaces and aspects.
The original 18C barn was constructed in masonry stone walling, then considerably extended using cob construction. Cob blocks were used to patch the walls and extend the western gable end before being finished with a flick-coat. For more recent agricultural use, concrete lintels and blockwork were used to patch the building, a technique referenced in the crisp pre-cast concrete surrounds used for the new windows, while the slender timber fins support the roof and contrast with the heavy cob and masonry outer walls.
The thick cob walls offer some thermal mass, and combined with the insulated timber frame internally, creates a highly insulated building, shielded from external temperature fluctuations. The whole site complex is heated using a ground-source heat pump serving the main farmhouse and two barns. The cob barn is also fitted with a central wood burner for peak winter periods. Where possible, reclaimed materials were used, for example in the slates, oak floorboards and cob material reclaimed from a derelict cob shed.