Kevin McCloud returned to Devon for one of the most anticipated revisits in Grand Designs TV history in final episode of the 2018 series. Look inside Kevin McCabe's finished cob castle and its sustainable features.

East Devon cob house from the 2018 series of Grand Designs

Image: Mark Bolton

The last episode of the 2018 series of Grand Designs' saw Kevin McCloud return to Devon to meet Kevin McCabe, the man who wanted to build one of the biggest houses Grand Designs has ever seen. McCabe vowed that his build would meet the highest standards of sustainability and that he would build most of it with his bare hands – out of mud. Finally, seven years after it began, the herculean task of building this giant cob castle is complete.

Back in 2011, Kevin McCabe didn’t just want to build just a cob house – he wanted to build a cob castle measuring an enormous 10,000 square feet. The house was to be formed of two vast curved cob roundhouses connected by glazing and topped with undulating wild-flower meadow roofs to mirror the surrounding countryside.

The build involved mixing and laying 2000 tonnes of cob, all during warm sunny weather so it could dry rock solid. But Kevin was hit repeatedly by some of the wettest weather on record, and despite pushing cob to the very limit of its capacity, the money eventually ran out and the project ground to a halt.

When Kevin McCloud last visited in 2013, the only complete feature of the house was the verdant green roof. The rest of the building was muddy, exposed to the elements and uninhabited. However it’s now 5 years later, long enough for Kevin McCabe’s life to have changed unrecognizably, but also long enough for him to have finally finished his vast cob castle.

Here are just a few of the sustainable ideas Kevin McCabe has incorporated in his cob castle - which you could try yourself. 

Handmade cob and timber cupboards

East Devon cob house kitchen feature on the 2018 series of Grand Designs

Image: Mark Bolton

Kitchen cupboards were handmade from cob and timber by Kevin, who added the chunky oak worksurfaces.

Recycled glass and birch tree light fittings

Light fitting made from recycled glass bottles and birch in the Devon cob house featured in the 2018 series of Grand Designs

Image: Mark Bolton

Suspended from the ceiling, this quirky light fitting was made by Kevin from a single piece of birch and hung with the recycled bottles as shades.

Cob fireplace

East Devon cob house living room with fireplace featured in the 2018 series of grand designs

Image: Mark Bolton

The sweeping living room features a twin log store on either side of the cob fireplace. Sinuous curves create a counterpoint to the perpendicular beam.

‘Properly built and correctly maintained, cob is by far the most comfortable material to live in as it regulates heat and humidity naturally,’ says Kevin. ‘It couldn’t be more environmentally friendly; it’s made from the local environment and at the end of its life, which could be a thousand years or more, it can meld back into the soil, or be re-used as new cob.

Cob and oak staircase

Devon cob castle staircase from the 2018 series Grand Designs

Image: Mark Bolton

Curvaceous and sculptural, the cob staircase was inspired by the shape of a snail’s shell and winds up through the centre of the house.

‘We had time to let ideas evolve and to create elements such as the earth floor and the cob and oak staircase’, says Kevin.

Thermostatically controlled windows

Devon cob house with green house from the 2018 series of Grand Designs

Image: Mark Bolton

A series of shaded sunspaces with automatic thermostatically controlled windows creates a glazed roof link between the main house and annex. A greenhouse sits in the middle.

Set into the thick walls of the two buildings that make up the house is a series of huge window frames, each of which is triple-glazed, and within the glazed link sits a greenhouse, where Kevin grows tomatoes. Each building has a wildflower meadow on its roof, a softly angled design that mirrors the wavy lines of the surrounding hills. To meet stringent regulations, walls were insulated with polystyrene – 100 per cent recyclable and A+ rated for sustainability – and rendered with lime.

Thanks to a range of energy-saving measures including solar panels to heat the water, pipework and butts to harvest rainwater, and a borehole for the cold water system, the house produces more energy than it consumes.


What are your favourite features of Kevin McCabe's cob house? Tweet us @granddesignsmag or post a comment on our Facebook page



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