cob house grand designs

The Cob House: a sustainable castle in Devon

This giant cob castle took nine years to complete. But was it worth it?

By Gemma Parkes | 31 October 2018

In the last episode of the 2018 series, Kevin McCloud returned to the Grand Designs cob house to meet Kevin McCabe, the man who wanted to build one of the biggest houses in Grand Designs history. McCabe took a vow that his build would meet the highest standards of sustainability. He also declared that he would build most of it with his bare hands – out of mud.

He is known as ‘the king of cob’, but building his cob castle in the East Devon countryside presented McCabe with the greatest challenge of his life. During the nine years it took to complete the gargantuan 1,250 square-metre cob house, McCabe’s marriage of 30 years ended in divorce. He also found himself living in a caravan and borrowing money from friends to meet his financial obligations.

In the face of masterminding the building of Dingle Dell, a modern manor house inspired by the work of Spanish architect Gaudi and South American earth homes, some men would have crumbled. But not 56-year-old Kevin, whose demeanour belies decades of hard graft and ambition.

East Devon cob house from the 2018 series of Grand Designs

A series of shaded sunspaces with thermostatically controlled windows creates a glazed roof link between the main house and annex. Photo: Mark Bolton

Problem solver

‘I am very resilient and when a problem comes up, there is always a way around it,’ McCabe says. The Grand Designs cob house includes a 650 square-metre main house with four bedrooms and six bathrooms. There’s also a kitchen-dining room, living room, utility, cloakroom, study, gym, games room, plant room, two sunspaces and a greenhouse. Not forgetting the 150 square-metre annex with three bedrooms, two bathrooms, two living rooms, a kitchen, sunspace, cider shed and a workshop. However, this massive project was not without its problems.

Outside of Grand Designs Cob House with floor to ceiling windows

With its curved cob walls, the lower level is sunk into the hillside. Photo: Mark Bolton

Cob house challenges

Cob (a mixture of clay, straw, sand and water) has its own challenges as a building material. First used more than 10,000 years ago, cob is renowned as the most sustainable building material ever devised. During the build, international experts and practitioners came along to assist and study the master at work.

Kevin regards it as ‘a very sculptural material, enabling unique and beautiful forms’, such as the staircase that winds through the middle of the main house. However, each ‘lift’ of cob must be moulded into shape manually and requires long hours of warm, dry weather to set firmly. This, unfortunately, is a requirement that can’t always be guaranteed in Britain.

Using cob on such a large scale (the walls are three-feet thick) had never been attempted before in this country. However, the mechanics of the job did not deter Kevin, in spite of the rainy summer of 2012. He set about drafting in his trusty band of workers to erect the walls and dig the foundations, which run for more than a quarter of a mile.

Wooden drawbridge pathway leading to main entrance with wooden archway of Grand Designs cob house

The house is accessed by a wooden bridge that leads to the entrance hall. Photo: Mark Bolton

Financial struggles

It was the financial aspect that presented the greatest hurdle. In 2013, Kevin’s original budget of £350,000, raised by borrowing against his existing home – also a cob-build, which he had shared with his former wife, Rose – had run out. The couple decided to put the home up for sale, but the first offer was withdrawn. Not long afterwards, Kevin and Rose split up and then divorced.

After almost three years of work, not a single room in the new house was habitable. Progress faltered as Kevin struggled to combine finishing his project with the need to earn some money. ‘All the proceeds from the eventual sale of the original home went to the divorce settlement,’ Kevin explains. ‘And to my surprise, because I’d been working on Dingle Dell for three years, I discovered that my business had not made a profit, which meant I couldn’t borrow from any banks. In fact, I found myself needing to borrow from friends.’

Cob fireplace with brown leather sofa, wooden coffee table decorated with vibrant bouquet and blue striped rug

The living room features a twin log store on either side of the cob fireplace. Photo: Mark Bolton