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Devons own cob castle.

Dingle Dell has attracted the attention of the world. Builders and the public alike are following the build of what has been identified as Europes most significant cob building with bated breath.Dingle Dell is a Devon mans dream coming into fruition. Kevin McCabes skills are now world renowned ; but still not content that he had reached the pinnacle of what he could achieve, he decided to embark on this truly astounding project. He is doing so under the watchful eye of the media. Grand Designs, a British programme that follows some innovative and unusual builds and renovations, is making the journey with him.

Introduction

Truro

Exeter

Ottery St Mary

Dingle Dell

Key dates :Planning permission : March 2010.Build : 2011 expected finish 2015.

Exterior - Photo Servane Guihaire - Constructys Bretagne

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Kevins aim is to build a family house, whilst testing the limitations of low impact materials and endeavouring to use some of the Passive House standards to try to achieve CODE Level 6 accreditation. He is using over 30 years of experience to help him achieve this ambitious project. He would like the building to be a showcase for British architecture and so he applied for planning permission under previous legislation, Planning Policy Statement 7, which allows exceptions to normal planning policy for sustainable development in rural areas. To gain this, the design had to be outstanding, innovative and ground-breaking in its use of

Contextmaterials or methods of construction. To help him work towards this aim Kevin worked with several different architects and professionals across the construction spectrum including structural engineers, renewable technologies experts, drainage experts, an ecologist, and local planners. Ultimately, Dingle Dells palatial size and sweeping curves of cob and glass combine the traditional with the modern aesthetic, and is a worthy of the special permission granted.Kevins dedication to the project is demonstrated by the fact that he has worked 70 hours a week over the past

Plan Kevin McCabe

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three summers to try and achieve his goal, making the most of what good weather he could, although an extraordinary amount of rain in 2013 - 2014 hampered his efforts.

Dingle Dell is to be 10,000 sqft, double the size of Kevins current home. The building will comprise of two cob roundhouses. The larger of these will be over three floors and will be the familys main living space with a music room and games room

in the basement. The smaller will be a self-contained living space for guests, with the basement used for storage and a cider press! The two are joined with an enclosed glass walkway with a fully functional greenhouse in the middle.

The building of Dingle Dell commenced in spring 2011 by excavating 5,000 tonnes of soil, this not only made way for foundations but provided the main material

Building overview

Exterior - Photo Servane Guihaire - Constructys Bretagne

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needed to make the cob. The trench system foundations for walls stretch for of a mile and are filled with eco concrete, with a reduced cement content by using by-product from coal fired power stations, and topped with a mixture of lightweight concrete blocks. The cob was laid on the block base in lifts to create the enormous walls. The centres of the roundhouses have circular enclosures housing helical staircases, and the outer cob walls are also wrapped in polystyrene for added insulation and covered with lime render.

The structural strength for the roofing is provided by using Glulam beams. 12 x 9 m lengths were used for the main roof and were cut in a mixture

of concave, convex and straight to create the undulating, organic shape intended to blend effortlessly with the surrounding hills. The roof will be covered in polystyrene to create an insulating waterproof base for the planted meadow finish.Kevins heating is via a heat recovery system with approximately 700 sq m of underfloor heating. Approximately 200 sq m is not heated, but a significant factor for this, is the fact that cob acts as a thermal store.

The power is provided by a 10 kW Photovoltaic array which was installed on the barn roof prior to the government deadline in

Exterior - Photo Servane Guihaire - Constructys Bretagne

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December 2011, so that Kevin could take advantage of the feed in tariff available at the time.

What is evident about this build is that Kevin has pushed the limits of both design and the use of materials to the extreme, working in an experimental but intelligent fashion. His love of building with cob and its sculptural

Technical focus: Using Cob Pillars

nature and strength has encouraged him to push the boundaries. Not many would think to make pillars from cob. Kevin used pillars in building the barn and also for the walkway of the main house.The supporting pillars for the main houses walkway are 550 mm in diameter and the tallest is 5 m high. The construction of the pillars was done in the same way as the walls. The foundations were put down to stable ground, and then filled with a concrete base, upon which the plinths were built from natural stonework. The cob is made from clay, straw,

Interior - Photo Servane Guihaire - Constructys Bretagne

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sand and water to bind the materials together, then, placed on these round plinths in lifts in the same way as a cob wall is constructed. However, the lifts for the columns were smaller, only 300 mm, and were done using a mould to keep the shape and then finished by hand.

Each cob pillar is holding up several tonnes. The cob can cope with this as it is compressively strong but prior

to the build testing was done by engineers. During testing for the cob pillars, the cob withstood a force of 1.6 newtons, the engineer then used a figure of 1.1 N for build calculations. Once built, before any load bearing was allowed to take place, the pillars were checked on site by his structural engineer, Barry Honeysett.

Exterior- Photo Servane Guihaire - Constructys Bretagne

Cross section Kevin McCabe

The building process for Dingle Dell has not been as straight forward as Kevin would have liked. He has been hampered by the weather. In 2012, Devon had the wettest summer for

Barriers and solutions

StakeholdersClient : Rose and Kevin McCabeBuilder : Kevin McCabe www.buildsomethingbeautiful.com Architects : Bedford & Jobson www.architecturedevon.co.uk

Costs Kevin says that the cost of the build will eventually be around 500,000, although this does not take into account his own labour and using cob from the site which would more than double this figure, bringing it closer to a million. Before building, Kevin had already paid 30,000 to architects, 30,000 for engineers, and 50,000 on modelling before planning permission was given. Building your own cob castle is not cheap. They say an Englishmans home is his castle, and in Kevins case, he really will have one.

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100 years, and this severely restricted the ability to build with cob. The prolonged period of the build meant that money became an issue, so Kevin had to go back to work on paid projects to fund the further development.

Interior - Photo Servane Guihaire - Constructys Bretagne

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