Grand Designs Blackdown Hills

Inside the Devon ‘spiral home’

This memorable self-build took inspiration from natural instances of the golden ratio

By Jayne Dowle |

One small object set Stephen and Elizabeth Tetlow on a path that led to the design of Oat Errish Farm in the Blackdown Hills, an Area of Outstanding Natural Beauty near Taunton, on the border of Devon and Somerset. This unique spiral house, also known as the ‘fossil house’ or ‘snake house’, first featured on Grand Designs in 2017 and has a close connection with its idyllic surroundings.

‘The inspiration for the shape came from an ammonite fossil that we had on our dining room table,’ explains Stephen. ‘The building is shaped in what is known as the golden ratio in both plan and section. There is found many times its found in nature too, such as in the spiral patterns in pinecones and the fronds of a fern. So, the idea was to design our home to reflect the nature around it.’

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Photo: Fraser Marr

In tune with its surroundings

Prior to this, Stephen and Elizabeth lived in a nearby thatched cottage for a decade with 8 acres of land. When the couple decided to take the plunge and embark upon building their own house, they sold their cottage, retained most of the land for the plot and named their new home Oat Errish Farm, after the field in which it is built, as described on the tithe map of 1844.

The property reflects the undulating rural landscape it sits in; although strikingly modern, it is never at odds with the hills and fields all around. Stephen suggests this has been achieved through close collaboration with the architectural firm, Sadler Brown, and the planning consultant, James Ellis from Rural Solutions, who provided invaluable guidance. East Devon District Council’s Planning Committee passed the plans unanimously at a public hearing.

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Photo: Fraser Marr

On site every day

Some of the exterior walls are faced in chert, a local stone, while the oak windows and doors are bespoke and locally made. The roof is clad in textured wooden panels, made from an incredible 4,600 separate slats, comprising a mixture of redwood cedar, Siberian and English larch mounted on green oak runners.

Elizabeth stayed in Devon as de facto project manager while Stephen worked in London: ‘One of us was on site every day, which was essential in order to know exactly what was happening, run errands, answer questions and chase deliveries. We also went to our local recycling site often, as the rubbish built up quickly.’

The couple have three grown-up daughters and four grandchildren who often visit, and although their home represents the pinnacle of Stephen’s fascination with combining scientific principles with design, it is very much a family home. ‘A key part of our plan was for the house to be a welcoming place with enough bedrooms for our children and grandchildren to come to stay together,’ says Elizabeth. ‘The large open-plan living space is a wonderful area for running around.’

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Photo: Fraser Marr

An upside down house

The property is ‘upside down’, in that most of the bedrooms are on the ground floor and the living areas are on the first. This space is where form and function come perfectly together to create a huge open-plan area encompassing kitchen, seating and relaxing.

The ceiling soars, held aloft by the exposed curved glulams (glued and laminated beams), create the backbone of the house. These are made from English larch grown  in Devon and Cornwall and manufactured off-site to precise golden ratio measurements.

‘Living in a curving house seems to create a calming and harmonious balance,’ says Stephen. ‘It is a truly amazing place. The quality of the light and the view from each window is glorious. Our home has a real sense of place and a wonderful connection with the fields and meadows.’


Project finished November 2017
Size 247 sq m
Build cost £800,000
Architect Sadler Brown
Landscaping Alistair W Baldwin
Planning consultant Rural Solutions
Builder Jason Turner
Glulams Buckland Timber
Joists Donaldson Timber Engineering
Oak windows Brendan Wellman
Glass Topline
Copper cladding Zincworks Roofing

Watch the Blackdown Hills episode of Grand Designs from 2017