A study to identify how cob buildings in Devon and flint buildings in Norfolk are good examples of how 'the available materials are the principal dictators of style' in vernacular architecture.

University Degree Architecture, Building and Planning

A study to identify how cob buildings in Devon and flint buildings in Norfolk are good examples of how ‘the available materials are the principal dictators of style’ in vernacular architecture.

Throughout the counties of Great Britain, one can see styles of architecture which are unique to their region and are rarely found outside of it. ‘Such buildings, using local techniques and local materials, are said to be in the vernacular and are genuinely indigenous to their soil’. The reason for these regional differences is largely due to the geology of the landscape. The availability of different building materials in each region is the foundation of vernacular architecture. Infact

Regional buildings cannot be separated from their backgrounds, for to uproot a building style from the environment that created it would be meaningless and it is essential for a true appreciation of vernacular buildings to think of them in their proper physical context.

This essay looks at cob buildings in Devon and flint buildings in Norfolk, both of which are good examples of how ‘the available materials are the principal dictators of style’ in vernacular architecture.

The use of unbaked earth as a building material for permanent homes was quite widespread from around the late 15th century. Different methods of construction were used across Britain including clay bat and pise. Another method, particularly used in the West Country, was cob. Cob was essentially made up of earth which included clay, chalk, grit, silt and sand. This mixture was built up layer by layer, with each layer being left to dry before adding the next. To give the walling extra strength ‘large quantities of straw […] were mixed in to provide fibrous reinforcement and to minimise shrinkage cracks.’ Cob walls varied in colour depending on where the material was extracted. For example, the cob would be a red/pinky colour if extracted from the Permian Sandstones or grey if from the Culm Measures.

Cob building tended to be confined to the south western counties with most being situated in Devon. This confinement to a small area is because buildings are products of their environment. ‘Geologically the region is dominated by the huge granite bosses of Dartmoor and Bodmin Moor.’ Granite is a metamorphic rock that is extremely difficult to work with because it is too hard to shape. Also, at the time local resources were being used for building, the technology needed to quarry granite had not yet been developed. Although granite buildings do exist in this area, they are made up of loose moor stones of all different shapes and sizes. The land that Devon is situated on ‘gives rise to no very rich farming land and provides few building materials’ which meant there was little timber to build with. The lack of good building stone and timber led the Devonshire folk to use what they had and an abundance of; clay. The availability of clay was the not the only reason for building cob houses, the method was also economical. There were hardly any material costs and as the earth used was from near the building site, there were costs involved with transporting the material. Also it was a tradition in Devon for a bridegroom-to-be, aided by his future father-in-law, to build his wife a house. If this was the case, labour costs would also have been excluded.

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Flint buildings, like cob, are products of their environment. The use of flint as a building material was particularly in Norfolk. This was because ‘the chalklands of Norfolk, with their layer of boulder clay, provide nothing better to build with than rough flints from the surface of the land.’ There are variations in terms of the way flint is used in Norfolk. In the Breckland area of West Norfolk, the flints are halved to reveal their dark interior and used in walling with their dark side showing. Cobbles from the fields are used in northern and eastern Norfolk and along the coast, walls are made up of flint pebbles recovered from the beaches. However, although flint was readily available and had many decorative possibilities, it was difficult to build with due to its irregular shape and imperviousness nature. This led to the use of brick in flint buildings, providing corners and window and doorjambs.

Although transport was poor across Britain until the late 18th century, East Anglia had close contact with the Low Countries which where manufacturing bricks. The region became the first to import bricks into England and set up brickyards for local manufacture, which led to the wide use of bricks in domestic housing in the Norfolk area. Bricks were a particularly important component in flint buildings. Not only were they used to form corners, which was not practical with round flints, but were also inserted at intervals in order to absorb moisture which the flint was unable to do. To build the walls, the flint needed to be set in thick mortar which had to be of a correct mixture of lime and sand to aid moisture levels. In most walls the flint was laid uncoursed although the flint beach pebbles, which were more regular in size, were laid in neat courses. The walls were constructed in layers, with a drying time between each one to prevent the weight of mortar and flint causing the wall to slump. This process tended to cause the walls to bulge which is why in some buildings a line of bricks was added every two feet or so to prevent this from happening.

The process of building cob walls was actually quite similar to that of flint in that they were built in layers of around two to three feet at a time, again preventing the walls from slumping. However, whereas flint walls were made of two skins with rubble filling, cob walls were usually 20-24 inches thick. This enabled the walls to support themselves rather than having to be built around a skeleton of timber or stone. As with flint, the builders of cob houses had a problem when faced with corners. Although it was fairly easy to achieve corners with cob, the nature of it meant right-angled corners were vulnerable in terms of structural capabilities and also the weather. To solve this problem, cob houses were built with round corners ‘to reduce the danger of abrasion or crumbling.’ To give extra protection to the cob, a layer of roughcast was applied and then a final layer of lime plaster or white wash.

A well known Devonshire proverb claims that ‘all cob wants is a good hat and a good pair of shoes’, which is exactly what a well made cob house was given. ‘A good pair of shoes’ refers to the use of a stone plinth as a foundation for cob. This was usually made up of blocks of moor stone, stood at around two and a half feet high and covered with tar. By building this foundation, damp from the ground was prevented from reaching the cob and also vermin were unable to tunnel their way into the house. As for the ‘good hat’, this referred to the need for a well made roof. The roofing used for cob buildings is similar to that used on early flint building in that they were both thatched. Roofs were pitched at no less than sixty percent ‘to ensure that rainwater ran off the thatch as quickly as possible.’ Also, the thatch needed to have large eaves so that rainwater would run straight off onto the ground and not damage the walls by soaking them. The weather also affected the shape of the roof in another way. The West Country, not being as windy as East Anglia, was able to make thatches with rounded corners which literally looked like hats. This added to the general rounded look of the cob house. Thatching was the ideal material for cob as anything heavier such as slate would have put too much pressure on the walls. However, extra support was sometimes needed for the roof and so from around the 15th century, raised crucks were added to the gable end. The thatch itself was made of unthreshed wheat and was usually soaked in water and alum, which made it easier to lay and also reduced the risk of fire.

The Norfolk thatch was made not with wheat but instead from the very durable reds from the marshy fens. Because of the winds from the North Sea, Norfolk flint buildings would be in danger of having their thatch blown away if it were rounded like that of cob. Instead, flint houses were built with high gable ends to offer some protection from the wind and also give a greater grip to the thatch. However, from the 17th century, East Anglia was receiving pan tiles from the Netherlands. These were S-shaped tiles, red in colour which formed ‘channels that allowed the rainwater to run down the roof into the troughs along the eaves.’ The thatch was soon replaced and it is the pantiles that Norfolk houses are mostly associated with. The use of the tiles was just another feature of the Dutch influence in Norfolk architecture which also included crow stepped and the curvy Dutch gables.

The position of the windows separates cob and flint buildings. The windows of the cob house, and infact like most others, were recessed into the walls. This offered protection against the weather especially the rain which the West Country gets plenty of. A line of tiles was often added to the window ledges to protect the walling against the rain. In the flint building, windows were placed forwards so they were flush with the brick. Although this offered little protection to those indoors, it did create large windowsills ideal for displaying trinkets.

The placement of the chimney differs also. Although most early houses had a central hearth, the building of chimney stacks later on offered the chance to create regional variations. The Norfolk farmhouse had back to back fireplaces in a central position, providing warmth to both the downstairs rooms. It is also common to find the chimney stacks at both of the gable ends. The Devonshire people however, were much more proud of their chimney stacks and displayed them at the front of the house. Another feature the Devon farmhouse had was a wide through passage. Explanations for why the passage was so wide include; the farmers oxen, with its wide body and spread horns, had to pass through the house via the passage and to fit through, the passage had to be exceptionally wide. Another suggestion is that large cider barrels were rolled through the passage.

By studying buildings that have stood the test of time, it is possible to see how each region had its own architectural accent. Devon cob and Norfolk flint are just two examples out of many showing how the materials used differed because the same materials were not available in every region. In all areas it is possible to see how the wealth of the local economy could also affect building styles. The building techniques were naturally varied across Britain, as locals tried to use the materials to their best advantage. However, many things can be found to be similar even in buildings from one end of the country to another. One thing vernacular buildings all certainly have in common is that they eventually stopped being built towards the 18th century as Britain began to embrace a new, national style of architecture.