Cob cottages were built mainly from earth, straw and water. Their walls needed no brick kiln. Much of the material could come from close to the building site.

For localism, this makes cob worth reconsidering. It offers an example of housing shaped by local resources, practical knowledge and human labour. Modern Building Regulations allow this approach in England, but a new cob cottage must demonstrate that it is safe, durable and sufficiently energy-efficient.

What were cob cottages made of?

Traditional cob used subsoil containing clay, mixed with sand, small stones or other suitable aggregate, straw and water. The clay bound the mixture together. The aggregate helped control shrinkage, while the straw reinforced it.

The proportions depended on the earth available. There was no single recipe suitable for every locality. Builders used mineral subsoil rather than fertile topsoil containing roots and other organic matter.

Animal dung sometimes appeared in historical mixtures. It was not essential. Its presence may sometimes have resulted from cattle treading the material during mixing.

Cob is particularly associated with Devon and the South-West. Related earth-building traditions include clom in west Wales, clay dabbins in Cumbria and wychert in Buckinghamshire. Their differences reflected local materials and experience.

How were they built?

Builders thoroughly mixed the earth, water and straw. People or animals could tread the mixture to combine it.

In mass cob construction, the material was placed directly onto the wall in successive layers, often called lifts. Each lift needed time to firm up before more weight was added. The wall faces were trimmed to shape.

Clay-lump construction used a different method. Earth was moulded into blocks, dried and then laid as walling. Neither method required firing in a kiln.

A complete cottage still needed other materials. Masonry formed the protective base. Timber supplied roof members, floors, doors and window frames. Roof coverings could include thatch, slate or tiles.

Keeping the walls dry

Earth walls need protection from excessive water.

Traditional cottages commonly had raised masonry bases and generous roof overhangs. The base reduced contact with ground moisture and rain splash. The roof sheltered the wall faces. Good drainage and sound roof coverings were essential.

Lime or earth finishes could protect the walls while allowing them to dry. Inappropriate cement render and waterproof coatings can trap moisture and cause deterioration. Properly maintained earth buildings can survive for centuries.

Their survival shows that earth can be durable. It also shows the importance of suitable design and maintenance.

Do current Building Regulations allow cob?

Yes. In England, Building Regulations do not require every house to be made from brick, concrete block or another standard manufactured product.

Approved Document 7 explains that the solutions described in the government’s guidance are not exclusive. Other materials can be suitable. What matters is whether the materials and workmanship perform adequately in the circumstances in which they are used.

This provides a route for cob construction. It does not mean that any mixture of earth and straw will be acceptable. The suitability of the material and the design must be demonstrated.

A new cob cottage must meet the relevant requirements for the whole dwelling. These include structural stability, fire safety, resistance to moisture, ventilation, energy efficiency, drainage and access. Cob walls are only one part of that assessment.

The practical approach is to involve building control early, supported by a designer and structural engineer with experience of earth construction. Evidence may include soil and material tests, structural calculations, moisture details and energy calculations.

Planning permission is a separate matter. An acceptable construction method does not establish a right to build a house on a particular piece of land.

The energy-efficiency challenge

The earlier claim that thick cob walls make a comfortable house needs qualification.

Earth walls can store heat and release it slowly. This can moderate temperature changes. However, heat storage and insulation are different properties. A traditional cob wall cannot simply be assumed to meet the standards required of a new dwelling.

The design may need additional insulation or an earth construction system developed to provide better thermal performance. Any insulation must also be compatible with the wall’s moisture behaviour.

Roof insulation, windows, airtightness, ventilation and heating all contribute to the result. A local material can therefore be combined with modern design to produce a comfortable home.

The rules also continue to develop. England has published new energy and ventilation guidance for the Future Homes and Buildings Standards. The associated regulations generally come into force on 24 March 2027, subject to transitional arrangements. A proposed project must establish which requirements apply to it.

Why cob matters to localism

Brickmaking requires fuel for firing. Cob avoids that stage. Where suitable earth is available nearby, it can also reduce the movement of heavy walling materials.

The localism argument follows from these practical differences. As energy and transport become more expensive, methods using nearby resources may become more attractive.

Cob could support connected local occupations. These include earth building, carpentry, lime plastering, roof maintenance and the supply of straw and timber. Skills would remain within the locality, alongside the ability to repair what had been built.

This would replace some dependence on industrial production with greater dependence on skilled labour. It could provide useful employment for people moving from discretionary work into the provision of essentials.

Could cob become affordable housing?

Possibly, but cheap earth does not automatically produce a cheap house.

Cob construction requires labour, drying time and suitable weather. Testing, design, foundations, roofing, services and regulatory compliance still cost money. Additional insulation may also be necessary.

Affordability would depend on the site, the design, access to skilled workers and how the work was organised. Local training and repeated use of well-developed designs could help.

A sensible beginning would be to repair existing earth buildings, train builders and construct demonstration projects. Experience could then support new homes.

Cob is a practical possibility within modern building rules. Its contribution to localism would come from combining nearby materials and skilled hands with homes that are safe, dry, comfortable and economical to run.

A locality needs the means to maintain its buildings. Houses, workshops, food stores and agricultural buildings all require repair. Some new buildings will also be needed, even in a shrinking economy.

Local brickmaking could provide part of that essential capacity. It brings together a natural resource, skilled labour and a durable product. Where suitable clay and an affordable source of heat are available, a brickworks could serve several neighbouring localities.

The starting point should be the preservation of existing works and their knowledge. Establishing a new brickworks becomes much harder if the people who understand clay preparation, drying and firing have disappeared.

Examples which survive

Northcot Brick at Blockley in Gloucestershire uses clay from its own quarry. It retains handmade brickmaking alongside machine production. The works was established in 1925 partly to provide housing and employment for local people. That original purpose has a clear connection with localism.

H.G. Matthews, near Chesham in Buckinghamshire, produces handmade wood-fired bricks. It also uses woodchip to provide heat for drying. Its experience offers a practical connection between brickmaking and a wood economy.

Bulmer Brick & Tile, near Sudbury, is a small family business using clay from its own seams. Its specialised bricks support the repair of existing buildings. York Handmade Brick at Alne in North Yorkshire provides another example of an independent manufacturer with a brickworks and quarry site.

These businesses demonstrate that the skills survive. They do not establish that every locality could produce cheap bricks. Their methods, fuel requirements and costs would need careful examination.

Repair before expansion

In a shrinking economy, the purpose of a local brickworks would increasingly be to maintain useful buildings.

Repairing a wall or extending a workshop may require relatively few bricks. Matching older brick sizes and shapes can be especially valuable. A small works could develop its business around these needs.

Reclamation could form a complementary activity. Suitable bricks recovered from demolition could be sorted, assessed and offered for reuse. New bricks would fill the gaps which reclaimed supplies cannot meet.

Reclaimed bricks still need assessment for their intended use. Their previous survival does not establish that every brick is suitable for an exposed external wall.

How to establish a small brickworks

The first task is to investigate demand. Local builders, property owners and conservation specialists could identify the sizes, quantities and types of brick they need. This would help determine whether a works could support itself.

A local enterprise needs enough regular orders to cover wages, fuel, maintenance and the occasional unsuccessful batch.

The second task is to investigate the clay. A deposit which looks suitable may crack during drying or distort during firing. Samples should be examined by a ceramics laboratory and used to make trial bricks. Tests establish how the material behaves and whether blending is necessary.

Trial batches should, where possible, be fired in an existing suitable kiln. This allows the clay and proposed product to be assessed before money is committed to a permanent works.

Choosing and arranging the site

A suitable site would bring together clay supply, water, fuel storage, access and enough space to keep production moving.

A proposed small works would need:

• A clay storage and preparation area.
• A covered moulding workshop.
• Drying sheds or a controlled drying chamber.
• A kiln area with safe access.
• Covered fuel storage.
• Space for cooling, inspection and finished stock.
• Access for deliveries and collection.

The layout should minimise repeated handling. Clay would move through preparation, moulding, drying and firing, followed by inspection and storage.

Before acquiring or developing a site, the organisers should establish the planning and environmental requirements with the relevant authorities. Clay extraction and brick manufacture raise separate questions. The requirements depend on the location, scale and process, including kiln emissions. The UK nations have different regulatory arrangements.

Making the bricks

Clay preparation involves breaking down and mixing the material to obtain a consistent body. A small works might use a clay mixer or pugmill, with hand moulding for suitable products.

Moulds must allow for the shrinkage established through trials. Newly moulded bricks then need controlled drying before firing. Drying too quickly or unevenly can damage them.

The kiln heats the dried bricks according to a firing programme suited to their clay. Cooling also needs control. The finished bricks are inspected and sorted. This sequence requires practical experience as well as equipment.

Handmaking can provide skilled employment. Sensible machinery can reduce exhausting preparation and handling work. A localist enterprise should choose equipment which it can maintain and afford.

Building the kiln

The kiln is likely to be the most demanding part of the project.

For modest, intermittent production, a batch kiln would be worth investigating with an experienced kiln designer. Its capacity should match both demand and the drying facilities.

Construction requires suitable refractory materials, insulation, foundations, combustion equipment, flues and temperature monitoring. The detailed design must follow from the chosen clay, fuel and production rate. A general sketch is insufficient for building a reliable commercial kiln.

An oversized kiln could leave the business waiting for enough orders to fill it. An undersized one could consume too much labour and fuel for the output obtained.

Fuel and the wood economy

Wood firing deserves investigation where a dependable woodland supply exists. H.G. Matthews shows that it can be used commercially. Its wood-fired kilns hold about 60,000 bricks and are stoked day and night for up to five days. This illustrates the commitment involved.

A proposed works would need a fuel budget based on trial firings. Available woodland growth would have to be considered alongside competing needs for household heat and other uses.

Wood fuel also needs preparation, drying and storage. Local availability does not make its cost or environmental effects disappear.

Recovering kiln heat for drying could improve the process where the design permits it. The appropriate arrangement would need specialist assessment.

Quality and viability

Bricks intended for buildings need evidence of performance. Relevant tests include strength, water absorption and resistance to freezing and thawing. Their suitability depends on the intended application and exposure.

The works would also need records linking each batch to its clay mixture, drying conditions and firing programme. These would help identify faults and maintain consistency.

Before full production, the organisers should calculate the cost per saleable brick. The calculation must include rejected bricks, labour, fuel, testing, equipment upkeep and delivery.

The most credible route is gradual: establish demand, test the clay, obtain trial firings, confirm the site requirements and only then commission the permanent facilities.

A local brickworks could become an enduring part of a locality’s essential economy. Its value would come from reliable materials, skilled work and the ability to maintain buildings close to home.