Cob Shed
Sustainable Shed. Cost competitive and far superior to pre-fab big-box store options.
Project Details:
Cob & Cordwood shed. “Cob-wood” combines two natural building techniques: Cob and Cordwood. Cob is a mixture of clay, straw, and sand that hardens like brick, while Cordwood construction involves stacking short pieces of wood to form a wall, with mortar filling the gaps. “Cob-wood” uses cob as mortar between the cordwood logs, creating a natural wall with a distinct appearance. This structure, serving as a garden and tool shed, features a living roof with moss, grass, and flowers. Essential beams anchor the roof to the walls, ensuring stability. Bamboo rafters attach to the beams, creating a sturdy framework for additional roofing materials. This project exemplifies natural building and sustainable design, with only one item purchased from a store. Although labor costs were higher, material costs were lower than conventional methods, resulting in similar total costs but a far superior outcome.
Materials:
Rough-sawn lumber, straw, clay, sand, plants, cordwood, and recycled materials, all sourced locally.
Year:
2013
Introduction to Cob Building
Cob building is an age-old natural building technique that has stood the test of time. It involves using a unique mixture of clay, sand, and straw to create structures that are not only durable but also sustainable. This cob mix hardens like a brick, making it an ideal choice for constructing walls, sheds, and even houses.
One of the most appealing aspects of cob building is its emphasis on using local materials. By sourcing clay, sand, and straw from nearby locations, builders can minimize transportation costs and reduce pollution, making cob building an environmentally friendly option. This method of construction can be traced back to ancient times, with cob dwellings found in various parts of the world, showcasing its long-standing reliability.
In recent years, cob building has gained popularity due to its sustainability, durability, and aesthetic appeal. The process involves mixing the cob ingredients with water to achieve a workable consistency, which is then applied to the structure. This hands-on approach not only creates a strong and resilient building but also allows for creative expression in the design and finish of the walls.
Project Process
Planning and Design
Before embarking on a cob building project, careful planning and design are crucial. It’s essential to consider the building codes and regulations in your area to ensure your project complies with local requirements. This step is vital for avoiding any legal issues down the line.
The design of your cob building should harmonize with the natural surroundings, taking into account the climate and the intended use of the structure, whether it’s a tool shed, garden shed, or house. A well-thought-out design will ensure that your cob building is both functional and aesthetically pleasing.
A stable and level foundation is the cornerstone of any successful cob building project. Planning the foundation carefully will provide a solid base for the walls, ensuring the structure’s longevity. Additionally, the design should account for the elements, with walls built to withstand rain, wind, and extreme temperatures.
Energy efficiency and comfort are also key considerations. Thoughtful placement of windows and doors, along with proper insulation, will enhance the building’s performance. Utilizing materials available on-site, such as clay, sand, and straw, will not only reduce costs but also minimize waste, making your project more sustainable.
Building the Foundation and Walls
The foundation of your cob building is where it all begins. Start by laying it on a level surface, using a mixture of clay, sand, and gravel to create a stable base. This foundation will support the weight of the walls and ensure the structure remains level and secure.
Constructing the walls involves a combination of cob mix and wooden posts. Apply the cob mix in layers, ensuring a solid and durable wall. Aim for a wall height of at least 6 feet and a thickness of at least 12 inches to provide stability and insulation.
During construction, protect the walls from the elements using a tarp or plastic sheeting. This precaution will help keep the cob mix from getting too wet or drying out too quickly. Allow each layer to dry for a minimum of 24 hours before applying the next one.
Once the walls are built, finish them with a smooth plaster made from a mixture of clay, sand, and water. This final layer will create a durable and water-resistant surface, protecting the walls from the elements and giving them a polished look.
Constructing with Cob Wood
Cob wood is a fascinating blend of cob mix and wood, creating a building material that is both durable and sustainable. This combination can be used to construct walls, roofs, and floors, with the cob mix applied in layers to form a solid and resilient surface.
One of the significant advantages of using cob wood is its sustainability. By reducing the amount of wood required for the project, cob wood offers a more eco-friendly option. Constructing with cob wood involves using wooden posts and applying the cob mix in layers, resulting in a sturdy and long-lasting structure.
Cob wood is versatile and can be used to create a variety of structures, including sheds, houses, and garden walls. Its unique and natural look, with the cob mix providing a textured and rustic finish, adds to the aesthetic appeal of the building.
Adding a Living Roof
A living roof is a standout feature of cob building, offering a natural and sustainable roofing option. Constructing a living roof involves layering clay, sand, and soil, topped with a variety of plants and grasses. This green layer not only insulates the building but also creates a beautiful and eco-friendly environment.
The living roof helps to reduce energy costs by providing natural insulation. Additionally, it plays a crucial role in managing stormwater runoff, as the plants and soil absorb and filter the water. Regular maintenance, including watering and pruning, is essential to ensure the health and longevity of the plants.
A living roof is not only functional but also adds a unique and attractive element to your cob building. It provides a natural alternative to traditional roofing materials, enhancing the overall sustainability and beauty of the structure.