What is a cob in construction?
Cob, cobb or clom (in Wales) is a natural building material made from subsoil, water, fibrous organic material (typically straw), and sometimes lime. The contents of subsoil naturally vary, and if it does not contain the right mixture it can be modified with sand or clay.
What is cob on wood construction?
What is Cob House Construction? Cob house construction is an ancient building technique mixing lumps of earth with sand, straw, and water. You can utilize these structures for homes, chicken coops, barns, and more. Cob building is easy to learn, requires no special equipment, and uses sustainable materials.
Is cob a good building material?
If you love the idea of living somewhere that is natural and organic, then this is the home for you. Cob is an extremely durable base material, and the whole structure acts as one monolithic piece. Thus, even during earthquakes, it doesn’t develop cracks. Cob houses are among the best for sound insulation.
How do you build a cob?
Cob is a mixture of approximately 1 part clay, 4 parts sand and 1 part straw. You can buy bagged clay in powdered form (go to Laguna Clay for local distributors) and masonry sand from your local supply store.
Is cob load bearing?
Cob is easy to learn and inexpensive to build. It dries to a hardness similar to lean concrete and is used like adobe to create self supporting, load bearing walls. Cob has been used for centuries throughout Western Europe, even in rainy and windy climates, as far north as the latitude of Alaska.
What is the difference between cob and adobe?
The most basic difference is that adobe is formed into rectangular bricks which are dried in the sun before being used, while cob is built wet. Cob therefore lends itself to organic shapes: curved walls, arches and vaults. Building with cob is a sensory and aesthetic experience like sculpting with clay.
What kind of clay is used for cob?
A: Almost any sort of clay can be used for making cob. Non-expansive clays are best, including those generally sold as “fire clay” and “mortar clay.” Lincoln clays are ideal – very sticky but not highly expansive.
What are the benefits of cob?
Benefits of building with cob:
- Sustainable – the most sustainable form of building there is – cob has almost zero embodied energy.
- Affordable – as long as you have land to build on, anyone can afford to build cob walls.
- Breathable – its a healthy place to live, as there is no damp in a cob house.
What are the benefits of a cob house?
Let’s have a look at some of the highlighting advantages of building a cob house.
- # Low cost of building.
- # Healthy indoors.
- # Energy efficient.
- # Building flexibility.
- # Durable and earthquake resistant.
- # Weather-proof.
- # Termite and fireproof.
- # Sound insulation.
Is cob water resistant?
Why doesn’t it wash away in the rain? Cob is very resistant to weathering. Because of its porous nature, it withstands long periods of rain without weakening. However, too much exposure is best avoided by the “boots and cap” strategy: wide roof eaves to protect the walls and an impervious foundation.
How thin can cob walls be?
The thinner that cob walls are the less load bearing capacity and thermal mass that they will have. I recommend the width of cob walls be between 18 to 24 inches as a standard. This gives plenty of load bearing capacity for a one story building and plenty of thermal mass.
Is cob as strong as concrete?
Cob has unique properties which make it as strong and more durable than concrete (see ‘How is Cob so strong’) the oldest Cob building is over 10,000 years old. Cob is resistant to fire, termites and mould.
What is a “cob wall”?
This is a technique for building walls in which wooden strips are woven together into a lattice. Then it is “daubed” with a sticky soil material that usually consists of earth, sand, dung, and straw. Like what you just read? Join our mailing list to receive a free download of Build a Cob House: A Step-By-Step Guide to get you started.
What is a cob house made of?
Cob is a mixture of clay, sand, straw, and water. To build a cob house you will essentially need three main components: foundation, walls, and a roof. Here are some of the different styles and systems for building a cob or a hybrid cob home.
What is the difference between Adobe and cob walls?
Wall Systems. Adobe. Adobe is very similar to cob except that adobe is shaped into bricks (with forms) and dried in the sun. Then the dried bricks are stacked and mortared together. Bale Cob. If you live in a region that gets very cold in the winters, you might want to build a hybrid bale cob wall system.
What is a hybrid Bale cob wall system?
Then the dried bricks are stacked and mortared together. If you live in a region that gets very cold in the winters, you might want to build a hybrid bale cob wall system. A bale cob wall consists of stacked strawbales covered with cob on the sides and mortared together.