Table of Contents
What is the procedure for mixing cob?
You will need a large tarp and 4 or 5 five gallon buckets. Gather The Materials. Get all of your materials close to your building site. Place The Tarp. Lay out your tarp on a flat space. Measure Materials Onto The Tarp. Dry Mix The Materials. Add Some Water. Mix With Your Feet. Flip And Repeat. Add The Straw, Mix, And Complete.
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.
How long will a cob house last?
How long does cob last? The oldest cob house currently standing is 10,00 years old. If this doesn’t speak to how strong and durable cob houses are, then nothing will. Cob houses are built to stand forever as long as their roofs are maintained, and they are properly looked after.
How thick should cob walls be?
The walls of a cob house are generally about 24 inches (61 cm) thick, and windows were correspondingly deep-set, giving the homes a characteristic internal appearance. The thick walls provided excellent thermal mass which was easy to keep warm in winter and cool in summer.
How do you mix cob with tractor?
How to Mix Cob with the Tractor Determine your cob mixing ratio. Use the tractor and scoop up a bucket full of soil and place it on the middle of your mixing pad. Once you have all of your materials piled up in the middle of your mixing pad you will need to dry-mix them together.
How long does it take for cob to dry?
Cob Houses Are Healthy Once you make your cob, it will need to dry out full and that can take months to years. The bulk of the moisture will dry out of the walls in the first year, but will not fully cure for 1-2 years past that.
What is cob clay?
Cob is an earthen building material that is made of clay, sand, straw, and water. The word ‘cob’ comes from an old English word meaning ‘lump’ or ‘loaf’. The wet cob mixture is used to build thick earth walls; the building technique is very similar to sculpting with modelling clay.
How do you make cob of clay?
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.
How much clay is needed for a cob oven?
So total clay needed is about 25 gallons for a 22-1/2″ oven, about 35 gallons for a 27″ oven, and about 50 gallons for a 36″ oven. Sand: Sand is your aggregate. It reduces shrinkage of the clay as it dries and it adds total strength to your oven walls.
Can you waterproof cob?
Cob is a structural mixture of clay, sand, and straw, used to build walls. The same ingredients can be used to make an earthen plaster. Lime plasters are waterproof in the sense that they do not get soft when soaked, but they are also very breathable.
Can cob houses get wet?
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.
Can cob houses withstand tornadoes?
Cob structures could be made resistant to tornados with appropriate engineering (especially for the roof), but cob does not provide much insulation from the heat and cold.
Are cob houses expensive to build?
A decent cob house can be built for anything ranging around $4,000 – $10,000. However the cost can vary depending on the climatic condition, location and the size of the house. The basic cost, however, may lie somewhere around $2000 – $5000.
What is the foundation of a cob house?
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.
How tall can you build with cob?
A: There is no inherent size limitation on cob or any other building system that I know of. If you look in the literature you will find cob mansions in England and cob towers in South Yemen nine stories high! That being said, cob walls can take a lot of work to build, as do most other natural building techniques.
How do you fix a cracked cob in the oven?
Filling Oven Cracks Use a sponge to fully saturate the oven crack with water. Take a stick or a nail and rough up the existing surface a bit. Stuff your cob mix into the crack and patch. Compress mixture into the crack with your hand or a trowel.
What happens when a cob house gets wet?
There’s all kinds of issues with that but when we look at cob and earth materials what’s special about them is they are vapor permeable so water can get into them, but then it naturally releases from the walls so even if your walls get wet they’re going to have a chance to naturally air out and dry out and there’s no.
Can pine needles be used in cob?
Cob is a type of earth building technique that uses a mixture of earth and a fibrous organic material (typically straw, but in this case pine needles) that adds tensile strength. The mixture of earth, water and pine needles used for adobe bricks is similar to the one used for cob, but the end result is very different.
