What Is Thickness Of Cob Wall?

18 to 24 inches thick.
Rammed earth walls could be mistaken as cob. But they are much thinner at 9 inches only, while cob could be 18 to 24 inches thick. The other differences being smoother surface of rammed earth, very few surface cracks, no need for plastering and such others.

Is cob structural?

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 strong is cob?

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.

How do you wall a cob?

Using the hands and feet, each piece of cob is smeared, pinched, and stomped together as they are applied to the walls. Stomp or smear together any cracks or gaps between cob pieces so they don’t come apart when dry. In reality, most cob walls never turn out to be completely monolithic.

What is the difference between adobe and cob?

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.

Are cob walls 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.

Does cob absorb water?

Corncob is an enviro-friendly and biodegradable product that can be used to absorb a variety of fluids, including water, oil, grease, sludge, and coolant, making it ideal for routine shop spills or large industrial absorbency needs such as oil fracking.

What are the disadvantages of cob houses?

Disadvantages:

• Labour intensive.
• Relatively slow to build.
• Obtaining a mortgage from lending institutions is difficult.
• Cob walls cannot be laid in wet or freezing weather.
• Insects, notably termites and small rodents can burrow into the walls and weaken them.

Can cob houses withstand rain?

Rain can be one of the main enemies to the integrity of your cob structure. But at the same time, cob walls can actually withstand a tremendous amount of water hitting them and still be fine. Its more the slow “drip” and consistent dampness that we want to avoid.

What is the R value of a cob wall?

R-0.22 per inch
According to the Cob Code Appendix U on Cob Construction, the unit R-value for cob walls is R-0.22 per inch of cob thickness. This comes out to about R-2.64 per foot thick of cob wall.

Does cob need insulation?

They can survive the blazing heat and winter freezes by burrowing and living underground. Put bluntly, cob is a pathetic insulator. This goes for any earthen building material. But what earthen materials lack in insulation properties they make up for with thermal retention.

What is the best foundation for a cob house?

Concrete has been used for thousands of years by builders for good reasons. It is a great material for foundations. It’s monolithic, very strong, widely available, it uses 99% natural ingredients, and it can be poured into almost any shape that you want. Concrete is a great choice for footers and stem walls!

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 material is the cob made of?

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 vary, and if it does not contain the right mixture, it can be modified with sand or clay.

Do you need sand for cob?

There are some rare areas where you will find soil that naturally contains the right amount of aggregate-to-clay ratio to make cob, but this is not usually the case. One of the main guidelines for choosing sand for your cob mixture is to use a rough and coarse sand that has many different particle sizes included in it.

Can you put nails in cob walls?

Nails must be hammered in to the sides to hold it in the wall. You are going to have to keep checking they are level as you build up, as the cob is likely to push them around a bit. The horizontal bar inside the wall also adds strength and stops the deadman falling out.

Can you drill into cob walls?

Cob is purely mud so a normal drill will be more than sufficient. Cob walls hate vibration as it breaks down the bond holding it together weakening it.

Are cob walls soundproof?

Build a cob home for your family and it will last for many many generations to come. Earthen walls have very good sound-absorbing properties that keep it quiet inside, both from exterior noises and noise generated in the same building.

What is the mix for cob?

Cob is a mixture of clay, sand, straw, and water. Clay is the binder; sand gives the mixture strength; straw provides tensile strength (think “rebar”); and water helps activate the clay to hold the mixture together while building.

What are the types of cob?

A cob is traditionally a draft type pony. Should be of a stout build, with strong bones, large joints, and steady disposition; it is a body type of horse rather than a specific breed.

Can you use a cement mixer for cob?

A concrete mixer will only tumble the materials round and round. This works for mixing very wet material such as concrete and some earthen plasters. A concrete mixer will not mix cob.