Alternative design of Cob and Under ground living-part 4

Hi there,

This time we will be talking about cob houses and underground homes, both designs having there own pros and cons. These two styles are definitely worth considering when planning an alternative home, come and read with me and i will explain why.

Cob is a very old traditional method of building buy combining dirt, clay, and straw or other fibers. Cob is normally applied by hand in large gobs (or cobs) which are tossed from one person to another during the building process. The traditional way of mixing the clay/sand/straw is quite unique by using your bare feet; Reason being, it is quite labor intensive. One of the luxuries of living in this day and age is that we can utilize plant and machinery ie. an excavator or a backhoe, to take some of the manual pain out of the equation. Although it considerably diminishes the organic nature of the design and does boost the overall cost of the project.

“you want roughly between 2 parts clay, 1 part sand, a sprinkling of straw and a little water”.

Straw cob can have some insulation it would not make a very comfortable house in a climate of extreme temperatures. The wonderful thing about cob construction is that it can be freeform, and turned into as modest or as sculpturally desired. Cob was a common building material in England in the nineteenth century, it was cheap and plentiful and a lot of those buildings are still standing today.                 (pic-)

You’ll need to do a soil test on your own dirt to see if it’s suitable for cob building, but generally, most sites have some sort of usable soil.

Cob is also very durable if it is properly sheltered from the rain.  A good roof will protect the walls and has the potential to last for hundreds of years. When the house started to weather and begins to look bad, you can actually just re-apply a new layer of cob on to the outside to make it like new again.

Cob is very affordable in most cases, all the materials can be found on your own land or can be obtained in large quantities for quite cheap.

For example the $500 house…


Cob houses are very fire resistant because they are built out of mostly clay and sand, you don’t have much for a bushfire to catch a light.  Cob is a popular choice for areas that prone to wildfires or other extreme weather.

Creating a cob house can create a very healthy air quality for a home. Once you make your cob, it will need to dry out fully 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 after that.

Once you build the house and add a roof, you should allow it to breathe for many months before moving into it so you’re not exposed to the mold and mildew. Then I’d start the internal sealing process. When you do move in, a dehumidifier will be important to draw a large amount of moisture out of the air

There is something so cozy, appealing and comforting about the curves in a cob house.  You can have these organic forms that allow elements just flow into each other.  It is hard to put your finger on exactly what it is about cob houses, but they definitely have this magical quality, unlike no other home I have walked into.

check out the link below for some fantastic advice and tips on building a cob home.

Underground home

Underground construction is not a new concept, it has been around for thousands of years or so.  Mainly developed through mining and more currently in the transport, housing, and commercial industries. Making it easier to go underground with a more of a controlled environment as opposed to building on some of the harshest environments in the world.

Underground housing (earth-sheltered housing or earth ships) refers specifically to homes that have been built underground, sometimes either partially or completely buried underground. This style of home has grown increasingly popular since the ’80s because of there diverse and extremely low impact on the environment and supports the green building movement.

Thousands of people around the world live in underground homes. There is a misinformed belief that underground homes are dirty, damp, dark, claustrophobic and unstable places to live. This is generally due to a lack of information and knowledge about building regulations and specifications, as opposed to traditional building practice they have become used to.

Underground Dwelling Design

The design of an underground home is determined by the conditions and layout of your site, which makes all the homes unique. You must carefully consider the soil type, density and compaction levels, groundwater levels, load-bearing properties, and slope stability. Construction materials need to be waterproof, durable and strong enough to withstand underground pressures that’s why concrete is considered a perfect choice.  Not only can you turn it into any shape or size,  durable, strong and (quality concrete it also gets stronger with age as it never entirely goes off). Commonly used in the roof areas of the dwelling.

Concrete pic

  Underground building methods and styles

  1. Constructed Caves – made by tunneling into the earth. Its a popular method around the world, although an expensive and very dangerous procedure.
  2. Cut and Cover – these are made by assembling precast concrete pipes and containers into the required design of the living space, and then burying them in the ground, basically a culvert home.
  3. Earth Berm – home is built on a flat bit of land or a small hill and then buried, only leaving a wall or roof open for sunlight.
  4. Elevational – the home is built into the side of a hill with the front of the home left open.( similar to 3)
  5. Atrium – Courtyard homes, the rooms are built below the surface and around a sunken garden or courtyard that lets in natural light.
  6. PSP – stands for post, shoring, and polyethylene. House is built by excavating the ground, ramming in posts and placing shoring (boards) between the posts and the earth. Then placing polyethylene plastic sheets (for waterproofing) behind the shoring boards.

All underground homes need well-designed and have ventilation systems to control indoor air quality and humidity. Natural daylight design using light atriums, shafts and wells can be used to improve the quality of underground living.

Advantages of Building Underground

they can be built on steep surfaces and can maximise space in small areas by going below the ground. The materials excavated in construction can be used for the building process (saves digging).

Underground houses have less surface area, This means less building materials which means cheaper overall cost of the build. They are also wind, fire, and earthquake resistant, providing a safe environment in extreme weather conditions.

One of the greatest benefits of underground living is energy efficiency. The earth’s natural subsurface temperature remains surprisingly stable, so underground dwellings benefit from geothermal mass and heat exchange, stay cool in the summer and warm in the winter. This saves on average 80% in energy costs. For a very educating read its a little pricey but totally worth the read its a small cost considering the information you get click on  Sustainable Built Environments

By also incorporating solar designs, this energy bill can be reduced to zero, by using hot water and heat to the home all year round. An additional benefit of the surrounding earth is noise insulation (no noisy neighbors lol). Underground homes are exceptionally quiet and peaceful places to live.

Click below to find out more…

GOWE Grid tie solar power system from 1500W to 10KW(3KW)

My thoughts…

A well-designed underground or cob home can be a stylish, comfortable, secure, bright, unique and inspiring place to live. More than that they can be an excellent example of the ideal eco-home, demonstrating energy efficiency, low-impact design, and harmony with its natural surroundings. With the increasing demand and ever diminishing real estate and not to mention the prices involved in traditional building methods. It seems only natural that people are now looking at building alternative sustainable life-styles. For me, it just seems an obvious way to go for a brighter future.

Thank you for reading

Shawn Fitzgerald





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