Rammed Earth Housing By Caity

What does it look like? Rammed earth typically has horizontal stratification marks that can be used aesthetically, or can be eliminated. Color can vary depending on the types of earth used and it is easy to create all types of structural features such as leaning walls or adding stones, shapes, and other objects to the walls. You can cover the walls with paint, wallpaper, stucco, and anything else that pleases you.

Appearance I decided to make my walls out of whatever local materials are available, and then cover the walls with tan colored stucco. My window panes, doors, and other decorative features will have a burnt- sienna color to them.

Appearance I have also chose to use dark stones to emphasize the corner posts on the front of the house, the exterior trim around the door, and the structural posts that will hold up a structural beam over the front door. The roof will have brown colored shingles to blend with the tan of the walls to make the house look bigger.

Structural Capability It is very strong and can be used for multistory, load bearing walls. At 2 feet thick, it performs best. Built with steel reinforcements, it is great for areas prone to cyclones and earth quake zones because the panels are interlocked and move with the tremors.

Thermal Mass Rammed earth is known for it’s thermal mass. It heats up slowly during the day and slowly cools at night, leaving an almost constant temperature and lack of need for an AC or heater. However it needs insulation during the colder seasons because it’s insulation factor is not great.

Roof Insulation In the roof I will use recycled cellulose fiber for insulation. It is sprayed on using compressed air and even though it is more expensive than most roof insulators, in the long run, you will save big from cutting energy costs and it is green. The nice thing is that it is treated with environmentally friendly fire retardant and vermin repellent. The roof will use Thermostat Plywood Radiant Barrier Sheathing that will reflect up to 97% of the sun’s radiant heat as the roof shingles will be dark. It is made by Georgia Pacific, an Energy Star partner.

Wall Insulation I will use natural fiber insulation. It is made out of mostly recycled cotton, which uses far less energy to process than the usual fiberglass insulation. It is also 100% recyclable and is better for your health as it is all natural and feels like your own clothing against your skin. It retains r-value in cold conditions because it is denser than fiberglass, and it also has acoustic properties that control noise.

Power System I will use a solar power system from Home Depot from BP Solar Home systems. It should cost $25,000-$35,000 after rebates. From Home Depot they promise that it is more affordable because federal, state, and local government and utility incentives are now available to cut thousands of dollars off the cost of the power system.

Lighting All lighting will be CFL lighting (compact fluorescent lighting). It uses 75% less energy, emits 75% less heat, and lasts 10 time longer than the regular light bulb. All lights, interior and exterior, will be energy star products.

Kitchen Appliances I will use Kenmore kitchen appliances, an energy star partner. They are constantly top rated by consumer reports for their sustainability, durability, and reliability.

Clothes Washer I will use a front loading clothes washer from energy star. I can save tons of water and can save $550 in operating costs over the product’s lifetime if purchased.

Energy and Power The down side to energy efficient appliances is that they are more expensive. However they lower energy bills, and benefit the environment. In my house there will only be energy star rated appliances for maximum sustainability.

Durability and Moisture Resistance Some buildings made of rammed earth have been around for centuries, such as the Great Wall of China. This shows how durable rammed earth can be. However, since the walls are porous by nature, they need a water repellant. In my house, I will use Stabilized Earth Water Repellent made by Tech-Dry products.

Environmental Impact Rammed Earth is very environmentally friendly. Rammed earth has a high thermal mass, meaning less energy used. The carbon footprint is minimal compared to standard construction due to the use of local materials, which cuts transportation pollution. It is made of mostly natural materials using less wood in construction, which is scarce. They are also naturally fire resistant and bug resistant.

Water System In my house there will be an Energy Star rated water heater There will also be a grey water system that will take water from showers, washers, etc, and filter the water to be recycled into places like the backyard watering system, or into the toilets. There will also be only low water level toilets.

Local Materials Availability and Cost The house will be built in Vacaville, CA All materials can be easily found in Vacaville at any home improvement store or in the land being built upon. Costs will range from $55 per square foot to $85 per square foot realistically.

Construction Process A foundation is laid down of reinforced concrete that corresponds to the local splash and frost lines. First you must mix soil (50-70% sand), 30% clay, 3% portland cement, and 10% moisture. Then, forms must be made for the walls which can be made from wood or tires.

Construction Process After the forms are made, the earth is “rammed” into the forms until hard. Since rammed earth hardens as it dries, the forms may be removed as soon as they are full. Each day the structure gets stronger as it is let to set.

Construction Process After completing the walls, stucco or plaster will be applied to the walls so that they don’t deteriorate. Then structural beams are put on for the roof. Then the insulation and shingles are added.

Construction Process To put in windows and doors, you must make your forms shaped ready to place in the door or window. Therefore they must have the holes cut out already. Electrical wires will be inserted by drilling holes and feeding the wires through them Insulation is usually placed between two layers of the rammed earth like a sandwich.

Floor Plan

Justification Why is my house energy efficient?  South facing windows with 3 foot long eaves Lets in light during winter, less in summer

Justification  Clearstory windows over the garage Heats the garage and heat flows through the hallways in the house near the bedrooms.

Justification  Rammed earth is energy efficient Great thermal mass, which means almost a constant temperature

Justification  Insulation is decomposable Keeps the house warm in the winter, recycling is good

CHOSE RAMMED EARTH! In Jiayuguan, China, built during the Ming Dynasty (1368–1644).