Sustainable Dwelling Regeneration
jump to: systems and materials| applications | bio-climatic design | refrences

*UNDER CONSTRUCTION!!*
Introduction

Once again, Nature has flexed her muscles and hundreds of thousands are displaces and homeless. These people are now facing the huge tasks of dealing with their loss and rebuilding their lives from the sand up.

The process of rebuilding that has started is a very sensitive and complex one. Millions of dollars of aid are coming in and several relief organizations are stepping up to help the rebuild process.

This project is designed to maximize the amount of aid given by exploring sustainable, alternative building technologies, while looking at traditional Indonesian building methods and customs.

Rebuilding sustainably will help protect the already stressed environment and possibly create a more comfortable living environment. Completely modern prototypes will be presented while some prototypes modifying traditional housing types with alternative methods and materials will be explored. Also, several technologies are presented in a manor in which they can be applied to several building types and sites. For example, if a village still wanted to build in the traditional style, some of these new technologies could be applied to that building or if a set of modular housing units were built by a relief organization the technologies could also apply to these buildings.

The first section of this project reports alternative building material and systems that are applicable to Indonesia, where as the second part explores the application of these technologies and materials at different scales and sites.

 


 

Systems and Materials  
jump to: modular contained earth (earthbag) |earth-rammed tires |bamboo |

Modular Contain Earth (Earthbag)



Earthbag is a method of construction using plastic or textile casings (earthbags) packed with soil, and sometimes sand, gravel and cementitious materials. It has grown in popularity as a natural alternative building method primarily in the United Sates. It can be used to construct foundations, walls, and domed structures. Earthbag is one of the most inexpensive building methods, and is very valuable to areas that are prone to flooding, hurricanes, wildfires or areas with no wood or clay. Earthbag construction technique requires few skills, and if faster than other earth building methods. Few tools other than a shovel is necessary those can usually can be hand made.
Architect Nader Khalili at Cal Earth in Hesperia has explored the use of earthbag construction both as residential houses and emergency shelters. Through his work and the work of students at the California Institute of Earth Art and Architecture, this technology is proven to be a viable solution for rebuilding communities after a war or major disaster.
Earthbag construction is a very promising option for the rebuild in the Aceh area. For both temporary and permanent solutions. Emergency shelters made from sandbags and barbwire can be constructed in a few hours and have been proven to last for three winters. As a permanent solution, earthbag dome structure could be built that would be covered in cement or lime plaster. In the Aceh region, all of the other materials except for the bags can be found locally.

examples  

emergency shelter

domed home vaulted interior vaulted home
*Eathbag images coutesy of calearth.org
construction materials

 

bags

Two types of bags are available: Hessian (burlap) or polypropylene. The polypropylene bags are the only sutable for the area of Indonesia because of the high levels of sand in the soil. The weaker the fill material, the stonger the bag must be. If only dry sand is used as a fill, the bag must be made of a non-degradable material that is strong enough to with stand dead and live loads.

polypropylene
Polypropylene bags are made of woven plastic. Polypropylene bags will deteriorate if exposed to (UV) rays. Steps should be made to protect the bags from sunlight both before and after construction. UV resistant bags are also available, however more expensive.
In the United States, manufacturers sell the polypropylene bags for around 22 cents per year plus delivery. The sacks are available in a variety of widths.

reused bags
Recycled seed or feed sacks made of polypropylene can be obtained from factories or stores that bag these products. The bags can be sewn together to increase the length.
fill
A typical adobe mix of sand and clay soil is ideal for earthbag construction. A mixture of sand and lime or lime-rich coral sand that would be common in these regions is also sufficient.
All organic matter, rocks, and sticks should be sifted out of the soil. Any material that degrades that is left in the bags could create pockets, weakening the structure. Also remove all topsoil and only use the substrate and fill material. After the fill material is sifted and lime or coral sand is add the bags can be filled. The fill can be used either wet or dry however when using lime the fill should be moist so that the material sets for structural support. The perfect moisture content is tested by grabing a hand full of the fill and sqeezing it. It should hold its shape but not feel wet.
other materials
4-point barbed wire is laid between courses to keep the bags from slipping. As a rule of thumb, if the bag is less than 12 inches wide, only one row is needed. Two or more rows of barbed wire may be required for rows wider than 16 inches.
tools
The most important tool in earthbag construction is a shovel. Shovels are used to excavate the fill material, and fill the bags. Wheelbarrows are needed to transport the fill material and can be used to mix up the cement or lime into the soil mix. Coffee cans are useful to fill the bags. Cans or sturdy cardboard tubes are good for keeping the ends of the bags open as they are filled.
Soil tampers are needed to compact the bags. Filling a plastic container with concrete and inserting a stick into it can make a tamper. The tamper should cure for two weeks before use. Heavy flat stones or bricks can be used.
A hoe is helpful when mixing stabilizers like cement. A blade/scissors for cutting the bags, a level, tape measure, barbwire cutters, gloves, a trowel, and water hose and water bucks for carrying water are also needed.
Forms for vaults, domes and arches are needed if creating any of these shapes. The forms can be made from metal or plywood. Bamboo plywood would also work well and these forms can be used over and over again.

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Earth-Rammed Tires

There are probably hundreds if not hundreds of thousands of tires that are amongst the debris from the tsunami. These tires which would normally be considered garbage could be used to create new homes. The U module is the most commonly and efficient shape for earth-rammed tire construction. U modules should not be created larger than 18 feet wide and 26 feet deep. Structures larger than this should be made form several modules or another design. Other designs using many different shapes have also been built to best adapt to the climate. Also earth-rammed tire walls should not exceed 10 feet because of their massiveness.

examples

U-module home

Earthship home interior cylinder home
Source:http://www.students.ncl.ac.uk/n.m.simpson/earthships.htmSource:http://www.students.ncl.ac.uk/n.m.simpson/earthships.htmSource:http://angelsnestretreat.com/gallery/view_album.php?set_albumName=Sustainable-Ecolonomic-Prototype-Home
construction materials

 

tires

The automobile tires can be used as found. No modification to the tires is necessary.

fill

The fill for the rammed earth should consist of a mix of sand, clay and 10 percent portland cement. The fill should be moist so that the cement can set up. The moisture content is tested by grabing a hand full of the fill and sqeezing it. It should hold its shape but not feel wet.
tools
Wheelbarrows for hauling the fill, sledge hammers for compacting the earth inside the tires, and a level are all needed materials. Other helpful materials are; tampers as shown above, hoes for mixing fill, and used cans to fill the gaps in the tire walls.

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Bamboo

Bamboo has rapidly become a popular building material, proving to be a much more sustainable alternative to wood, it is valued for its strength and lightness. In comparison to the rigidity of steel or concrete, bamboo's high flexibility is well suited for earthquake prone areas. In Indonesia, it has proved to sustain storm and earthquake damage, however, its strength can be compromised with contact with wet soil and termites. It is a relatively strong material with a hard, clean surface, and can be easily cut with simple tools. Bamboo growth is fairly rapid, and is found throughout this region, making it an inexpensive alternative to timber, and can also be grown as a crop plant. Although bamboo is abundant in Sumatra, it is less so in the Aceh Province.

examples

wall treatments

rafters furniture floors beams

construction materials

 

bamboo

Many different species of bamboo are available. From grass like species used for woven materials to bamboo poles that are 10 inches in diameter.

tools
Tools for bamboo construction is much the same as traditional wood construction. Drills for drillings holes for joints and saws for cutting the bamboo are the most necessary. Manual and power tools both work well however power tools have become much more efficient.
strength comparison

Material Stress Mass per Volume Ratio
Concrete 8 N/mm2 2400 0.003
Steel 160 N/mm2 7800 0.020
Wood 7.5 N/mm2 600 0.013
Bamboo 10 N/mm2 600 0.017
Source: Elizabeth & Adams. Alternative Construction:Contemporary Natural Building Methods

 

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Applications

jump to: equatorial house design | prototypes |

Basic Essentials of the Equatorial House
site choice
  • Orient house toward the prevailing wind and not the sun The wind will help cool the house by cross-ventilation.
  • Shaded valley are generally much cooler and protected.
  • Locating house under a grove of palms or overshaded by trees can induce ventilation. The trees should be permeable to wind the house level, prune the trees up if needed.
  • Build on the highest ground if possible to help protect residence from tsunamis.
  • Build on stable soil that will resist mudflow in heavy rain and liquefaction caused by earthquakes.
house design
  • Walls should be white or reflective, and shaded by wide eaves and palms or other trees.
  • Wall materials should be light and permeable to wind if possible. Natural woven fibers or mosquito screens.
  • Heat systems like cook stoves or hot water heaters should be detached from the main house as outdoor kitchens.
  • Vertical louvres and window shutters should be used to allow for cross-ventilation.


Prototypes

earthbag variations

eco-dome

 
  • Built from local earth-filled Superadobe coils (soil-cement or lime-stabilized earth).
    Tree free.
  • Maximum use of space through alternative options.
    The main dome and four niches, depending on local code approval, can function as:
    a) main living room, entrance hall, kitchen, bathroom, bedroom (called "bed-womb" because of it's small, organic form!)
    b) living room, entrance hall, and three bed-rooms.
    c) living room, entrance hall, two bedrooms, and a bathroom.
  • Self-contained single unit
  • Can be repeated and joined together to form larger homes and courtyard houses.
  • Can be built by a team of 3-5 persons.
  • Designed with the sun, shade and wind in mind for passive cooling and heating.
  • Wind-scoop can be combined with a rated furnace unit, depending on local code approval.
  • Interior furniture can be built-in with same material.

earthbag foundation home

  • Earthbag creates strong foundation that allows floodwaters to pass through. Also foundation would move like a boat during an earthquake and resist structural failure.
  • Above living quarters could be created in a traditional manner.
  • Bamboo and other materials could create the living quarters.
  • Upper story could be modular and could be easily disassembled and reassembled.
  • People could reuse the earthbag foundation like they traditionally used wooded stilts of traditional homes.

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Bio-climatic design  
cross-ventilation for houses

Vented ceiling slopes allow hot room air to escape, and cool trellis air to enter. (Figure Source: Permaculter A Designer's Manual by Bill Mollison.)

The key to successful cross-ventilation are that the air that is flowing need to be able to follow a simple path (no corners), and that large vents are used that allow for a lot of air to pass through.

cool air from shadehouse and buried pipe.

A 0.5 x 0.5 m tunnel 1 m deep and 20 m long sloping to the outside intake to de-humidify and cool the air, with a solar chimney to draw air through the house. (Figure Source: Permaculter A Designer's Manual by Bill Mollison.)

Metal chimneys or a hot roof (a roof that is unventilated) are the best cooling systems in a tropical house. The metal chimneys or hot roof draws in cool air from underground pipes. Being underground the earth cools the air that is in the pipes. The air that is drawn in from the pipes is more dense so it naturally sinks to the lowest level of the house but a fan can move the cool air throughout the room of the house.

The cool air pipe needs to be buried at least 1 meter, and should be 15-20 meters long. The pipe should be laid at an angle that slopes away from the dwelling to allow for the condensation that develops to drain away from the house. The Outlets of the pipe should be covered with screen to keep animals out.

A shade house which is a trellis covered with vegetation can also be a good for creating cool air that could be utilized by creating vents in the exterior wall of the structure and at the eaves of the roof.

 
Designing a house with large over-hanging eaves, shades the house and also brings rain water from the roof farther away from the house.

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Refrences

Elizabeth, Lynne, and Cassandra Adams. Alternative Construction: Contemporary Natural Building Methods. (New York: John Wiley & Sons, Inc. 2000).

Mollison, Bill. Permaculture: A Designer’s Manual. Second Edition (Tasmania: Tagari Publications, 1988).

California Institute of Earth Art & Architecture. 25 Feb. 2005.

http://www.calearth.org

 

 

 

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