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The Advantages of Ferrocement for Construction of Schools

The advantages of ferrocement for construction of schools in small or rural communities are real and numerous. Some of the advantages are economic and others are about safety. Although these advantages are also available to larger cities, the small community will more easily direct local skills to this construction project.

The two most important reason to choose ferrocement as the construction material for a school are:

1) The structure will protect the children from harm of natural disasters, earthquakes and hurricanes, for example.

2) The opportunity for a community to express artistic heritage in construction is equal to the sculptural artist's power of communication. A ferrocement school will help teach children that their dreams for a better world are possible. The children will spend their days surrounded by the structural beauty which has come from the imagination of their community. Their minds will grow because they can see with their eyes how much they are loved. Although this concept is possible with any well built and designed structures, the unique designs possible with ferrocement cannot be attained with other materials.

Ferrocement is strong! Think about a basket. A ferrocement structure is like an upside down basket. Imagine a very large basket, one that is large enough to have doors and windows. Now think of this basket full of the children you love; children for whom you have built a school made out of a giant basket. Consider what would happen if an earthquake occurs while the children are in school. When the earthquake is over, the basket will still be there. The children will still be alive and well.

You may experiment with this concept quite easily. Find an old basket and plaster it with cement and sand. Make the thickness just enough to completely hide the basket weave. (Use a mixture of one cement and 2.8-3.0 sand.) Do this inside and out. Be sure to keep the plaster very thin. Let the cement become hard for a week or two (four weeks is considered optimum). Don't let it become dry. Keep it damp so that the cement has a chance to become very hard. After the cement is very hard, let it dry. Be sure to let it dry.

Now test it to see just how strong the basket has become. It would be wise to include as many witnesses as possible for the test. Invite people from nearby communities to see the test. Discuss how strong this basket would be if the armature was steel instead of basket material. Now you understand what ferrocement is. Your community knows more about ferrocement than most people do.

Another way to comprehend the strengths being explained in this article is to notice that a good basket is strong enough to pull an automobile, gently. If you take the fiber out of the basket material you can make a rope. If you take the wire out of ferrocement, you can make steel cable. Chain can be made from the reinforcing steel bars. Also remember this: ferrocement is not ferrocement unless the cement is hardened to optimum.

Note: If there is danger of mud slides during a disaster, be sure to limit, or exclude, windows and doors on the uphill side. Include curved uphill walls and a good foundation to keep the school steady during a potential impact. Ferrocement.com does not recommend prefabricated and bolted ferrocement panels for schools in earthquake zones. There are simply too many young lives in one place at the same time. A huge earthquake may cause cement failure where the bolts are positioned. Contact ferrocement.com to discuss other methods of using prefabricated panels if this method is your choice.

One important idea to keep in mind about ferrocement for a school. The heat of the sun will not be blocked by ferrocement. If the sun shines on the roof all day, it will become hot inside. This will not be a good learning environment. Anything that will shade the cement from the sun will change the inside of the school into a proper area for learning and instruction. Another important idea: rainwater is very difficult to keep from leaking through small, almost invisible cracks in the roof. Water in a ferrocement tank will eventually plug up small cracks. Rainwater is so clean that it continuously rinses the cracks. Rainwater eventually comes through. Should you decide to build a school made of ferrocement, please write to this web site for a discussion of ways to overcome these problems using materials readily available to you.

Consider a second layer of very thin ferrocement on top of whatever you use for isolation from rain, heat, and cold. This will protect the isolation material. See the work of Garrett Connelly (various structures) for plastic over bagged organic material, and then covered with earth: this solves both water and temperature isolation at a reasonable cost (Notice the turned up roof edges which contain these materials, and, at the same time, adds geometric strength).

One last concept is important to keep in mind. Ferrocement gains much strength from curves and bends. Additionally, curves in two directions are stronger than in only one direction. Specifically: a dome, or spherical shape, is stronger than a cylinder. An arced cylinder is stronger than a straight one. A cone is also very strong. All these shapes are sufficiently strong for a school roof. Bent flat planes are also strong. However, they lack the simple engineering which results from a curve which is pleasing to the eye. If a curve looks nice, it will be strong.

The dome presents an acoustic problem for school design because sound is focused and creates a severe echo. Acoustics is necessary to consider, especially with the voices many children.

The economic advantages of school construction using ferrocement are many. Ferrocement will not require maintenance for many centuries, for example. Also, there is no need for fire insurance or costly fire sprinkler plumbing systems. A ferrocement school built with volunteer labor is perhaps the least expensive of all possible building material choices.

Adobe with a ferrocement roof may be even less expensive, at first: this choice is not as good in earthquake zones. Adobe or baled hay, covered by ferrocement, are both interesting possibilities. Old adobe or brick can be repaired quite well if they are covered on both sides with ferrocement. The same thing can be done to old, rotting wood or mud buildings. Note: Bamboo, isolated from the ground by concrete, has been used instead of steel reinforcing bars. Although this website recommends using steel if economically possible, the section about organic fibers is good to read.

Another economic advantage of using ferrocement for school construction is the development of a skilled labor force. Many things will be made from ferrocement once people know how to use it. Water tanks for clean domestic water supplies are a good example of this. Ferrocement aqueducts are a good way to conserve water during transport for agriculture. Development of local political organization associated with water delivery is an excellent example of the secondary political and economic benefits which may be quickly realized when a region chooses to develop a local ferrocement industry.

When the schools, aqueducts, water pipes, and bridges are finished; then the skills are in place to make: tables, benches, large pots, kitchen sinks, houses, strips for tires (instead of full width roads), et-cetera. Ferrocement is a permanent material which is limited only by imagination. Artists are born from a skilled labor force, they will use ferrocement to make the finest sculptural art.

This web site utilizes several languages and maintains a balanced international perspective. It corresponds about labor force training and design assistance as-well-as technical details of construction.