Adobe

This is Robert Cohen with the VOA Special English Development
Report.

These days, stories about adobe are usually about Adobe, the
California company that makes computer products. But this report is
about adobe the traditional building material made of soil.

Adobe is shaped into bricks that can be placed on top of each
other. They are used as a low cost way of making houses. They can
substitute for other building materials such as wood and steel.

Adobe is soil that contains at least forty percent clay. In its
purest form, clay can be shaped and stretched and used to make
objects. Clay becomes very hard when it is put in a fire or a
special oven.

Adobe becomes a sticky mud when it is mixed with water. Liquid
adobe mixture can be poured into containers called molds. This way
the adobe ca be shaped into bricks of the desired size. Adobe bricks
must be completely dried before they are used. That is necessary so
that the walls of a building will not shrink or break.

Too much water can make adobe weak. Sometimes other materials are
added to the adobe mixture. These materials help keep the water in
correct balance with the soil. This will help the adobe resist
changes in the weather and humidity.

One material that is commonly added to strengthen the adobe is
straw. Straw is the dried stem part of plants such as wheat, millet
and sorghum. Straw is especially popular in places where the clay
content of the soil is high. Other materials such as lime and cement
can be added to strengthen the adobe. About once a year, houses made
from adobe should be given a layer of mud. This "paint" job helps
keep the adobe strong.

Adobe can take a long time to dry and become hard. So the bricks
should be made in hot dry weather. If the weather is right, the
bricks should dry in seven to ten days. People who work with adobe
must experiment. They must find the right combination of soil mix,
water content and drying methods.

Many people around the world have found that adobe is a low cost
way to make a house or farm buildings. You can get more information
about building with adobe from the organization Volunteers in
Technical Assistance, or VITA. VITA is on the Internet at
www.vita.org.

This VOA Special English Development Report was written by Gary
Garriott. This is Robert Cohen.