From Wet Earth to Adobe Walls

Some buildings are made with adobe bricks. These blocks are made from earth and dried in the air. Wet earth is too soft for a wall. To make useful bricks, builders must shape it and let it dry.

Making the Bricks

First, workers mix soil that contains clay and sand with water. Clay helps hold the mixture together. They may add straw, too. The short, dry plant stems can help keep large cracks from forming as the bricks dry.

Next, workers press the wet mixture into a mold. This frame gives each brick its shape. They lift the frame away and leave the bricks to dry. As water leaves the mixture, it becomes firm. Workers may turn the bricks so different sides can dry.

Building with Dry Bricks

The bricks need to dry before workers stack them. Soft, wet bricks could lose their shape under other bricks. Once the bricks are hard and dry, workers lay them in rows. Mud between the bricks helps hold them together.

Even a dry adobe wall needs protection from rain. Too much water can soften the bricks again. A raised base helps keep the wall above wet ground. A roof that reaches past the wall helps keep rain off its sides.

A drawing of the finished building has the caption, "A wide roof helps protect adobe walls." The roof helps the carefully dried bricks stay dry.