Made of Mud

You know by now that dirt is good for lots of things: growing plants, feeding worms, even the occasional mud bath. But building houses? Absolutely.

There are lots of reasons to build with dirt. It's plentiful, really cheap, and fireproof. Thick dirt walls keep you warm in winter and cool in summer. And you can build a whole house with few tools other than your own two hands.

In fact, dirt is so good for building things that half the people in the world live in houses made of mud. Maybe even you!

Mud works best for building where it's dry for most of the year. If there's too much rain, the walls of your mud house could melt like ice cream on a warm day. But in places that don't see many storm clouds, mud bricks, which are baked hard in the sun or in a hot oven, can be as strong and durable as stone. In Africa, some mud-brick buildings have been standing for thousands of years.

In the southwestern United States, American Indians built four-story apartment buildings from mud bricks called adobe. And on the Great Plains, the first white settlers saw an ocean of grass as tall as oxen, but few trees for building houses. So they made their houses out of sod, dirt held together by the thick, tangled roots of prairie grass. Sod was stripped by a plow, then cut into bricks that were stacked to make walls and roofs. Even the floors of “soddies” were made of dirt. Sodhouses were muddy when it rained, but good for growing a rooftop garden.

Most sod houses became worm food years ago, but many of the buildings you see every day are pure dirt. The bricks that may make up the walls of your house or school are made of clay that's been baked in a fiery kiln. So the next time someone says a building is made of bricks, correct them. You know it's really made of plain old dirt.


To make mud bricks, you'll need dirt that's a mixture of sand and clay, straw to help hold it all together, and a few weeks in the sun to let the bricks dry.

Step 1.
Mix the dirt with water and straw. Sure, you could use a shovel, but wouldn't you rather feel the mud squishing between your toes?

Step 2.
Pat your mud into a wooden mold. Be sure to pack it tight to get rid of air bubbles.

Step 3.
Pop out the wet bricks, then let them dry in the sun. The bricks have to harden for two weeks or more.

Step 4.
Stack the dried bricks, using more mud as mortar. Plaster the outside of your finished wall with a thick, smooth mixture of mud and straw.

Step 5.
Voilà! A mud-brick house. If you plaster the walls with fresh mud every year, the house might still be standing when your great-great-grandchildren are reading Ask.

Vocabulary

  • kiln: An oven or furnace used to harden, dry, or burn pottery, bricks, grain, or lumber.

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Activity

  1. Why might it be better to make a building out of mud than wood?
  2. What other kinds of materials in addition to wood and mud do people use to build their homes? Think of two other kinds of materials that people use to build their homes. Where would you find each kind of home? Write down two other kinds of materials people use to build their homes and where you find these kinds of homes.