How to Make Modern Adobe Brick

Adobe bricks are made of dirt, straw and water and baked in the sun.

Making adobe bricks is as much art as it is science. A certain amount of know-how is necessary to be able to tell at a glance whether the soil has the right clay-to-sand ratio or whether you should add straw or dried manure to strengthen the brick. Still, with trial and error, even a beginner can make a few of these sun-baked bricks; all you really need is water, dirt and sunlight.

Things You'll Need

• Shovel
• Hoe
• Dirt (at least 12 gallons)
• Water
• Chopped straw
• Wheelbarrow, pit or other area for mixing adobe
• Brick form
• 2-by-4 board

Instructions

1. Mix the dirt and straw together in the wheelbarrow. Add enough water to form a stiff paste and mix it all thoroughly with the hoe.

2. Dampen the brick form with water and lay it on the flat area. Shovel the adobe mixture into the brick form. Pull the long edge of the two-by-four along the brick form so that the board straddles the sides of the form and levels the adobe in the molds. Let sit for three hours.

3. Raise the brick form gently so that the bricks remain on the ground. Let the bricks dry for three days or until their edges begin to whiten. Stand the bricks up on their edges to finish drying, a process that will take three or four weeks.

Tips & Warnings

• If you do not have a wooden brick form, cut a sturdy cardboard box to the exact size you want the finished bricks. Dampen it with a wet rag before filling it with mud, level it and turn it upside-down on the ground; remove the box.

• Traditional adobe bricks are 14 inches long by 10 inches wide by 4 inches thick. They weigh about 30 lbs. when dry. You can make your bricks any size you like.

• Make a few test bricks before you make enough for a building project so that you can adjust the ratio of dirt to water to straw. A finished adobe brick should be able to be dropped from a 4-foot height without breaking.

• A soil containing both clay and sand is best for making adobe bricks. Mix up some soil and water and squeeze the mud; if it sticks together but can be pulled apart fairly easily, try a test brick or two.

• If the adobe cracks while drying, it needs more straw. If it crumbles when dropped, it needs more soil.

• Make adobe when you are sure the process won't be interrupted by rain or snowfall. Moisture will keep the bricks from curing.

• Clean off the brick form immediately after removing it from the bricks, or use a putty knife to chip out adobe remnants before reuse. Leftover adobe in the mold will deform your new bricks.

References

• New Mexico Culture Net: Building Community---the Roots of Adobe
• Desertphile: Making Adobe Bricks
• New Mexico State University: ABCs of Making Adobe Bricks