How to Make Adobe Brick

Adobe brick is one of the oldest and simplest building materials to make. The process dates back to Biblical times when the Israelite slaves formed mud bricks for their Egyptian captors from the loamy soil of the Nile Delta. The recipe hasn't changed through the thousands of years since then. Here's how to make these simple and durable building blocks.

Difficulty: Moderate

Instructions

Things You'll Need:

• Measuring tape
• Saw
• Hammer
• 3 Lengths of 2 by 4 lumber
• Nails
• Shovel
• Hoe
• Five gallon bucket
• Water supply
• Straw (optional)

1. Find a good source of loamy clay soil. Dirt from the side or top of a natural hill are usually good sources because the dirt in these hills has withstood erosion from wind and rain for centuries. Avoid dirt from old stream beds or low lying flood plains because they are usually full of fine silt and rocks and have little or no clay in them.

2. Build a brick mold from 2 by 4 lumber. Use 2 5-foot lengths for the sides of the frame and cut a third 2x4 into 6 14-inch lengths. Nail the 14-inch cross pieces to the two 5-foot lengths spaced 10-inches apart. The finished frame will look like a ladder with 5 10 by 14 inch openings so you can form 5 10-by-14-by-2 inch bricks at a time.

3. Dig a hole in the ground approximately 4 feet long, three feet wide and three feet deep. Fill the hole with water and allow the water to drain out completely. This takes 12 to 24 hours, and you will use the hole to mix the adobe for the bricks. The water will stabilize the hole so the sides won't crumble while you're mixing the adobe mud.

4. Fill the prepared hole about half way with the loamy soil. Add water with the five gallon bucket a little at a time and mix it with the hoe. Use enough water to form a stiff mud. While some traditional adobe recipes call for adding small amounts of straw to the mix, it really isn't essential. You can make strong ,durable bricks with only soil and water.

5. Lay the brick form on the ground and shovel enough adobe mud into each of the form sections. Fill each section completely and use the shovel to tamp the mud into all the corners, making sure there are no air bubbles or voids in the mud. Use the edge of the shovel to level the tops of the bricks even with the top of the form.

6. Allow the bricks to set up a bit before carefully lifting the form off of them. Leave the wet bricks in place and move the form to another flat spot for next set of 5 bricks. Repeat this process of mixing mud, filling the forms and lifting the form off the bricks until you have all the bricks you need. It's a slow process, and it may take several days to make enough adobe bricks for your building project.

7. Sun dry the bricks for several days before moving them. When all the edges turn white, the bricks are dry enough to handle, but they are still not cured enough to use. Turn all the bricks on edge to dry the top and bottom surfaces. The drying process takes up the 3 weeks before the adobe bricks are cured and ready to use.

Tips & Warnings

• It's a good idea to make a few test bricks before tackling a big project. If you can drop a dried brick flat from a height of 4 feet without damaging it, it's strong enough for your building project.
• Each finished 10-by14-by-2-inch brick weighs about 30 pounds when thoroughly dried.
• Use the same adobe mud to mortar the bricks together in your building project.
• Make sure you have good, warm weather for the entire brick making and drying process. Once they are thoroughly dry, rain won't damage them, but wet weather will weaken or destroy them while they are drying.