Build Your Own House With Compressed Earth Bricks

What Are Compressed Earth Bricks?

The concept is called Compressed Earth Blocks; also known by it’s abbreviation as CEB. These blocks are made by compressing damp earth with enough pressure to create a building material with very little expense. You’re not going to the nearest home improvement box store, buying your supply, and then paying for it to be delivered. You simply dig up the material, add some water, a stabilizer (lime or portland cement), mix the material and pressing them into the size that you determine. You can make large heavy bricks or small easily managed ones. These are super impressive. CEB are made from the same basic recipe as rammed earth. The biggest difference is you’re using a form to create small managable blocks compared to building forms and using a pneumatic tamper to create one solid wall.

Where Did The Idea For Compressed Earth Bricks Come From?

The original idea came from Raul Ramirez as part of a project for CINVA (Inter-American Housing Center). The goal was to allow poor people a chance to build their own home using a simple machine to press earth into bricks. Those bricks are referred to as Compressed Earth Bricks or CEB as an acronym. Originally, a single CINVA press could build a house with about $180 USD. It allows one or two people to build a home on their own with little money and resources. These presses have had modifications done to them, but most aspects have changed very little. The biggest change was the creation of machines that could press bricks at volume. Those machines tend to cost upwards of $20,000 USD. For most people, this defeats the entire reason to use compressed earth brick. It’s possible to rent one of these machines, but it’s very difficult to find one. If you’d like to do this yourself and you’re on a budget, consider having someone weld you a CINVA press of your own.

Here’s a video showing a version of the CINVA press in action:

How To Make Compressed Earth Blocks

Step 1: Testing Your Dirt

You dig up the dirt in the area you plan to build. A good idea is to use the material excavated while building your foundation. Unless your land has a ton of hills and various elevation, you will likely need an area to dig up all the dirt you’ll need. I plan to build a cistern right next to my house, so I’ll use that as my main source of material. Once you know where you plan to dig, test your soil. The easiest and most cost effective way to do this is to do the jar test. Fill a jar about half way with dirt, then fill the rest of the jar with water. Shake the crap out the jar making sure all the material has been dissipated in the water. Set the jar down and let the material separate. It will create layers. The heaviest material will settle at the bottom and the lighter stuff on top. Gravel and sand will be the lowest layer in your jar. The next layer will be your clay. Then silt and top soil. You don’t want much silt in your blocks, so make sure you remove the top soil prior to testing your dirt. If you notice you’re digging into new material that doesn’t match what you’ve already tested, repeat the test. It’s better to know what your working with than hope it all goes right.

Step 2: Mixture Your Dirt In The Right Proportions

You need to make sure you’re material has the right proportions of clay, sand, and portland cement. You want 60% sand, 30% clay, and 8-10% portland cement. Some people will tell state you can use less portland cement. As little as 4%, but my stance is this: You should always use the upper end of what is recommended. Especially for your house. If you’re building a seating area or something else then this isn’t as critical. Feel free to use less. You can use as little as 4% for those areas. Don’t skimp on your house! If your test show you have more sand than clay or vise versa, find another source on your property to gather whichever you need. Riverbeds can be a good source of sand if you have too much clay. In the worse case scenario, you’ll need to buy the extra material from a supply company. Don’t be afraid to test dirt from all over your property. One spot may have a lot of clay and another might have more sand. You can mix and match dirt to create the correct blend. Why Do You Need Portland Cement? You could build bricks and add straw as a binder, but it won’t be waterproof. You’ll need to add a waterproof plaster to the outside of your structure. Ever 5-10 years, this will need to be redone to protect your building. By adding portland cement, you are effectively making a brick that is “stablized” and waterproof. You can still add a plaster coating for aesthetics, but you won’t have to worry about the blocks becoming unstable. The cement also makes the bricks more solid and removes the need for the typical process of having to fire bricks to cure them.

Step 3: Mixing In Water

Don’t go crazy with this. You aren’t making mud. You just need enough water to bind everything together. You’ll be adding just enough water to get to about 10% moisture content That’s not very much. It shouldn’t be muddy or sticky. Add a little water and test it by taking some out and making a ball of dirt in your fist. Does that ball of dirt stay intact when you stop squeezing it or does it simply fall apart? Eventually you’ll get a feel for how much water to add.

Step 4: Compressing Your Earth Into Blocks

You can do this with man power or machine power. Originally the blocks were designed to be made on site by poor people in Columbia using a press called a Cinva press. The original Cinva press was designed in 1952 by Raul Ramirez of the Inter-American Housing Center in Bogota, Columbia. Raul Ramirez was a Chilean Engineer who’s goal was to help “neglected families, especially those in the farmlands, with a manual tool of work which, operated by themselves, will permit them to erect the walls of their houses.” Based on Mr. Ramirez remarks, the best soil for use in cinva presses are 50-70% sand. He recommends crushing the material (often referred to as dirty clay or sandy clay) and sifting it through a number 4 sieve. These presses can be made using metal welded together or even wood. It is essentially a lever that places pressure into the form, compressing the dirt. Once you get the basics of the design, you can modify them to suite your own needs. There are open source designs available for free. A popular one is called “The Liberator”. Unlike the slow processes of making adobe bricks, a couple people could crank out dozens; possibly even hundreds of these compressed earth blocks each day. One person can make these bricks on their own, but two people is perfect. One person handles the mechanical needs (ie. compressing and opening the form, then pushing the block out). The second person grabs the brick, sets it to the side, and refills the bin for the next brick. The process can be speed up using machines, but they are expensive and few people building their own home need to spend that much money.

Step 5: Curing Your New Compressed Earth Blocks

Because these are made using very little water and portland cement, they don’t need long to cure. It takes about two weeks to completely cure your blocks. Place your bricks on pallets and cover them with a plastic tarp to keep the humidity high. Portland cement needs moisture to cure properly and give you the best strength possible. Occasionally lightly spray/mists your bricks with water to make sure they don’t dry out. After about two weeks, your bricks are strong and ready to build with!

CEB and Mortar

Assuming you’re following our recommendations of using a stabilizer (portland cement), then a standard masonry mortar is appropriate. There are a variety of options from commercial manufacturers to making your own mortar onsite. If you choose to not use a stablizer, then you will need to cover the walls with a plaster to protect the bricks. It’s best to use a natural lime plaster if you choose to go this route. Ultimately, you won’t save money by skipping the portland cement within your bricks. In fact, if you’re in the United States, you’ll likely pay a lot more money for skipping that step. That’s mostly due to the fact that the proper lime needed to make a real lime plaster isn’t very common in the US. If you do find it, you’ll be paying between $50 and $100 per bag. Do yourself a favor and use the portland cement and cure it. Then use any standard mortar you can buy at the local hardware store!

Final Thoughts

Compressed Earth Bricks are an amazing resource for off-grid homesteaders. Even if you don’t plan to build your house with them, interior walls or accessory buildings are a possiblity. Not to mention the idea of building paths, patios, or even small walls are all possible with this technique. I plan to buy one or build one myself. For a few bucks worth of portland cement, the possibilites are limitless! As I use these on my own homestead, I’ll update this website and create videos for YouTube. If you build something, send me a link to pictures or videos. I’d love to see what you did!