Frequently asked questions

What is a Compressed Earth Block?


A CEB is a machine made adobe. It is comprised of clay, sand, silt and gravel. The CEB can be stabilized with portland cement or lime. CEB sometimes don’t need gravel, other times gravel is needed to increase the strength of the block. There are many factors that are involved in the making of an Earth Block.




What Type of Foundation is Required?


Either traditional footing and stem wall or rubble trench. The depth and the amount of reinforcement will be dependent on local building codes.




How tall can a CEB building be?


There are many multi story adobe and CEB buildings around the world, however the USA and other countries are limited to 2 stories.




How much soil is required?


Soil amounts depends on the thickness of your wall. A general guideline is between 90%- 94% of a CEB is the soil/sand mix. 1 ton of soil will get you about 50 blocks.




How do I finish the Surface of a Compressed Earth Block wall?


The blocks can be left raw on the inside. You can be left unfinished on the outside as long as the blocks are highly stabilized, (10% or more portland cement.) Exterior finishes can range from a clear sealer to a limed plaster to cement stucco. For interior finishes we recommend clay to preserve the breathability of the wall. DO NOT PAINT.




Can a CEB wall stand up to seismic activity?


Yes, as long as the wall is appropriately reinforced. The 3 major reinforcement systems are height to thickness ratio, inclusion of bond beams, vertical and horizontal rebar, and the mesh basket.




How much does a CEB wall cost?


Obviously it depends. A CEB wall is similar cost to any other masonry wall in your geographic region. CEB walls can vary in thickness and stabilization. A good stabilized 10 by 14 inch block costs between $2.95 and $3.45




Are compressed earth blocks water resistant?


Yes, if stabilized. Portland cement or lime can be used in the mix to combine with the clay and sand to provide water resistance. The stabilizers combine chemically with the ingredients to provide water resistance.




Can I use any type of soil?


No. The soil must have ideally between 10% - 30% clay. The soil must me screenable and nor can it be organic matter. The soil should be relatively dry but adding 10% moisture helps hold the block together.




Why do I need clay in the soil?


Clay is the binder that holds the CEB together. There are 4 ingredients to soil anywhere in the world. Clay is unique in that it has a negative electrical charge. The clay combines with the other ingredients in the block under pressure to produce the finished CEB.




Why cement, lime, or another type of binder?


We use binder to inhibit the blocks from water damage. Binder performs a chemiacal reaction with the ingredients of the soil to promote stability against water. Stabalized blocks are water resistant. Stabilized blocks increases the structure, PSI and strength of the block.




What is the density of a compressed Earth Block?


The density of a CEB is 120 pounds per cubic foot. The resistance varies from 500 to 2,500 pounds per square inch. CEB’s are very dense.




How Much Moisture is Required for CEB’s?


Roughly 10% moisture content is ideal for compression in most instances. One of the advantages of CEB’s is the minimal usage of water.




How Long does an Earthen Building Last?


If stabilized and well built an earthen building can last centuries. Earth Blocks are not subject to fire or termites because they’re stronger and not comprised of ingredients that are edible. An Earthen structure called Touse Pueblos is about 1,000 years old. The structure of Earth Blocks allows for this.




Why do I need Clay in the Soil?


Clay is the binder that holds the CEB together. There are 4 ingredients to soil anywhere in the world. Clay is unique in that it has a negative electrical charge. The clay combines with the other ingredients in the block under pressure to produce the finished CEB.




What is the Mechanical Resistance of an Earth Block?


The code is 300 PSI, however we average about 1,500 PSI. The strongest I’ve ever made 2,560 PSI.




Can Earth Blocks be used for Good Sound Insulation?


Yes, earth is considered very good sound insulation. Earth Blocks are exponentially quieter because our blocks are denser and don’t allow for sound to pass through.




Are Earthen Structures Strong?


Earthen walls are very strong! The blocks are bullet-proof and structurally sound for any type of roof. They are virtually hurricane-proof. If properly reinforced, they are also highly seismic resistant.




How do CEB’s Perform in the Rain?


The block perform extremely well if properly stabilized. Earth Blocks can be heavily stabilized with 10% or more portland cement, or they can be moderately stabilized with 4-5% portland cement. They can also be unstabilized, which deteriorate if exposed to water. Unstabilized blocks can be protected by plaster, roof overhangs, or a stem wall.




How do Earth Blocks Perform in Temperature Swings?


CEB’s perform very well under swings because of the FlyWheel effect. Due to their high density and ability to absorb and release water vapor, the blocks moderate the interior temperature in the building as the temperature swings.




How do Earth Blocks Perform in Tropical Climates?


It is true that the temperature effects in a tropical climate are not as significant as any climate with warm days and cold nights. However, CEB’s are still as effective or more so than any other mass wall in augmenting human comfort.