What is the correct name for Earth Blocks?
Earth Blocks are commonly referred to as “Compressed Earth Blocks” (CEB) or simply as “Earth Blocks.” However, we have come across additional labels that include Pressed Earth Blocks (PEB), Compressed Stabilized Earth Blocks (CSEB), Earth Bricks, or Pressed Adobes. We refer to these hydraulically pressed blocks, whether stabilized or not, as CEBs or Earth Blocks because that is how they are referred to in code and they are the most commonly used labels. Back to Top
Is a CEB an adobe block?
Adobe blocks and CEBs look similar and have very similar thermal and structural values. We draw upon the historical use of adobe for determining the performance, longevity, and structural application of CEB. The difference between a CEB and an adobe is primarily in how they are made.
A CEB is a soil mixture with an approximate moisture content of 10% that is hydraulically pressed in a machine. Because the same mold is used to form each block, CEBs are identical in height and length, which allows the blocks to be laid in a wall with thin slurry or a minimal amount of mortar. With our CEB machine, we can adjust the width of the blocks from just a couple inches up to 10 inches in a few seconds. Typically, the compressive strength of CEBs is much greater then traditional adobes.
An adobe block, while utilizing a similar soil, is typically made with the addition of straw and mixed with water to a thick mud consistency. This mix is poured into forms and sun dried. A dry climate or at least a few weeks of very dry weather is necessary for curing.
Because CEBs do not require sun drying they can be made in colder temperatures and wetter climates. Both adobe and CEB have similar thermal, aesthetic, and structural qualities. Building code for adobe can therefore be applied to CEB. Back to Top
Is there a building code for CEBs?
Compressed Earth Block falls under the code for adobe. It appears in the Uniform Building Code (UBC) under “unfired clay masonry.” Adobe code also appears in the new International Building Code (IBC) and the Southern and Standard Building Codes under “adobe.” New Mexico has developed a code specific to CEB and can be found on our Code page.
What does “stabilization” mean?
“Stabilization” refers to the process by which a soil used to make CEBs is treated to make it more resistant to weathering and improve the compressive strength of the block. For example, the addition of a small amount (4-7%) of Portland cement or lime mixed into the soil prior to pressing, improves the block’s water resistance and compressive strength.
The term “stabilized” is defined in code to mean a block with certain admixtures that retains minimum strength requirements in water (i.e. compressive strength of 300 PSI). Saturation is defined as a minimum of four (4) hours of submersion in water as defined in ASTM D1633-00. Back to Top
Did we invent the CEB machine?
No, hydraulic earth block machines have been around for several decades. One of the first to be designed was the Cinva-ram, which is a hand-operated press that was first used by the PeaceCorps for housing projects in Central America and Africa. Today, CEB machines are operating around the world to provide both affordable and custom homes. Back to Top
Can CEB be used as a foundation or below grade?
No, CEB is not appropriate for areas that are in continual contact with the ground.
Can CEBs be left uncovered as the interior or exterior finish?
Once people see the natural beauty of a CEB wall, they often ask, “Do we have to cover them?” On the interior of a home they can be left exposed or finished with a decorative plaster. On the exterior, we recommend a render or stucco finish. There are CEB homes that have been sided with cedar, cultured stone, and dare we say-vinyl. Back to Top
Is CEB construction the same as rammed earth construction?
No, rammed earth walls are built with soil tamped into forms similar to poured concrete. CEB is more similar to brick construction with individual units; where as rammed earth is more similar to solid concrete walls. Like CEBs, rammed earth walls use clay/sand soils.
We build with CEBs because we find them to be more user- friendly and easier to make structural alterations and remodels with. A CEB cavity wall system also offers several insulating options. Back to Top
Are CEB homes found in cold and/or wet climates?
Yes, there are CEB homes and structures found in Iowa, Wisconsin, high altitudes in Colorado, and wet tropical climates like Central America. There are adobe structures in New York and it is reported that Paul Revere’s home in Boston incorporated adobe blocks. Back to Top
Are CEBs load bearing?
Yes, Earth Blocks can stand alone as your entire load bearing wall system. Back to Top
Can I use soil from my building site for the manufacturing of CEBs?
Yes, if your soil has a clay content between 15-30% with the remainder being primarily sand. We often take the soil right from the excavated foundation, mix it with a stabilizer, and make blocks. Back to Top
How do I know if my soil is suitable for making CEBs?
You can conduct simple tests at home and/or have a lab do a soil test to determine clay/sand/silt/organic matter content. You can also get a sample to us and we will test if for you. Of course, the best test is to make a few Earth Blocks with your soil and see how they cure. Back to Top
What if my soil is not suitable for block making?
If soil suitable for Earth Block making is not found at your site, it can often be found in the local area. We can also add sand or clay to your soil if it is low in one of these.
Can I build a two-story home with CEBs?
Yes, the code allows for two stories. However, there are much taller structures around the world that have been standing for centuries. The tallest existing structure is in South Yemen and is over 7 stories. Back to Top
Can CEBs be used in combination with other building materials such as wood framing, timber frame, concrete block, and straw bale?
Yes, all of the homes we build utilize other building materials such as wood framing for the roof. For example, we have used CEBs with timber framed structures and as interior walls for thermal mass in straw bale homes. Back to Top
Can CEBs be used for interior walls?
This is an excellent use of CEBs in a home built with CEBs or a hybrid home utilizing a combination of methods such as CEBs, frame, straw bale, rammed earth, concrete, or timber frame construction. This is because it provides a great amount of thermal mass to the interior environment of the home which helps regulate indoor comfort and temperature. Back to Top
How do you insulate a CEB home?
In cold climates we insulate CEB walls. This can be done in two ways. The first is to apply insulation on the exterior of the wall and typically involves nailing rigid foam insulation to the outside. The second method is to build a “cavity wall,” which is two walls with an insulated cavity in between. Cavity walls are our preferred method of building, because it allows the use of several different types of insulation, many of which are more “environmentally friendly” than rigid foam insulation. The cavity also provides a space for running utility wires. Back to Top
What is this going to cost me?
For detailed information about costs, please click here.