What is it and how is it different from Rammed Earth?

Like Rammed Earth, Adobe is an ancient earth building method.   The adobe method uses large, sun-dried bricks to construct walls in a masonry style.   Bricks are laid up in courses with thick layers of adobe mud mortar between each course and between the bricks of a course.   As with other masonry construction methods, adobes offer a great deal of flexibility in design options.   Round or curved wall sections, arches and vaults are quite common in adobe buildings.   These features can be more difficult and often impractical to achieve with rammed earth construction.

Unlike rammed earth, which often creates a pleasing, even artistic finish in its 'raw' form, adobe walls are not typically considered attractive in their raw form.   Adobe walls are almost always covered with mud stucco on exterior surfaces and a plaster finish on interior surfaces.   These finishes can be left natural or painted according to the tastes of the client.   The finishes can also be applied thick or thin to smooth the appearance of the course of blocks or to accent them.   Mud stucco and plaster offer their own pleasing aesthetic effects, but also typically mean some additional maintenance over the life of the structure.   Idaho Earth Builders has access to alternative, soil-based finishes that are purported to be easier to apply and perform better than traditional mud stuccos and plasters.   Please contact us if you're interested in learning more about these options.

Despite their differences in composition and construction methods, Adobe and Rammed Earth perform equally well as thermal mass features - which is to say, they are both excellent thermal mass solutions.

Tell me more about Adobe

Adobe 'bricks' differ from common bricks in a number of ways.   Adobe bricks are commonly referred to as blocks.   The blocks are quite large: 8"w x 12"l and 10"w x 14"l being two common sizes.   Regardless of length and width, blocks are typically 3½" or 4" thick.   Adobe blocks are also sun-cured whereas common bricks are typically kiln fired.

Adobe is a product of its environment.   That is, adobe making originated in those areas where the raw adobe materials where readily available. Adobe blocks were made using a naturally occurring soil mix that just happened to be excellent for the purpose of making sun-dried bricks.   The soil was dug on site, mixed with water to create a thick mud, poured into forms or shaped by hand into 'loaves' then left to dry in the sun.   In the absence of a naturally occurring suitable soil, combining the right ratio of aggregate, sand and clay can create an appropriate soil.

Frequently, traditional adobe makers - adoberos: ah-do-bare-ohs - added straw to their mud bricks.   It was thought the fibrous material of the straw added structural strength.   While the presence of straw can help hold adobes together if they begin to weather and break apart, a well made adobe doesn't need such additives and contemporary adoberos no longer include straw in their mix.

As adobe making matured, adoberos began to add materials to make their adobes more water resistant - a process known as 'stabilization'.   Common methods of stabilization are to add lime, Portland cement or asphalt emulsion.   Both lime and Portland cement are dry mix stabilization options meaning they are added to the soil mix before the water is added.   They tend to have little effect on the color of the adobes, lightening them slightly.   Asphalt emulsion is a liquid stabilizer and is added along with the water.   As might be expected, asphalt emulsion tends to darken the adobes considerably.   This should be taken into consideration if the finished wall is to be left raw.

Note to our Adobe customers:

Idaho Adobe Works (a partner company of Idaho Earth Builders ) manufactures only stabilized adobe blocks.   As mentioned above, adobe blocks are sun-dried and typically require 4 to 6 weeks curing time before they reach full strength.   Presently, Idaho Adobe Works provides adobe block only on a custom order basis.   A minimum of 8 weeks lead-time is necessary to plan for the manufacture, supply and delivery of an adobe block order.   If the interest in adobe blocks is adequate to support a continuous adobe manufacture operation this lead-time will naturally shrink and perhaps even be eliminated.   We appreciate your understanding and patience.