Typically, a jacal would consist of slim close-set poles tied together and filled out with mud, clay and grasses. More sophisticated structures, such as those constructed by the Anasazi, incorporated adobe bricks—sun-baked mud and sandstone.
Jacal construction is similar to wattle and daub. However, the "wattle" portion of jacal structures consists mainly of vertical poles lashed together with cordage and sometimes supported by a pole framework, as in the pithouses of the Basketmaker III period of the Ancestral Puebloan (aka Anasazi) Indians of the American Southwest. This is overlain with a layer of mud/adobe (the "daub), sometimes applied over a middle layer of dry grasses or brush which functions as insulation.