Cordwood masonry or what is sometimes called "stackwall" or "stovewood" is a form of house construction that consists of laying whole or split wood, width-wise in a bed of mortar. When looking at a cordwood wall, log ends are the only part of the wood that are visible. The wood actually rests on two mortar beds that are each about 4" thick - one mortar bed is the outside of the wall and the other bed is the inside wall. In between each bed of mortar, insulation in the form of lime treated sawdust or other insulative materials fill in any empty space between the logs and mortar. The thickness of the wall is determined by the length of the cordwood used. Typically, walls are anywhere from 6" to 24" thick depending upon the builder's need for energy efficiency.