Although it is more expensive, cedar is also a good choice of wood because of its natural preservatives that decrease decay. The exact size of concrete masonry units fluctuates widely among manufactures, although most concrete masonry units are between 4" to 12" wide, 4" to 8" high, and 4" to 8" deep. units in comparison to stone or brick is that they cost less and are available in predetermined sizes that are often more easily and quickly installed. • construct trellises and overhead structures of many designs and openness (Figures 12-69 and 12-70). The dimensional sizes of wood used in landscape structures vary more widely than sizes of wood used for pavement. The lightweight quality of wood and its ability to be easily cut into any dimension give it great flexibility to create fences of various heights, material patterns, and openness (Figure 12-68). Other types of wood may also be used for structures if they do touch the ground. A distinct advantage of wood is its ability to be painted or stained, thus giving it a wide range of color and finish possibilities. Concrete masonry units can be used to:
• construct retaining walls, free-standing walls, and steps. Concrete masonry units (CMU) are precast concrete blocks that are prefabricated in specific sizes and shapes. • repeat house colors in the landscape. • repeat the color and appearance of precast concrete pavers (assuming that a given manufacturer makes both). Colors vary, with shades of gray, tan, and brown being most common. • provide colors not available with stone or brick. The advantage of concrete masonry
Figure 12-66
Examples of precast concrete block walls. Most wood used for landscape structures is pressure — treated wood, especially if it is in contact with the ground. The finish also ranges from clean, straight edges to rough, tumbled surfaces.
