Metal lath should be hung horizontally. Joints between panels should be staggered in a standard brick-laying pattern. The seam between the first and second panels on the bottom of the wall should fall in the center of the panel placed immediately above them.
Expanded metal lath has a diamond shaped mesh. In order to form a proper holding base for stucco or plaster, the pockets formed by the mesh should face upward. The mesh should feel rough if you run your hand downward across it and smooth when running your hand upward.
Attach the lath to wood framing with 1-1/2-inch roofing nails. Nails should be 16 inches on center with no more than a six inch vertical spacing. When attaching lath to wood sheathing, 1-1/2 inch staples with a 3/4-inch crown should be used.
Lath should be wire-tied at nine-inch intervals on edge and end laps to prevent separations.
In order to allow the plaster or stucco to properly adhere to the lath, a minimum 1/4-inch gap should be maintained between the lath and the surface of the wall.
Lath can be cut to size and shaped with shears. A standard circular saw with a metal cutting blade can reduce cutting time on a larger job. Always use eye and hearing protection when cutting metal with power tools to prevent serious injury.
--------------- adapted from //www.ehow.com