How many shims can be placed behind a shelf angle before it is a problem? Does the size of the shim matter? What should shims be made from?
Shims installed at connecetion bolts for shelf angles must extend the full height of the angle. Otherwise, angles may be over stressed and rotate too much. Shim width and thickness are less important. Shims typically are about 2 inches wide; their thickness will vary based on need. Whenever possible, use thicker shims rather than multiple shims, but avoid shimming more than 1 inch. If multiple shims are used, the bolt must be tensioned to develop enough friction to prevent slippage. If slippage occurs, bolts may fail in bending or the angle may shift downward. Some manufacturers of metal inserts limit the amount of shimming. Shim materials should resist corrosion and not compress or creep noticeably under expected loading. Galvanized steel shims commonly are used for this purpose.