Doric-style columns are like those found in the Parthenon in Greece. Doric columns do not have a base, and therefore the shaft sits directly on the floor. The column's shaft is fluted, and the capital has a decorative pattern.
Ionic-style decorative columns to cover posts, have a slightly more narrow shaft, a decorative base and a capital that looks like ram's horns. This type of covering may be slightly tapered, where it is thinner at the top and has a larger diameter around the bottom of the shaft. Ionic-style columns usually have 24 flutes.
Tuscan-styled columns are smooth and non-tapered, and can be round or square. The capitals on Tuscan columns are also more simple and do not have ornate designs in them. Tuscan columns will also have a base that is simple in design.
Corinthian columns are most commonly seen in more ornate Southern homes. This style of column has fluting along the shaft of the column and several layers of leaves on the capital. The base of the Corinthian column is also more ornate as it is taller and has more decorative designs in it than the other style of bases.
Outdoor decorative columns that go over posts are most often used on front porches, outdoor sitting areas and patios. Decorative columns for outdoor use are normally made from PVC and simply wrap around the post. The PVC is low maintenance and will not be affected by weather. These PVC wraps come in all of the different column styles.