A pergola is a horizontal lattice-work supported by four or more posts or columns. Plants are trained to crown on the roof of the pergola for attractiveness and to add shade. The designs of pergola can be vary. One example of the designs is modern pergola designs. In modern pergola designs, you’ll also get to see vinyl, aluminum and others as materials in its construction. Then, in most modern pergola designs, a masonry support system can be installed as well. In either case a footing is needed for each column. Larger structures will need more posts, located along the outside edges for additional support.