Posts are usually made from 4-by-4 inch or 6-by-6 inch lumber and at least four posts will be needed. Length requirements and actual counts of other lumber will vary depending on the design and size pergola you select. Support beams attach to the posts and are made from 2- by 6-inch lumber. Sometimes, a decorative curve is cut into these members with a saber saw. Cross beams, which span from support beam to support beam, are also made from 2-by-6 lumber. These, too, often receive decorative curves. Slats run perpendicular to cross beams and are made from 2-by-4 lumber. Diagonal braces are cut from 2- by 6-inch lumber and mount to the support beams and posts.
Galvanized nails or screws are needed to secure cross members and slats. Weather-resistant lag bolts and washers are used to secure the support pieces to the posts. In some communities, local building codes may also call for the installation of hurricane clips to provide additional support in high winds. Made of metal, these clips have two flat mounting surfaces at 90 degrees to one another. If mounting the pergola to a concrete pad or existing concrete structure, an anchor base and anchor bolts are necessary. The anchor base mounts to the concrete and is secured in place with an anchor bolt.
Bags of quick-drying concrete mix are poured into holes that will accept the posts. Gravel may be placed at the bottom of the hole to ensure proper drainage below grade. Quick-drying concrete requires no mixing and can be poured into the hole dry, then water added to activate the mix and set it up firmly around posts. If concrete will be poured below and above grade, cardboard tube forms (also called concrete pier forms) are needed to form and hold the concrete while it dries.