Before building a pergola, it’s smart to plot everything out on paper first. If you’re building it on the ground, you’ll need to mark and dig holes for the corner posts at least 3 feet deep (even more if you live in a deep frost area). For extra support, you may want to frame and pour concrete footings for the posts to sit on. Make sure the posts are level and placed at correct intervals before filling the holes with quick-setting concrete.
A hammer drill, some quick drying epoxy and anchoring bolts are the tools you’ll need. Several types of materials can be used to build your pergola. Pressure-treated pine will hold up against the elements, but also can be heavy and difficult to use. Cedar and redwood are natural woods that resist decay, are easy to work with and age to a pleasing gray color. Mahogany is a tight-grained hardwood that resists pests and rot. When treated with marine oil, it has the appearance of teak. You can also use composite materials, which hold up well and are virtually maintenance free.
Secure metal braces to the stone or concrete surface for your corner posts. The next task is to cut four 2x8 support beams. Using a jigsaw, decorative features can be cut into the ends. When attached to the corner posts, the beams should be even and level.Use galvanized carriage bolts to secure the support beams to the corner posts. Countersink them on both ends so they will be flush with wood. Use #10 screws to secure the crossbeams to the support beams and the slats to the crossbeams.
Next comes a row of cross beams, notched with a jigsaw and fitted perpendicular to the support beams (Image 1). Add a row of slats notched and running the opposite direction (Image 2). For extra support, diagonal braces can be attached between the beams and corner posts (Image 3).
When finished, you can paint the wood, or stain and seal it with a waterproofing sealant. Since over-spraying can leave a residue on your house, it’s better to apply the stain with a roller or brush. To keep your wood deck from turning gray, you’ll need to purchase a sealer or stain with an ultraviolet (UV) protecting chemical. Add some plants and patio furniture and your garden pergola becomes a warm and cozy place to relax.