Once the posts have been set, the rest of the structure can be built in a half day. Widely spaced 1x3 braces allow room for robust plants to climb, but are far enough apart to discourage small children from using the trellis as a jungle gym.
Choose wood that will last in your climate. If you plan to paint the structure, pressure-treated lumber is an affordable choice. 1x3s are needed for side braces. If your lumberyard does not have 1x3s, they should be able to rip 1x6s to size for a modest cutting fee. In addition to basic carpentry tools, you will need a posthole-digger, a shovel, and something in which to mix concrete -- a deep wheelbarrow or plastic mortar box. Rent a power miter saw if you are not confident about making accurate 45-degree cuts on the 2x4 rafters. With a posthole digger, excavate postholes that extend below the frost line or at least 24 inches deep. Pour in 2 to 3 inches of gravel. This keeps the bottom of your posts from direct contact with the soil.
- 4 4x4x12-foot for posts (10-footers will work if your postholes are shallower than 24 inches)
- 2 2x4x8-foot for top plates
- 2 2x4x12-foot for rafters
- 2 1x3x14-foot for side pieces
- 2 1x3x10-foot for roof pieces
- 1 pound 3-inch galvanized deck screws
- 2 pounds 1-5/8-inch galvanized deck screws
- Concrete and gravel for the postholes
- Scrap wood for temporary braces and stakes
Continued on page 2: Step-By-Step