This arbor is easy on the pocketbook and a snap to build. In fact, if you like, you can eliminate most of the cutting by asking the lumberyard to cut the wood to length for a small fee.
Choose arbor-enhancing vines, such as annual morning glory, cypress vine, or thunbergia, for easy color from seed that lingers until frost. Compost annual vines after frost knocks them down.
1. Choose the wood. Build the arbor from rot-resistant wood. Cedar and redwood are excellent choices for minimal maintenance, and both weather beautifully. You also can use pressure-treated pine or fir, though you'll have to check carefully for warped pieces when purchasing the wood.
2. Dig holes. Measure placement of the four main 2x4 posts, and dig four holes 18 inches deep. Fill with 6 inches of gravel for drainage to prevent the wood from rotting.
3. Cut lumber to length. The upright posts (A) come in 8-foot lengths and do not need to be cut. Cut the four 1x4 top rails (B) into 7-foot-3-inch lengths. If you wish to add the optional 1-inch-diameter decorative hole, use the following trick: Before cutting a rail to length, draw a line with a pencil where the 30-degree cut and optional decorative hole will go. Mark and drill the hole in the proper location with a 1-inch flat bit, then cut off the end along your marked line.
4. Cut spindles. If you did not purchase precut deck spindles, cut the thirteen 2x2s (C) to 3 feet 6 inches each using a 45-degree bevel on both ends. (We beveled 2x2s in the arbor shown in the photograph. The arbor in the illustration is shown with precut spindles, sometimes called deck spindles, which are already cut and beveled.) Cut the common lath (D) into 24 pieces of 3 feet each.
5. Assemble the sides. There are a number of ways to assemble the trellis, but the easiest is to take the four uprights (A) and lay them on their narrow sides on a flat surface and with the ends flush. Push them together side by side. Using a square and pencil, measure and mark the location of the lattice (as indicated in the illustration) on all four sides facing up.
Assemble the sides of the arbor by laying two of the upright post pieces on the ground exactly 2 feet apart at their outside edges. Then nail on the lath pieces almost the way you would construct a ladder. (For durability, use construction adhesive at all joints.) Making sure the frame remains square and properly spaced during assembly, nail the bottom lath piece and then the top lath piece. Continue with the remaining six pieces of horizontal lath for that side of the arbor. Tip: If the lattice cracks, predrill holes before nailing.
After the horizontal lattice is installed, nail on the diagonal pieces (E). Repeat the process to assemble the other side of the arbor.
Set the two assembled ends into the holes, keeping them level, square, and properly spaced. Tip: Temporarily tack two 2x2s or other pieces of wood across the bottom of the trellis front and back to keep everything square. Fill hole with soil, and tamp well with your foot.
6. Assemble the top. Lay the four top rails so narrow sides face up. Using the square, measure and mark the spacing (4 1/2 inches apart) for the 13 top pieces (C).
Install the marked top rails (B) using three 2-inch screws per joint. Check for square. Using the marks on the top of the top rails, install the top 2x2s (C) with 3-inch screws. Tip: For easier installation, predrill holes in just one of the 2x2s, then use it to measure and mark the holes on the remaining 2x2s. If using, screw in the optional decorative brackets with 1-inch screws; fill holes with the manufacturer's wooden plugs.
7. Finish. Give the arbor a coat of white exterior stain as we did, or let it weather. To paint, first coat with primer followed by exterior latex.