How to Build an Arbor with Built-in Benches

Project overview: Benefits, materials and cost

This corner arbor turns empty space on a patio or deck into a leafy green sanctuary. Use it to create shade and privacy, to screen an unattractive view, or to add color to a concrete patio or wood deck—even a second floor deck. Our arbor is covered with a tropical vine called mandevilla, a great plant for walls, trellises and arbors.

The entire arbor is made from pressure-treated wood, but coating it with a penetrating stain and hiding the fasteners makes the project look more like a piece of furniture than decking. The stain will also help keep it from cracking and warping as it weathers.

Using pressure-treated wood keeps the cost reasonable too. All the materials for this project cost $250. The project can be built over two weekends—or one if you don't stain it.

Treated wood lasts almost forever, but it can be gnarly to work with. Take your time picking through the lumber pile for good pieces. Look for dry (lighter) pieces without too many knots. You'll need straight pieces for the uprights and benches, but you can use nice-looking, moderately warped pieces for the planters. Let the lumber sit for a few weeks so it all shrinks uniformly. Remember to put the best sides out when you assemble the planters and benches.

Step 1: Assemble the planter boxes

Each planter box is made by alternating 10 short and 10 long lengths of 2x4 and joining the inside corners with 2x2s. The overall size is based on 16-in. square plastic planters (actual size 15-1/2 in.) widely available at home centers. If you can't locate that exact size or you prefer a different style, make the planter supports (D and E) larger or smaller, or build a base inside the planter box to support the planter. You can also change the size of the planter box.

Use a stop block to cut all the pieces quickly and accurately (Photo 1). Set three long and two short pieces against a square clamped to the worktable, using short spacer blocks for alignment. Predrill the 2x2 corners with a No. 8 countersink bit to avoid splitting the wood (Photo 2). One 2-1/2-in. screw per 2x4 is sufficient.

Make a front and back for each planter box, then set them upright and join them with interlocking 2x4 pieces (Photo 3), again attaching them from the inside. Although screwing from the inside is fussier, it enables you to avoid the cracks that often occur when pressure-treated wood is screwed near the ends.

Finally, screw the bench supports on (see Figure A in “Additional Information” below). Stain the planter boxes and all the other pieces now to avoid drips on the deck or patio. It's also easier to coat all the bench pieces on all four sides at this stage (Photo 4).

Note: You can view and download the Cutting List, Materials List and Figure A in “Additional Information” below.

Step 2: Construct the benches

Clamp the front and one of the sides of the bench to a square edge. Clamp the first set of spacers and the first 2x4 slat to the front piece, then drive two 3-in. screws through the slat and the spacer into the front piece. Continue fastening, clamping the slats in position to keep them aligned before screwing them in (Photo 5). Check to make sure the bench stays flat as you assemble it. Toe-screw the bench ends to the front of the bench, then drive two screws into the end of each slat (see Figure A).

Put the benches in place flush with the back of the planter boxes (Photo 6). Screw the benches and planter boxes together with four 2-1/2-in. screws, then screw on the planter supports inside the planter box with three 2-1/2-in. screws each.

Level the planter boxes if necessary, adding hidden 2x2s or 2x4s for legs (Photo 7).

Step 3: Assemble the trellis

Screw support blocks to the backs of the planter boxes 3 in. in from the corners, then attach the posts (Photo 8). Cut the posts 7 ft. long plus the distance (if any) the planter box was shimmed up, so that they sit on the ground but are level with each other at the top. Drive two additional screws into the posts from the inside of the planter boxes, but don't worry if the boxes are still a little wobbly—the top rail and cap lock everything together.

Set the top 2x4 rails on the ground next to the posts, leaving a 1-1/2-in. overhang at the outside ends. Mark the position of each post on the top rail, then clamp the rails flush with the top of the posts and fasten them with 3-in. screws to the posts and to each other (Photo 9).

Nail on the lattice, overhanging it 1-1/2 in. on the outside edges and butting the pieces at the corner (Photo 10).

Screw on the 2x6 cap pieces to finish the structure, mitering them at the inside corner and screwing the two sides together. Drop in the plastic planter boxes (from home centers or garden supply stores), fill with dirt, and plant with a mix of climbing flowers and vines.

Additional Information

• Figure A: Corner Arbor
• Corner Arbor Cutting List
• Corner Arbor Materials List