How to Build a Tree Bench Seat

Measure the thickness of the tree around which your tree bench seat will stand. Take the measurements at a height of 18 inches (where your bench seat will rest), and divide the number by 1.75.

Use your table saw to cut 1 1/4-by-6 inch deck boards to fit. For example, if your total diameter measures 35 inches, then each board should measure 20 inches in length. These deck boards will then serve as the seating surface.

Cut each end of the 1 1/4-by-6 inch deck boards to a 30 degree angle with a miter box and hand saw. Set the angles so the longer ends are all in contact with one another and the boards form a hexagon when laid end to end. The hexagon should enclose your tree and provide a structural outline for your bench.

Lay a full 1 1/4-by-6 inch deck board on a flat working surface. Place your cut board directly on top of it. Mark the size of the cut board onto the full board with your pencil. Use a table saw to cut the deck board to the markings. Lay your cut 1 1/4-by-6 inch board onto the flat working surface. Place three more uncut deck boards in line next to it so you have four parallel boards laying side by side.

Place a straight edge across the four 1 1/4-by-6 inch deck boards so that the 30 degree angle continues across all four. Mark the line with your pencil. The result should be four boards that get steadily longer as you move from one to the next. Repeat the process at the other end of the deck boards and repeat the process with five more sets of deck boards. These angle-cut deck boards will serve as your seating areas.

Lay your seat boards onto a flat surface in the shape they will take when assembled. Use shims to space the seat boards evenly and use your tape measure to gauge the size of your bench legs. Run the tape along the angled edge of one seat section, from the midpoint of its smallest unit, to the outside lip of its larger unit. The legs will run along this same path to provide the most strength possible.

Cut 2-by-6 inch decking with the table saw into 12 pieces that fit the measurement you recorded in Step 6. These will serve as your seat supports. Cut 2-by-6 inch decking boards into 12 pieces, each at 16 3/4 inches in length. These will serve as your bench legs. Use your miter box to cut the outside end of each seat support to a 30 degree angle.

Sandwich each set of bench legs between two seat supports, with the angle-cut ends coming to a point toward the center. Drill two pilot holes through each support and leg, and slide carriage bolts through the holes. Tighten each bolt and nut into place with washers placed on the inside and outside.

Stand three leg and seat support on a flat work surface. Lay your seat boards across the legs. Use the wooden shims to create even spacing throughout the seat boards, and leave 1 inch of overhang at the front edge. Drill pilot holes through the seat boards and into the seat supports below. Drive 2 inch deck screws into the pilot holes. Do not fasten the rearmost seat board in place yet.

Place the completed section of your bench around the tree. Finish installing the rest of the seat boards on location. Check that the bench is plumb all the way around once all the seat boards have been installed with a level. Add or remove soil from beneath the legs to adjust until level.

Cut six 2-by-6 inch boards to the same length as your rearmost seat boards with the table saw. These boards will serve as your bench back rests. Remove the rear seat board, and hold a back rest up to it so the two form a right angle. Use your power drill to make a pilot hole upward from the underside of the seat board, and into a back rest. Apply wood glue to the joint, and drive 3 inch deck screws into the holes Install the rear seat board onto the bench.

Drill a diagonal pilot hole from each back rest into the adjacent one. Seal the seam with wood glue, and drive 2 inch deck screws into the hole.

Measure to record the distance between each seat support. Cut strips of 1 1/4-by-6 inch deck board to this length and use your miter box to cut a 30 degree angle at each end. These will serve as your apron. The angled side should face inward when installed, and create a flat and continuous appearance from the outside. Drill pilot holes through the apron and into the seat supports behind. Drive 2 inch deck screws into the holes.

Sand and paint or stain the bench as desired.