Build a tree bench

The legs are tapered for good looks. Draw the angled profile on the inside face of each one according to the plans. I cut the tapers using a bandsaw, although you could use a jigsaw or even a handsaw for roughing out the shape. Use a stationary belt sander or a sharp hand plane to clean up the edges.

Dry-fit the legs and rails in position around the tree, then use a weatherproof adhesive such as polyurethane glue or Type II or Type III PVA glue for permanent assembly of the parts around the tree trunk. All main bench parts need to come together outside, and polyurethane is my favourite glue for outdoor use. Apply it sparingly, first dampening the surfaces with water from a spray bottle. Polyurethane adhesives need a bit of moisture to cure.

Clamp the rails and legs together until the adhesive has cured, then enlist a friend to position the assembly in the correct spot. Once you're satisfied with the location, mark the position of the legs on the ground, then move the frame far off to one side. Next, it's time to install one round concrete paving brick (sometimes called a “paver”) in each of the leg locations under the tree you marked earlier.

Use one of your bricks as a template, then remove the existing sod from each leg location. Create four depressions, one for each brick. Adjust the depth of the brick pockets so all four pavers sit in a level plane. A level, set on the edge of your straightest 2x6, will show how close you are. A couple of blocks of scrap wood set on the pavers allows this level line to clear any bumps of soil that exist between them.

Once all four bricks are level, remove the rest of the sod from under the bench and cover the whole area with cedar mulch to a depth of about three inches.

Next, cut the long, medium and short joists to length from pressure-treated 2x6s. Measure and mark the location of the longest joists on the top of the rails, then install them. I used three 3 1/2" ceramic-coated screws driven through the rails into the ends of the joists. Measure, mark and attach the medium and short joists in the same way. Finally, cut the diagonal joist brackets with 45º ends, and attach them to the joists with screws.

Making the platform
The bench platform is made from 5/4 cedar decking. This is one of the only types of standard lumber that measures a full one inch thick, perfect for the top of this project and many other outdoor applications. Cut the boards to length, except those that must be shortened to accommodate the tree. Position the first one so it overhangs the edges of the legs by one inch. I marked all screw locations so they all line up. On this project you'll be looking at the screws all the time, so any misalignment really stands out.

Before you fasten down any of the platform boards, try them all out first. You don't want any spacing surprises when you reach the tree or the other side of the bench. Beyond that, the boards that intersect the tree must be custom-fit around the undulations of the trunk. Use a couple of 1/4"-thick spacers to regulate board spacing.