A rustic gazebo, clad in bark, with beams and boards slightly gapped, is a beautiful point of focus for a garden whose plantings spill onto paths, creep across arbors, and play outside the rigid lines of a formal garden layout.
This article uses applied geometry to construct the outline of an octagon and to create roof angles. Please refer to "Resources" for a complete discussion of additional methods to create the outline of a regular octagon, calculate miter angles, and use a plumb bob and spirit level.
Choose a point of origin. This will be the exact center point of your gazebo. Drive a metal peg into the ground at this point. Run survey string in a cross with 8-foot-long arms, centered on the metal peg. Drive wooden survey stakes into the ground at the end of each arm of the cross, and pull the string taut.
Stand on the center point and turn 45 degrees. Repeat Step One, bisecting the 90-degree angles created by the original string cross. All the wooden stakes should be 8 feet from the center point, and all eight angles from the point of origin should be 45 degrees.
Mix quick-drying concrete in a wheelbarrow, according to the directions on the bag. Remove only one wooden survey stake at a time, and dig a 2-foot-deep posthole at that point. Place one of the nine 6-inch-diameter round posts in the 2-foot-deep hole. Fill each posthole with gravel to help support the post. Fill the remaining space with quick-drying concrete. Remove the metal survey stake and place the ninth post at the exact center of the octagon to provide additional support for the main roof beam.
Place a spirit level on top of each post, and hang a plumb bob from it to ensure that the post is straight up and down. Adjust each post until it is level and the plumb bob hangs straight along the post. Brace each post upright if necessary until the concrete dries. Allow the concrete to set for several days before proceeding.
Measure the distance between posts, which should be about 6 feet. The total interior angle created by the joint of any two sides of the octagon is 135 degrees. Use a table saw with miter fence to miter the 1-inch edges of the plywood sheets to a 67.5-degree angle. Hang the plywood sheets between every two posts, butting the mitered corners together. Attach using 3-inch galvanized wood screws. Leave at least two sides of the gazebo open.
Decide on the pitch for your roof. Purchase a ready-made 16-foot-long truss that matches your desired roof pitch. Lay the truss in place across two opposite posts, making sure that the center post supports it. Attach two of the right-triangle trusses to complete the cross, using 6-inch wood screws. Turn 45 degrees and use the remaining four right-triangle trusses to create the second cross. All eight legs of the roof beams should create 45-degree angles from the point of origin to the walls.
Cut plywood sheets into isosceles triangles with the correct dimensions. Drill 1/8-inch diameter pilot holes every six inches along the trusses. Countersink all holes. Attach the plywood sheets to the roof using the 3-inch galvanized steel wood screws.
Use slab bark or cedar shakes to shingle the roof and walls. Attach bark or shakes to the walls and roof using 2-inch galvanized steel wood screws.