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How to Build a Triangular Pergola

Jonah Morrissey

Pergolas define patios and sitting areas within outdoor living spaces and provide places for climbing plants to grow. A standard pergola is square or rectangular. Make your pergola stand out from the rest by building it in a triangle shape. Triangular pergolas are especially good for accenting a corner of an outdoor living space. Climbing plants can provide shade and add privacy to a triangular pergola. Plant climbing plants on two sides and leave the third side open for entry.

Lush foliage grows along a pergola.
  1. Cut a 45-degree angle with a miter saw on each end of the six 2-by-4s. The 45-degree angles will allow the boards to form an equilateral triangle. Place three of the boards together to form an equilateral triangle. This will be the roof of the pergola. Fasten the boards together using a screw gun and 3-inch coated deck screws. Assemble and fasten the other three boards in the same way. The second equilateral triangle will be the leg support frame for the pergola.

  2. Position the pergola roof in a work area. Place one of the 72-inch posts on an inside corner of the roof. The corner of the post will fit flush against the inside corner of the roof. Fasten the post to the roof by screwing through the roof boards into the post. Use a screw gun and 3-inch deck screws. Do the same with the other posts in the other two corners of the pergola. The posts will be the legs of the pergola.

  3. Lift up the leg support frame and place it over the three legs of the pergola. Allow it to slide down and rest against the roof. Measure up 24 inches from the bottom of the roof on each of the legs. Mark these measurements. Raise the leg support frame and hold it at the height of the pencil marks. Fasten the leg support frame to the legs with a screw gun and 3-inch coated deck screws. Screw from the outside of the leg support frame into the legs. Use two screws per joint.

  4. Position the two latticework panels on a work surface so that they are touching to form one large latticework surface. Lift the pergola, still upside down, and place it on the latticework panels. Center it so that the triangular outline of the roof fits entirely on the latticework. Draw along the outline of the roof with a pencil. Take the pergola off of the latticework panels. Place the latticework panels on sawhorses. Use a jigsaw to cut along the pencil lines. You should now have two latticework panels that go together to form a triangle the size of the roof.

  5. Lay the pergola on its side. Align the two latticework panels against the roof. Make sure that the panels are flush with the sides of the roof. Use a hammer and finish nails to fasten the panels to the roof. Space the nails every 2 to 3 inches.

  6. Flip the pergola upright. Move it to the section of the yard where you would like to use it. Prepare a place for the plants on two sides of the pergola. Cultivate the soil with a trowel. Plant climbing plants on the two sides according to the plants' specific planting instructions.