How to Build an Octagon Gazebo

An octagon gazebo provides homeowners with a beautiful means of enjoying their landscape. The plans for an octagon gazebo can be purchased from a home improvement store or online from a variety of websites. The gazebo should take about three days to build. You will need the help of family or friends to complete your project.

Tools and Materials

  • Wood
  • A saw
  • A tape measure
  • Spray chalk
  • An auger
  • Concrete mix
  • A shovel
  • A wheelbarrow
  • A level
  • Decking screws
  • Joist hangers
  • Nails
  • Cap platesA
  • A screwdriver
  • A hammer
  • A ladder
  • Prefabricated rafters
  • Prefabricated steps
  • A stapler
  • Roofing felt
  • Shingles
  • Roofing nails
  • Protective eye wear
  • Work gloves
  • Work boots 

Step 1 – Safety

Be sure to put on protective eye wear, work gloves and work boots.

Step 2 – Choosing a Gazebo Plan

Purchase an octagon gazebo plan from a qualified designer. Be sure the plan provides all of the necessary material measurements for the project.

Step 3 – Obtaining the Wood

Visit your local hardware or lumber store to purchase the wood for your gazebo project. Speak to a professional about your project and get some advice on the best wood and the best prices for your plans. The store should be able to cut it into the lengths you need.

Step 4 – Choosing a Location for your Gazebo

Decide on the location for your octagon gazebo. Use the measuring tape and spray chalk to mark the outline of the space for the gazebo base. If necessary, remove any plants or rocks from that space. 

Step 5 – Installing the Posts

Use the auger to dig the post holes. The holes should be 30 inches deep. Read the instructions on the concrete mix packaging. Mix the concrete in the wheelbarrow. Shovel the mix into one of the post holes. Place a post into the concrete. Use the level to even out the post positioning. Continue with the other posts. Allow the concrete mixture enough time to dry completely.

Step 6 – Installing the Deck

Use the decking screws to secure the deck planks to the outside of the posts. This will create the deck frame. Level all of the planks as you work. Install the center post for the deck. Install the joists that will run from the center to the frame. Once again, use the deck screws to secure the joists and make sure they are all level. Install the cross supports and then the deck floor. 

Step 7 – Locating the Steps

Decide on the location for the step to the gazebo. Use the concrete mix to make a slab for the steps. The slab should be located two inches further than the width and length of the steps. It should also be about four inches thick.

Step 8 – Building the Roof Supports

If possible, purchase prefabricated roof rafters. The rafters measure half the distance from one post to the post on the opposite side of the gazebo. Attach cap plates to the post tops. Secure two opposite rafters to the roof center. This will form a truss. Install the truss on the top of the gazebo. You will need someone to help you with this task. Position the truss and nail it into position onto the cap plates. Secure the the rest of the rafters. The exposed ends of the rafters should be protected with fascia. 

Step 9 – Installing the Roof Shingles

Use a ladder and climb up on the roof. Install the sheathing onto the rafters. Use the stapler to secure the roofing felt. Secure the shingles with roofing nails.

Step 10 – Finishing the Gazebo

Secure any rail sections to the posts. Install the steps in the location you have chosen.