How To Build an Octagon Deck
The most important thing to be concerned with while building an octagon deck is to keep it level and square. We recommend to start by setting the prenotched posts at each corner positioned at a 22.5 degree angle. Between each of these posts, you will install double flush beams. Make sure each beam is the same length and equidistant to the opposite side.

The perimeter framing will be flexible for you to adjust before adding additional framing. Use temporary supports to stabilize the frame while working. Once the deck perimeter is square and level, install joists using angled joist hangers to strengthen the octagon frame. Avoid installing joists to the corner intersections to prevent interfering with the post beam notch connections. Adding decking and bracing will improve the strength and structural stability of the octagon.
If you are planning on installing a gazebo on top of the octagon, make sure your footings are sized to support the extra weight of the roof and that the gazebo is properly attached to the frame.
How to Decorate Deck Support Columns
Browse some examples of decorative deck support posts for tall decks.
Reinforcing Deck Rim or Band Joists
Learn a technique to strengthen your guard rails by installing a double rim joist and adding structural blocking to reduce bounce.
How to Build a Ground Level Deck
Adding a ground level or floating deck to your home may be the perfect addition to your outdoor space. Learn how to build a ground level deck at Decks.com.
How to Install Decking Over Existing Concrete Slab, Patio, or Porch
Discover the best techniques to build a deck over concrete, ensuring proper drainage and stability, while creating a beautiful outdoor space.
How To Build a Roof Over A Deck
Extend your outdoor living space with a covered deck! Discover the key considerations like structural support, roof styles, materials, and costs.
6 Best Alternatives to Wooden Decking
While wood decking was previously considered the standard material for building a deck, that’s changed. Homeowners have been exploring and embracing different types of materials, and the availability of alternative decking materials has grown significantly.
More Helpful Resources
Explore Articles by Topic

Footings
Information related to installing frost footings for decks

Framing
Learn structural framing methods

Decking
Learn about wood and composite decking materials

Stairs
An in-depth look at the complex issue of how to build stairs

Railings
How to install guardrails and handrails to meet IRC code

Features
An overview on water drainage, benches, planters and lights

Design
The basics of deck design

Planning
Learn about permits and working with contractors

Porches & Patios
Build a covered deck to enjoy all seasons

Ledger
Proper attachment techniques

Care
Maintain your deck to maintain your investment

Materials
An overview on water drainage, benches, planters and lights
Why is Joist Protection so Important for Your Deck?
If you’ve ever seen a piece of wood left out in the weather for any period of time, you know what happens: decay. Whether through wet rot, insect damage, or mildew, the fibers begin to break down.
How to Attach Deck Post Bases to Concrete Footers
Follow our step-by-step instructions on how to install a support post to a concrete deck footing using a post base connector and anchor.
How to Use Steel Metal Deck Support Posts and Columns
Steel deck posts with base plates can be used as an alternative to wood posts for supporting your deck.
What to Consider When Building A Wrap-Around Deck
Looking to add a wrap-around deck to your home but unsure of what the process involves? Check out this guide to learn more about top considerations when building a wrap-around deck.
How to Demolish & Remove a Deck
At some point, it might become necessary to remove an old deck, due to age or condition. Learn more about what's involved in a deck demolition and removal project.
6 Best Alternatives to Wooden Decking
While wood decking was previously considered the standard material for building a deck, that’s changed. Homeowners have been exploring and embracing different types of materials, and the availability of alternative decking materials has grown significantly.
Explore Articles by Topic

Footings
Information related to installing frost footings for decks

Framing
Learn structural framing methods

Decking
Learn about wood and composite decking materials

Stairs
An in-depth look at the complex issue of how to build stairs

Railings
How to install guardrails and handrails to meet IRC code

Features
An overview on water drainage, benches, planters and lights

Design
The basics of deck design

Planning
Learn about permits and working with contractors

Porches & Patios
Build a covered deck to enjoy all seasons

Ledger
Proper attachment techniques

Care
Maintain your deck to maintain your investment

Materials
An overview on water drainage, benches, planters and lights