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.
Joist Tape: What Is It and Do I Need It?
Dive into the benefits of joist tape and why you need it for your deck build.
Building Above Ground Pool Decks
Add that finishing touch to your above-ground pool with a customized pool deck. Learn the essential steps from planning and permitting to installation and maintenance. Discover tips on choosing materials, ensuring safety, and deciding between DIY and professional help for a seamless and stylish poolside experience.
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.
Introduction to Decking
Spacing between deck boards provides several critical functions, such as drainage & drying. Learn how to space and stagger deck boards at Decks.com.
How to Install Composite Decking
Learn about how to install composite decking. Topics include expansion and contraction issues and hidden fastener systems.
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.
Using Shims to Level the Deck Surface
Install shims or notch joist bottom across uneven joists to level your deck surface.
How to Brace a Swaying Deck
Learn how to install a diagonal brace on your deck frame to prevent racking. Check out our detailed image.
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.
Deck Replacement & Repair Costs
Not sure whether to fix your old deck or tear it down? This guide explores the costs and pros and cons of repairing vs replacing your deck.
Best Hidden Deck Fasteners
Hidden fasteners create a clean deck surface and can be used with composite, wood and other materials. Learn about hidden deck fasteners at Decks.com.
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