19 Parts of a Deck: Diagram and Terminology

Whether you’re building or making repairs, our basic deck construction diagram labels and defines all parts of a deck.

Most important deck parts

There are many components of a deck – even the framing contains several pieces that come together for structural support. Here’s a look at the anatomy of a deck and how these parts work together.

Components of A Deck

A concrete footer is the foundation for your deck, providing a stable surface for deck posts. While there are different kinds of footers, most decking requires digging a hole and pouring concrete inside on top of solid soil. 

2. Post Anchor

A post anchor is a thin piece of sheet metal that allows you to connect your deck posts to your concrete footings.

3. Post

Deck posts are vertical pieces of lumber that attach to your concrete footings via post anchors. Posts provide a surface to secure your deck framing and help bear the structural weight. You can cut your deck posts below the deck surface or allow them to protrude and attach a railing to them.

4. Ledger

A deck ledger is a board that attaches to the house. It’s part of a deck framing that provides a surface to hang your joists to and secures the deck to the existing structure.

5. Flashing

Deck flashing is a thin sheet of material such as stainless steel, copper, or vinyl that goes between the house and ledger board. Deck flashing prevents moisture from entering the home and protects the home’s wall from rot.

6. Beam

Deck beams, also known as girders, are a part of the deck framing that supports the joists. Deck beams consist of treated lumber, often doubled-up, that run perpendicular to deck joists. Depending on the deck size, you may only need one beam on the exterior. For a large deck, you may need an additional beam in the middle of the framing.

7. Rim Joist

A rim joist is a piece of treated lumber that makes up the framing on the sides of the deck. Interior joists attach to them.

8. Joist

Deck joists are the boards inside the deck framing, spaced 12 to 16 inches apart, that create the structure for decking. Most joists run perpendicular to a house.

9. Joist Hanger

A joist hanger is a piece of hardware that connects joists to the outer framing. They provide structural support.

10. Bridging

Deck bridging, also known as blocking, is small pieces of lumber installed between deck joists or around the perimeter of rim joists. The purpose of deck bridging includes increased structural strength for railing, intricate decking patterns, and preventing lumber from warping.

11. Decking

Decking is the material that goes over your deck frame and joists. It’s what you walk on and see when you look at a finished deck. The most common decking materials include wood, composite, and PVC decking.

12. Hardware

Decking hardware refers to the pieces you use to attach boards. Hardware includes deck screws, joist hangers, and other fasteners.

13. Rail Post

A deck rail post provides a structure to secure the top rail and balusters. These posts are often 4 x 4, attached on the inner side of rim joists.

14. Baluster

A deck baluster is a small vertical piece that runs from your top rail to your bottom rail. Some people refer to balusters as pickets, spindles, or railings.

15. Top Rail

A top rail is the highest piece of horizontal railing that attaches to your rail posts. It gives you a foundation to secure your balusters.

16. Cap Rail

A cap rail, or railing cap, is a piece of decking material that goes over your top rail, giving it a finished look.

17. Stringer

A deck stringer is a frame for your deck stairs. It’s a board that spans from the top of the deck to the ground at an angle, providing a place for stair treads.

18. Tread

Deck treads attach flat to the deck stringer. They are the horizontal pieces on stairs.

19. Riser

Deck risers are the boards installed beneath the treads that cover the vertical area on stairs.