The 10 Essential Components of a Deck

Lawrence Bonk
Written by Lawrence Bonk
Updated December 28, 2021
Back deck in residential house
Photo: Ruth P. Peterkin / Adobe Stock


  • Modern decks are a great way to entertain, offering an outdoor gathering space for friends and family.

  • A deck starts with a foundation, called the footings, and ends with a series of deck boards, sometimes referred to as the decking. 

  • Optional add-ons include a stairway, a railing, and a pergola, which is an overhanging structure that attaches to the deck for shade.

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If you love entertaining during the temperate months, but your yard is not exactly ready for prime time, a deck is a fantastic alternative. These outdoor structures go pretty much anywhere, increase the square footage of your home, and even increase your property value. Incidentally, they’re also a whole heck of a lot of fun and perfect for gatherings of family and friends. 

Hiring a pro to build a deck costs $4,000 to $11,000 and takes weeks to complete. Speed up the project by learning the essential anatomy of an outdoor deck. Here are 10 crucial deck parts to know before constructing a deck.

1. Decking AKA Deck Boards

This is the literal ground beneath your feet, as a deck’s boards lay on top of everything else. Contractors lay these deck boards as one of the final steps of construction. Before laying them down, decking arrives at the construction space and acclimates for a week or so before installation. Acclimation is a process by which wood beams breathe and settle to reduce the chances of cupping or buckling, particularly near the edges. When it comes to the type of decking, be sure to consider multiple options before picking deck material for your new outdoor space.

2. Footings

Concrete footings are the base of the deck and typically the very first step. Contractors pour concrete according to local building codes and your area’s frost depth. Footings hold up the post and post anchors. A deck’s footing is the absolute bottom layer, so they are pretty important from a structural perspective. Gravel and sand occasionally accompany the concrete to increase overall stability.

3. Posts and Post Anchors 

Posts are vertical boards attached to the footings via post anchors or concrete piers. These posts hold the support beams from the ground and ensure proper airflow underneath the deck, which allows access to the under-deck area for maintenance purposes. The post essentially designates how high the deck is above the surface, so talk to your pro about deck height before getting started on construction. 

4. Beams

Beams rest on top of the posts horizontally and serve two necessary functions. First of all, they frame out the overall size of the deck. Consider the beams akin to an outline of a college essay. Second, beams offer necessary structural support to every component that lays on top of them, including joists, deck boards, and other related parts. 

5. Joists and Rim Joists

The joists come next. A deck’s joists create a framework underneath and perpendicular to the deck boards but above the beams, adding structural support and helping achieve certain aesthetic flourishes. Rim joists, as the name suggests, operate as the outer rim of this framework. These rim joists are visible from the side, so they usually feature a bit more panache than the rest of the joist boards. To that end, a ledger is the rim joist that connects to the house. Obviously, a free-standing deck makes do without one. 

6. Blocking 

Blocking lumber pieces go between the joists to add extra stability and a place for deck-related structures, such as stairs and railways, to attach safely. These wooden pieces derive from the joist materials and install perpendicular to the joist itself. The blocks are uniform in length and on the smaller side. 

7. Railing

Wood deck with railings
Photo: Iriana Shiyan / Adobe Stock

Local statutes require a safety-enhancing railway structure if your deck is high enough off the ground. Even if the law does not dictate a railing, many local deck contractors push for one anyway. Why is that? Railings are highly customizable to suit the aesthetics of nearly any deck. They are also a great place for guests to congregate and serve multiple practical uses, such as giving folks a place to set a drink or tie up a dog’s leash. 

8. Balusters and Balustrade 

These are the two essential components of a deck railing. The balustrade—otherwise known as the top and bottom rails—frames the structure. On the other hand, the balusters are the vertically oriented posts spaced out throughout the railing. Both balustrade and balusters come in a wide variety of materials, colors, and designs. 

9. Stairway

Wood deck stairs
Photo: volgariver / Adobe Stock

You need some way to get up to the deck, and that’s where the stairs come in. A deck’s stairway features risers, indicating the height of each stair, a concrete foundational slab at the bottom, and tread atop each riser. If the deck’s stairway is visible from the side, contractors add a stringer, which supports the tread and increases the visual pizazz. 

10. Pergola

Walkout deck with attached pergola
Photo: Iriana Shiyan / Adobe Stock

A deck pergola provides a unique aesthetic flourish, added stability as they attach to the rest of the home, and, most importantly, an option for shade from the sun. After all, pergolas go above the deck itself and consist of vertical pillars that support an overhead open-lattice crossbeam grid. These are optional but offer some unique advantages, such as the ability to affix lighting or a speaker system. Pergolas are also highly customizable, so ask your pro about the materials available for projects such as deck enhancement.

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