Understanding Deck Beams: A Comprehensive Guide
When discussing the structural components of a deck, you might hear the term "deck beam" thrown around. But what exactly is a deck beam, and what are some of its common names? Let's delve into the world of deck construction and explore the various terms used to describe these crucial elements.
What is a Deck Beam?
A deck beam, also known as a joist header, is a horizontal structural member that supports the joists (or floor joists) of a deck. It runs perpendicular to the joists and transfers the weight and load of the deck to the supporting posts or columns. In essence, deck beams play a vital role in distributing the weight of the deck evenly, ensuring its stability and longevity.
Common Names for Deck Beams
Deck beams go by various names, depending on the region, the specific application, or the preference of the builder. Here are some of the most common terms used to describe deck beams:

- Joist Header: As mentioned earlier, this term is often used interchangeably with deck beam. It refers to the beam that supports the joists and transfers their load to the supporting posts.
- Band Board: In some regions, particularly the southern United States, deck beams are referred to as band boards. This term is more commonly associated with porch construction but can also be used to describe deck beams.
- Beam: In its simplest form, a deck beam is often just referred to as a beam. This term is used to describe any horizontal structural member that supports weight and load.
- Header: Similar to the joist header, the term header is used to describe the beam that supports the joists and distributes their load.
- Ribbon Board: This term is less common but can be used to describe a deck beam, particularly in older construction or regional dialects.
Deck Beam Materials
Deck beams can be constructed from various materials, with the most common being pressure-treated lumber, composite materials, and steel. The choice of material depends on factors such as budget, desired lifespan, and local building codes.
Pressure-Treated Lumber
Pressure-treated lumber is the most common material used for deck beams due to its affordability and wide availability. It is treated with preservatives to resist rot, decay, and insect damage, making it a durable choice for outdoor applications.
Composite Materials
Composite deck beams are made from a combination of plastic and wood fibers, creating a low-maintenance, durable, and eco-friendly option. They are resistant to rot, decay, and insect damage, making them a popular choice for modern deck construction.

Steel
Steel deck beams are often used in commercial or large-scale residential projects due to their exceptional strength and durability. They are more expensive than lumber or composite materials but offer a longer lifespan and require minimal maintenance.
Deck Beam Sizes and Spacing
The size and spacing of deck beams depend on the size and load of the deck, as well as local building codes. Generally, deck beams range in size from 2x8 to 2x12, with larger beams used for longer spans or heavier loads. Beams are typically spaced 16 or 24 inches on center, depending on the size of the beam and the load it must support.
Installing Deck Beams
Installing deck beams involves several steps, including calculating the load, selecting the appropriate beam size and material, and properly supporting the beams with posts or columns. It's essential to follow local building codes and consult with a structural engineer if you're unsure about any aspect of the installation process.
Maintaining Deck Beams
Proper maintenance is crucial for ensuring the longevity and safety of deck beams. Regular inspections can help identify any signs of damage, such as rot, decay, or insect damage. Prompt repairs and routine cleaning can help extend the lifespan of deck beams and prevent costly replacements.
Conclusion
Deck beams, also known as joist headers, play a critical role in the structural integrity of a deck. Understanding the various terms used to describe these essential components and the factors that influence their selection and installation can help homeowners make informed decisions about their deck construction or renovation projects. Always consult with a professional or a structural engineer when planning or building a deck to ensure it is safe, stable, and compliant with local building codes.
More Details
11.04.2023 ... Beams, also called girders, are deck components that support the frame of the deck. Beams are installed alongside the rim joists (joists at the ...

29.07.2024 ... Beams. Deck beams, also known as girders, are a part of the deck substructure that supports the joists. Typically positioned parallel to the ...

The deck components that carry the load—the weight of the deck itself, furniture, and people—are called substructure parts ...

30.07.2024 ... The outside joist that runs parallel to the ledger board is called a rim or band joist. Sometimes two or more rim joists are combined to create ...

Deck beams are structural elements fitted transversely on decks, supporting longitudinal framing and designed with scantlings that depend on their span, ...

19.11.2021 ... They're horizontal beams that support your decking, made from treated lumber. The joists are held in place by ledger boards, rim joists, and ...

27.03.2025 ... Joists: The joists are supporting beams underneath a decking area. Joists will vary depending on the base material, for example, Composite ...

I call beams the “backbone” of deck framing. They support joists, which hold the deck boards and the deck's weight above. When designing your deck, ...

10.04.2026 ... Decking—also called deck boards or deck flooring—is the most visible part of your deck. It sits on top of structural components (like the joists ...

22.03.2022 ... Share your videos with friends, family, and the world.

06.07.2020 ... Hurricane Tie – Piece of structural hardware that connect joists to beams. Its purpose is to keep the joists in place. Joist Hanger – Piece of ...

Rim joists, or what are also called "band" joists, run around the perimeter of the deck. In the case where they run parallel to the other floor joists, like ...

A deck's ledgers are what anchor the deck to a house. They also serve as supports for one side of your joists. Something called a header joist must be used for ...

07.09.2021 ... A drop beam and a flush beam will cost exactly the same minus a few joist hangers needed for the flush beam. I much prefer the look of a flush beam as well.

A flush beam, also known as a header beam, is a type of beam that's installed at the same level as your joists. When using a flush beam, you must attach your ...

24.03.2023 ... 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, ...

08.03.2024 ... Not to say flush beam doesn't serve a purpose, but overall I prefer drop beams all the way. 2y · 9 likes. Mark ...

A joist is a horizontal structural member used in framing to span an open space, often between beams that subsequently transfer loads to vertical members.

28.09.2021 ... A deck beam is a longitudinal piece of lumber placed on top of the structural columns. The beams are essential for framing and substructure ...

17.12.2024 ... Joists: Horizontal framing members (usually 2x stock) fastened on top of the beam or flush with the ledger to support the decking. A header is ...
