24" Joist Spacing with WearDeck

What is the proper joist spacing for composite decking? In this blog post, we explore joist spacing and the necessary considerations before installing composite decking. We also cover joist spacing for plastic deck boards like WearDeck. Read on to find out more about joist spacing for composite and plastic decking.

What Is Joist Spacing?

Joists play a vital part in the framework of a deck or dock. As the horizontal members that run the length of the project, joists support the decking itself. Joists must supply the strength necessary to hold up the decking that rests on them. Joist spacing refers to the distance between joists and is measured in inches on center (O.C.). If you draw a line down the center of two joists and measure the distance between them as 24 inches, then the joist spacing is 24” O.C.

Joists often consist of wood or steel, because composite and plastic boards usually lack the strength needed to support the weight of decking. However, WearDeck offers plastic lumber in 2×8” and 2×10” profiles rated for use as joists. They allow for the creation of a fully synthetic deck or dock with WearDeck 2×8” or 2×10” boards as understructure and WearDeck 5/4×6” or 5/4×8” boards as decking and railing.

Why does joist spacing matter? The durability of a deck or dock relies on the strength and success of its framework- joists included. If a builder installs deck joists too far apart, the decking will sag. The decking you select impacts the necessary spacing of your joists. If you select a decking that can span further distances then you will save money on material and labor for your understructure.

How Far Apart Should My Joists Be for Composite Decking?

Most composite and plastic decking manufacturers recommend a maximum joist spacing of 16” O.C. or less. For commercial projects or decks installed at a 45-degree angle, composite and plastic decking brands typically recommend 12” O.C. WearDeck, plastic lumber reinforced with fiberglass, offers 5/4” boards that allow for spans of 24” O.C.

The distance that decking can span depends on the strength and rigidity of the material. The majority of composite and plastic deck boards satisfy the industry standard, supporting 100 lb/SqFt at 16” O.C. WearDeck plastic boards provide over two times the strength of typical composite and plastic decking, so they offer superior spans. For example, WearDeck 5/4×6” boards support 120 lb/SqFt at 24” O.C. and 266 lb/SqFt at the industry standard of 16” O.C.

The Benefits of Decking That Spans 24 Inches On Center

Decking with the ability to span 24” O.C. stands out in the composite and synthetic decking industry and offers significant benefits. Because it requires less understructure, decking that spans further distances allows you to save money on material and labor. Decking that spans 24” O.C. can be installed directly on preexisting projects with joists at that spacing. If you resurface a wood deck with joists at 24” O.C., you can directly replace the wood decking with an option like WearDeck. If you select a composite deck board that spans a maximum of 16” O.C., then you will need to purchase more material to install more joists.

Redecking That Spans 24” On Center

Innovative Deck & Dock Solutions is the only source for WearDeck 5/4 x 6" on the west coast.  We constantly see 20-30 year old decks that have joists spaced 24" and utilize WearDeck for redecking their existing deck without having to add additional joists.