What is an I-Joist and How are They Made - Did You Know?

Prefabricated wood I-joists are structural, load-carrying products used in residential
and light commercial construction. Wood I-joists are straight, lightweight, and
available in long lengths, which allows for easy installation.

I-joists are the ideal choice for designers and builders who want to provide their customers with high quality floor systems. They provide consistent performance for the most demanding residential applications.
Easy to Specify - Performance standardization allows specifiers to select and specify I-joists from various manufacturers using a single set of span tables and engineering
values. Standardization also provides for increased product availability, minimizing the need for costly substitution and re-engineering.
Simple to Install - I-joists save builders time, and therefore money. I-joists are typically pre-cut in two-foot increments of length and shipped to the jobsite ready to install. This minimizes jobsite cutting and material waste. I-joists can be cut and fastened with traditional tools and fasteners - no special tools are required. In addition; Span Ratings for uniformly loaded glued- nailed residential floors for both simple and multiple span applications are clearly stamped on each APA trade- marked I-joist, making them easier
For builders and remodelers to install properly, and more visible for code officials to inspect. Since I-joists can typically be used at greater joist spacings as compared to lumber, fewer pieces must be cut and handled on the job site, malting I-joist installation less costly and less wasteful for the builder.
Allow Design Fledbility - The availability of long lengths allows multiple span installations thus speeding construction by eliminating the need to lap joists over
bearing walls or support beams. This also means fewer pieces to handle. The availability of long lengths and relatively deep joists also gives designers the freedom to create more open spaces and reduces the need for supporting walls, columns, or beams.

Dimensionally Stable - I-joists will not warp, twist, or shrink, and are more uniform in their dimensions than sawn lumber joists. The straightness and uniformity provides a stiffer, more uniform floor with fewer squeaks,,, resulting in higher customer satisfaction.

Lightweight - Because I-joists typically weigh less than half of comparable conventional framing lumber, they can be installed quickly and efficiently. Cut on the job site to permit the passage of electrical wiring, plumbing and duct- work. This cannot always be accomplished with sawn lumber joists and such mechanical systems must be passed under the joist system. Most I-joist manufacturers also provide knockout holes along the length of the joists to facilitate the installation of electrical wiring or light plumbing line with a hammer as needed.

I-Joist Composition
The flange material for I-joists is typically dimension lumber or laminated veneer
lumber (LVL); the web is plywood or OSB. The "I" configuration provides high
bending strength and stiffness characteristics. The web resists shear stresses and the
flanges resist bending stresses.

I-joists are used extensively in residential floor and roof framing. They are ideal for long spans, including continuous spans over intermediate supports. Because I-joists are straight and true, it's easier for builders to avoid crowning and maintain a level framing surface. In addition, wood I-joists are typically stocked and readily available in depths that meet the needs of residential framing.

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