I-Joists

A High-Performance Advantage


I-joistI-Joist Basics

I-joists are strong, lightweight, "I" shaped engineered wood structural members that meet demanding performance standards. I-joists are comprised of top and bottom flanges, which resist bending, united with webs, which provide outstanding shear resistance. The flange material is typically laminated veneer lumber (LVL) or solid sawn lumber, and the web is made with plywood or OSB. The robust combination of structural characteristics results in a versatile, economical framing member that is easy to install in residential and light commercial projects.


I-joist floor joistCommon I-Joist Applications

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.


Common Depths

9-1/2", 11-7/8", 14", 16". Flange widths vary from 1-1/2" to 3-1/2"; long lengths are readily available.


Common Uses

I-joists are popular for floor and roof framing.


APA PRI-400

APA Performance Rated I-joists (PRIs) are manufactured in accordance with PRI-400, Performance Standard for APA EWS I-joists, Form X720. This Performance Standard provides an easy-to-use table of allowable spans for applications in residential floor construction, allowing designers and builders to select and use I-joists from various member manufactureres using just one set of span tables. APA PRIs are recognized through ICC-ES ESR-1405.


The APA Mark of Quality

APA trademarks appear only on products manufactured by APA member mills. The mark signifies that product quality is subject to verification through APA audit—a procedure designed to assure manufacture in conformance with APA performance standards or the standard shown in the mark.


I-Joist Publications

 
Z725APA Performance Rated I-Joists, Form Z725

Includes information on Span Ratings, installation details, cantilever designs, architectural specifications and engineering design properties for APA Performance Rated I-Joists.


Access a complete list of APA publications about I-joists in APA's Resource Library.