I-joists are engineered wood structural members that can be used in residential and light commercial construction in place of dimensional lumber joists, such as 2x10s and 2x12s. They’re named “I-joists” because the cross-section forms an uppercase "I," similar to a traditional steel I-beam.

Follow these tips for handling and installing I-joists, in addition to those required by building codes and any provided by the I-joist manufacturer. Failure to do so can result in serious accidents or I-joist failure.

1. Store, stack, and handle I-joists vertically and level.
2. Protect I-joists from contact with the elements and dirt. Don’t store I-joists in direct contact with the ground. Protect I-joists from the weather, and don’t open bundles until it’s time for installation.
3. Brace and nail each I-joist as it is installed, using properly sized joist hangers, blocking panels, rim board, and/or cross-bridging at joist ends. I-Joists aren’t stable until completely installed, and won’t carry any load until fully braced and sheathed.
4. For cantilevered I-joists, brace top and bottom flanges, and brace ends with closure panels, rim board, or cross-bridging.
5. When the home is complete, the floor sheathing provides lateral support for the top flanges of the I-joists. Until sheathing is installed, however, temporary bracing (struts) or temporary sheathing must be installed to prevent I-joists from rolling over or buckling.
6. When I-joists are applied continuously over interior supports and a load-bearing wall is planned at that location, blocking is required at the interior support. These “squash blocks” should be slightly larger than the depth of the joists in order to carry the full load. Fasten the blocks to the top and bottom flanges.
7. Install wood blocks on both sides of an I-joist at the bearing points. These “web stiffeners” will reinforce the center web and prevent it from buckling.
8. Except for cutting to length, I-joist flanges should never be cut, notched, or drilled. The bending stress created from a cut, notch, etc. would likely cause the I-joist to fail.
9. Holes may be drilled through the center web within certain limits established by the I-joist manufacturer. In general, holes up to 1 ½” in diameter can be cut anywhere in the web. Follow the manufacturer’s guidelines for information on the distances required between holes, the distance between the flanges, minimum distances between the final hole and the bearing point, and other important specifications.
10. Never attempt to repair or install a damaged I-joist.

To learn more about the benefits of I-joists, read a related article, "I-Joists," in our Greener Building section. More Best Practices® for ensuring a quality framing job and a safer jobsite can be found in the following online training courses from BuildIQ® University:

• Framing: Floors
• Framing: Walls
• Framing: Roofs
• Jobsite Safety I
• Jobsite Safety II