Definition
An I-joist is engineered flooring with an I-shaped cross-section offering greater strength-to-weight ratio than solid lumber. I-joists accommodate plumbing and HVAC through pre-drilled holes and enable longer spans. Proper bracing and blocking are critical.
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I-joists provide greater strength-to-weight ratio than solid lumber joists, allowing longer clear spans. They reduce floor bounce and deflection compared to solid lumber. I-joists accommodate plumbing and HVAC ducts through pre-drilled web holes. Proper installation with blocking and bracing is critical. I-joists are lighter, straighter, and more uniform than solid lumber. Installation requires specific techniques to avoid web damage.
Pro Tip
I-joists provide excellent value and performance. Verify proper installation including adequate bracing to prevent floor problems.
Example
Floor framing uses 12-inch I-joists at 16-inch spacing to span 20 feet without intermediate support, supporting 40 psf floor load.