What is the primary advantage of using engineered wood I-joists over traditional solid lumber joists for a long floor span?

Question: What is the primary advantage of using engineered wood I-joists over traditional solid lumber joists for a long floor span?

Answer options:

• I-joists are always less expensive per linear metre. ✅ I-joists are lighter, stronger, and more dimensionally stable.
• I-joists can be cut and notched anywhere without pre-engineering.
• I-joists provide superior sound dampening compared to solid lumber.

Correct answer: I-joists are lighter, stronger, and more dimensionally stable.

Explanation: Engineered wood I-joists are designed to be lighter, stronger, and more dimensionally stable than solid lumber joists of comparable depth, especially over long spans. They are less prone to shrinking, crowning, or warping. Their cost varies, and cutting or notching requires careful engineering. While they can contribute to a quieter floor, they do not inherently provide superior sound dampening without additional measures.