Engineered wood I-joists (TJIs) and dimensional lumber joists solve the same problem — spanning a floor — but the tradeoffs aren't always obvious from a spec sheet.
Span capability
TJIs generally span farther without a mid-span beam than dimensional lumber of comparable depth, which can eliminate a beam and its columns entirely — a real cost and schedule win on open-concept floor plans.
Consistency
Engineered lumber doesn't crown, twist, or shrink the way dimensional lumber can, which reduces squeaky-floor callbacks and simplifies subfloor installation.
Cost and lead time
TJIs typically cost more per piece and, depending on your supplier relationship, may have a longer lead time than a dimensional lumber pack a yard has in stock — worth factoring into a bid's timeline, not just its material cost.
Labor
TJIs require blocking, web stiffeners at bearing points, and specific hanger hardware — different (and sometimes more time-consuming) than a straightforward dimensional lumber install, even though the material itself often installs faster once crews are trained on it.
The bottom line
Neither option is universally "better" — the right call depends on span requirements, budget, and what your framing crew already knows well.