Engineered lumber costs more per piece than sawn lumber, and in the right spots it pays that premium back with interest. I-joists earn their keep on long, flat floor spans. LVL earns it in headers, flush beams, and anywhere a built-up 2x package would be working at its limit. Everywhere else — standard walls, plates, blocking, short spans — dimensional lumber is still the right call, and we frame most of every building with it.
Where I-joists beat sawn joists
A #2 SPF 2x10 floor joist at 16 inches on center is comfortable to about 14 or 15 feet. A 2x12 buys you another foot or two. Past that, sawn lumber runs out of span, and doubling joists or dropping in extra beams starts eating money and headroom. An 11-7/8 inch I-joist at the same spacing carries 18 to 20 feet without drama, and deeper series go well beyond that.
Span is only half the story. The other half is consistency:
- Flat floors. I-joists don't crown, twist, or shrink the way sawn joists do. On a building with hard-lid ceilings below, that shows up as drywall that doesn't crack and floors that don't telegraph humps.
- Fewer callbacks. Squeaks and nail pops trace back to lumber movement more often than to framing labor. Engineered floors move less, period.
- Long lengths. I-joists come in lengths sawn lumber can't, so you can run continuous over interior bearing instead of lapping — which stiffens the floor further.
- Mechanical runs. Pre-stamped knockouts keep HVAC and plumbing from butchering the structure after we leave.
The catches
I-joists are not a straight swap. They need web stiffeners and squash blocks at point loads, the flanges can never be cut or notched, hangers and blocking are product-specific, and exposed I-joists in basements and certain commercial assemblies need membrane protection for fire performance. None of that is hard — but it has to show up on the shop drawings, and the crew has to know it. A crew that treats I-joists like 2x12s builds problems into the floor that surface a year later.
Where LVL earns its cost
LVL runs roughly three times the bending strength of #2 sawn lumber and comes dead straight. We reach for it in the same handful of places on almost every job:
- Headers over wide openings — garage doors, storefront glass, big patio walls — where a built-up 2x header sags over time.
- Flush beams in floor systems where headroom won't allow a dropped beam.
- Stair and shaft openings, where trimmers and headers carry concentrated loads.
- Stacking point loads in three- and four-story multi-family, where roof loads land on posts and beams all the way down.
- Tall walls — LVL studs stay straight past 12 feet where sawn studs bow and throw the finishes off.
An LVL header can cost two to three times the built-up 2x package it replaces. Spread across a building, that difference is small — and one sagged header over a storefront costs more to fix than every LVL on the job.
Where dimensional lumber still wins
Standard 8- to 10-foot walls, plates, blocking, backing, short joist spans, anything a framer needs to cut and fit in the field — dimensional lumber is cheaper, stocked everywhere, and forgiving. There's no reason to pay engineered pricing where a 2x6 does the job. We also like sawn lumber this time of year for anything that sits exposed: a week of fall rain doesn't hurt a lift of SPF, but OSB-webbed I-joists want a roof over them reasonably fast, and we sequence for that when we're pushing dry-in ahead of winter.
How this plays out on a real building
On a typical multi-family or commercial job we run a hybrid: dimensional lumber walls, I-joist or open-web truss floors, LVL at headers, beams, and stacking loads, and roof trusses on top. Figure the engineered floor package adds somewhere around 10 to 25 percent in material over sawn joists — and gives a chunk of that back in labor, because straight, long, light material frames faster. For where that lands in a complete framing number, see our commercial framing cost guide, or run your building through our ballpark estimator.
Have a floor plan pushing past sawn-lumber spans? Send us the plans and we'll price it both ways.