I-Beam vs H-Beam vs W-Beam: What's the Difference and Which One Do You Need?
I get this question constantly. Someone's done research, they've heard the terms, and now they want to know which one goes in their house. Fair question. Let me break it down for you the way I'd explain it standing in your living room.
The Terminology Gets Messy
"I-beam" is the generic term most people use. It just means a beam shaped like the letter I — flanges on top and bottom, web connecting them in the middle. Engineers look at an I-beam cross-section and it distributes material where it's most efficient: tension at the bottom, compression at the top, shear in the web. Smart design. Strong and efficient.
But "I-beam" is kind of like saying "truck." There are a lot of different trucks. Same thing with structural steel beams.
S-Beams (The Old School I-Beam)
S-beams are the old-style American Standard beams. Narrow flanges, sloped inner surfaces. These were common before the 1900s and early 1900s. You'll see them in old commercial buildings and bridges. For residential work today? Rarely used. Harder to connect things to because of those sloped flanges.
W-Beams (Wide Flange — This Is What You Actually Want)
W-beams — "W" for wide flange — are the workhorse of modern construction. The flanges are wider than S-beams, the surfaces are flat and parallel, which makes them MUCH easier to connect to. Stronger per pound in most applications. Available in a huge range of sizes.
When we install structural beams at Load Bearing Wall Pros, we almost always use W-beams. Our go-to for most residential spans is the W12x30 — 12-inch depth, 30 pounds per linear foot. That designation tells you exactly what you're getting. Not a guess. Not "a steel beam." Specifically engineered steel in a specific size.
"H-Beam" — Is That a Thing?
Sort of. "H-beam" is an informal term people use to describe wide-flange beams (W-beams) because when you look at the cross-section of a wide-flange beam, it looks more like an H than an I. Wider flanges, beefier appearance. Technically still a W-beam. The terms get used interchangeably and it drives structural engineers crazy... but it's close enough for casual conversation.
What Actually Determines Which Beam You Need
This is where people make the mistake of shopping for beams before they have an engineer. The beam isn't chosen by what's cheapest or what's available at the steel yard. It's chosen by calculation — span distance, load above it (one story? two? roof?), foundation type, local codes. Our in-house PE runs this calculation on every single job. That's how you know you've got the right beam, not just a beam.
LVL and Glulam
Worth mentioning — not all structural beams are steel. LVL (laminated veneer lumber) and glulam (glued laminated timber) are engineered wood beams that work great for shorter spans or when you want something that looks better exposed. LVL is our second-most-common option after W-beams. Predictable, strong, and cleaner looking if it's going to be visible in your finished space.
Bottom line: call it an I-beam, H-beam, or W-beam — what matters is the right size for your specific job, installed correctly, with engineering behind it. That's what we do. 12,000+ walls since 2015. 214.624.5200 (DFW) | 713.322.3908 (Houston) | 512.641.9555 (Austin).