The short answer
In modern U.S. construction, the term H-beam almost always refers to a W-shape (wide-flange) beam. A true I-beam is an older S-shape with narrow, tapered flanges. W-shapes carry more load, are easier to bolt and weld, and dominate today's structural jobs. S-shape I-beams still show up in older buildings, monorails, and specialty applications.
Side-by-side comparison
| Attribute | I-Beam (S-shape) | H-Beam / W-Beam (W-shape) |
|---|---|---|
| Flange shape | Narrow, tapered (sloped inner face) | Wide, parallel (flat inner face) |
| Cross-section | Taller than wide | Flange width often ≈ depth |
| Load capacity | Moderate — good for medium spans | High — long spans and heavy columns |
| Weight per foot | Lighter for a given depth | Heavier, but far more efficient |
| Connections | Tapered flange complicates bolting | Flat flanges — easy to bolt and weld |
| Typical use | Monorails, older structures, trolleys | Columns, beams, girders, framing |
| Designation example | S12×31.8 | W12×40 |
I-Beam (S-shape)
The classic "I-beam" — technically an S-shape — has a distinctive tapered flange that slopes from the web outward. It's the profile most people picture when they hear "steel beam," but it's now a specialty item. Because the inner flange face is sloped, bolted connections need tapered washers, which slows down fabrication. S-shapes are still spec'd for monorail beams, trolley rails, and retrofit work in older buildings.
H-Beam / W-Beam (W-shape)
The W-shape — often called an H-beam because its cross-section looks like a capital H — is the workhorse of modern structural steel. Wide, parallel flanges give it much greater resistance to bending and buckling, and the flat inner face makes bolted and welded connections straightforward. W-shapes are used for everything from ground-floor columns in a warehouse to long-span roof girders in a school gymnasium.
Which one belongs on your Midwest project?
- Ag & equipment buildings: W-shape columns and beams — long clear spans, simple bolted connections.
- Commercial & municipal: W-shape framing for floors, roofs, and mezzanines; W-shape columns for gravity and lateral loads.
- Bridges & culverts: W-shape girders paired with plate steel and rebar — see our culvert and rebar lines.
- Monorails & hoist runways: S-shape I-beams — the tapered flange is designed for wheeled trolleys.
- Renovation of pre-1960s buildings: Match existing S-shapes when tying new framing into old, or transition with a W-shape and a bolted splice.
How to read a beam call-out
A designation like W12×40 means a W-shape, nominally 12 inches deep, weighing 40 pounds per linear foot. S12×31.8 is a 12-inch S-shape at 31.8 lb/ft. The depth and weight together tell you the load capacity — your engineer's drawings will call out the exact size, and our estimators can source or fabricate to spec.
Common questions
Is a W-beam the same as an H-beam?
Yes — in U.S. steel construction, the wide-flange W-shape is what most contractors, architects, and suppliers mean when they say "H-beam."
Which is stronger?
W-shapes (H-beams) carry substantially more load than S-shapes (I-beams) of the same depth, thanks to wider flanges and a thicker web.
Can I substitute an H-beam for an I-beam?
Only with engineer approval. The two profiles have different section properties, connection details, and clearances. On monorails and trolley beams the substitution is usually not possible without redesign.
Send us your drawings — our estimators will price beams, columns, and connections.