Walk up to our counter with a guard panel or a walkway to build, and one of the first questions you'll hear is: expanded or perforated? Both start life as a solid metal sheet. Both end up full of holes. But they're made in completely different ways, and that difference decides how strong the panel is, how it looks, what it costs, and which jobs it's right for.
Howard Wire Cloth has been cutting both to size in Hayward, California since 1938. Here's the plain version of how they differ and how to pick between them.
What Is Expanded Metal?
Expanded metal is made by slitting a solid sheet and stretching it in the same operation. A die cuts rows of small slits, and as the sheet is pulled, each slit opens up into a diamond-shaped opening. Nothing gets punched out and nothing hits the scrap bin. One sheet goes in, and a larger sheet full of diamonds comes out.
Because the sheet is stretched rather than cut apart, every strand stays connected at the knuckles, the joints where strands meet. There are no welds to break and no seams to open up. That one-piece construction is the whole story of expanded metal: it covers more area than the flat stock it came from while keeping most of its load-carrying ability, which gives it an excellent strength-to-weight ratio.
Standard expanded metal comes off the machine with the strands set at an angle. That angle adds rigidity and gives the surface a natural grip underfoot, which is why you see it on catwalks, ramps, and stair treads. If you want a smooth face instead, flattened expanded metal is the same product run through a cold roll after expanding. Flattening presses the strands down flat, thins the sheet slightly, and widens the openings a bit. It's the version to reach for on shelving, cages, screen doors, and anywhere a raised diamond would snag.
You can see the common styles and materials in our expanded metal collection, all cut to the size you need.
What Is Perforated Metal?
Perforated metal starts as the same solid sheet, but instead of stretching it, a punch press knocks holes clean through it in a set pattern. Round holes on staggered centers are the workhorse, but square, slotted, hexagonal, and decorative patterns are all standard fare. Take a look at our perforated metal collection for the patterns we stock.
Punching gives you something expanding can't: precise control. Hole size, spacing, and percent open area are all set by the tooling, so if your job calls for a specific hole diameter on specific centers with a specific open area, perforated is how you get exactly that, sheet after sheet. The sheet also stays dead flat with a smooth face, since no stretching or cold working is involved.
The trade-off is waste. Every hole is a slug of metal punched out and scrapped, and the mill paid for the full sheet that went into the press. The more open area you want, the more of the sheet ends up as scrap, which is a big part of why perforated usually costs more than expanded metal covering the same square footage. Punching also removes material without adding any stiffness, so strength drops as open area climbs. Expanded metal moves the other direction: the working of the metal during stretching actually helps rigidity.
Expanded vs. Perforated at a Glance
| Factor | Expanded Metal | Perforated Metal |
|---|---|---|
| How it's made | One sheet slit and stretched in a single operation | Holes punched out of a solid sheet |
| Construction | One continuous piece, no welds or joints | Solid sheet with material removed |
| Material waste | None; the sheet is stretched, not cut away | Punched slugs become scrap |
| Strength-to-weight | Excellent; angled strands add rigidity | Good, but drops as open area rises |
| Surface | Raised diamond texture, or smooth if flattened | Flat and smooth |
| Open area control | Set by the die; limited fine-tuning | Precise; hole size, centers, and open area specified exactly |
| Opening shapes | Diamond, plus hexagonal and specialty patterns | Round, square, slot, hex, decorative |
| Typical look | Industrial, utilitarian | Clean, uniform, architectural |
| Common picks | Walkways, ramps, machine guards, security, shelving | Facades, grilles, sunshades, acoustic panels, sizing and screening |
Strength, Weight, and Cost
Pound for pound, expanded metal is hard to beat. Since no material is removed, a sheet keeps its cross-section working for it, and the angled strands act a little like tiny trusses. That's why it's the default for walkway surfaces, trailer ramps, equipment guards, and security screening over windows and vents. The raised diamonds also shed mud and give boots something to bite on, which flat perforated sheet can't do.
On cost, expanded usually wins too. It's one operation with zero scrap, so you're not paying for metal that ends up on the punch-press floor. If you're covering a lot of area and the exact hole geometry doesn't matter, expanded metal stretches your budget the same way it stretches the sheet.
Perforated earns its premium when the numbers matter. If a drain cover needs to stop anything over a certain size, a speaker grille needs a certain open area for sound, or a screen needs to pass a specific airflow, punched holes give you a real specification instead of an approximation.
Looks: Industrial Grit vs. Clean Lines
This one is simple. Expanded metal looks like what it is: tough, textured, industrial. Plenty of designers use that on purpose for railing infill, furniture, and loft-style interiors, but it reads as utilitarian.
Perforated metal is the architectural pick. Uniform round holes on tight centers photograph clean, take powder coat beautifully, and can even be punched in custom patterns or graduated hole sizes for building facades, sunshades, column wraps, and signage. If the panel is the first thing a customer sees, perforated is usually the answer. Our architectural mesh guide covers these decorative applications in more depth, including woven options.
When You Need Exact Openings: Screening and Filtration
For sizing and scalping work, separating gravel, letting fines drop through a chute, protecting a pump intake, perforated metal is the pick of the two because the hole size is exact and repeatable. Expanded diamonds vary too much to size material against.
That said, punching has a practical lower limit. Once you need openings finer than a punch can make, you've left plate products behind entirely and you're into woven wire mesh, which goes down to openings measured in microns. Our filtration and sieving guide walks through where perforated ends and wire cloth takes over.
Which One Do You Need? Quick Picks
- Walkways, catwalks, ramps, stair treads: standard expanded metal. Grip plus strength-to-weight.
- Machine and equipment guards: either works; expanded is usually the economical choice. See our machine guarding guide for sizing openings around pinch points.
- Security screens, window and vent guards: expanded metal. One-piece construction means there's no joint to pry apart.
- Shelving, cages, smooth-touch surfaces: flattened expanded metal.
- Building facades, sunshades, decorative panels: perforated metal for the clean, uniform look.
- Grilles, speaker covers, acoustic and HVAC panels: perforated metal, where open area needs to hit a number.
- Sizing, screening, drainage with an exact cutoff: perforated metal; move to woven wire cloth for fine work.
Both products are commonly available in carbon steel, galvanized, stainless, and aluminum, and both are cut to the size you need in our Hayward shop. If you're not sure which alloy suits your environment, that's a two-minute phone conversation: (510) 887-8787.
Frequently Asked Questions
Is expanded metal stronger than perforated metal?
For the same weight of metal, generally yes. Expanded metal is one continuous piece with nothing removed, and the angled strands add stiffness. A perforated sheet gets weaker as more of it is punched away. That said, a heavy-gauge perforated plate with low open area can certainly out-muscle a light expanded sheet, so compare actual thickness and pattern, not just the product type.
Why is expanded metal usually cheaper than perforated?
No waste and fewer operations. Expanding stretches one sheet into a larger one with zero scrap, while perforating punches out slugs that get thrown away even though they were paid for. When you're covering large areas and don't need exact hole geometry, expanded metal is almost always the budget pick.
What is flattened expanded metal, and when should I use it?
It's standard expanded metal run through a cold-rolling mill after expanding, which presses the raised strands flat. Use it wherever the raised diamond texture would snag or wobble: shelf surfaces, animal cages, drawer bottoms, infill panels, and trim. If you need traction underfoot, stick with the standard raised product.
Can I get either one cut to a specific size?
Yes. Everything we sell is cut to size, from a single small piece for a repair to production quantities. If you're between two options, we'll send material to your door through our free sample program so you can judge strength and looks in hand.
Still weighing expanded against perforated? Request a quote with your dimensions and application, or order free mesh samples and put both materials on the workbench before you commit. And if it's faster to just talk it through, call us at (510) 887-8787. We're the shop that answers the phone.