Stair Treads vs Stair Pans: What's the Difference & Which Do You Need?
If you've ever specified stairs for a commercial building, industrial facility, or a construction project and gotten a quote back with "treads" and "pans" listed as separate line items, you've probably paused and wondered why you'd need both. It's a fair question. The terms get used loosely on job sites, and even some suppliers mix them up.
The short version: a stair pan is the structural shell that holds a stair step in place, and a stair tread is the surface you actually walk on. They're related, but they solve different problems. Getting this distinction right before you send drawings out for fabrication can save you a redesign, a failed inspection, or a change order nobody budgeted for.
This article breaks down what each component actually does, when you need one versus the other (or both), and what to think about before you order custom stair pans or treads for a project.
What Are Stair Treads?
A stair tread is the horizontal walking surface of a single step — the part your foot actually lands on. In metal fabrication, treads are typically made from:
Checker plate (diamond plate) steel or aluminum, for slip resistance in dry or wet conditions
Perforated or grip-strut plank, common in industrial and outdoor applications where water, snow, or debris needs to pass through
Grating, used where drainage, weight reduction, or airflow matters more than a solid surface
Solid plate with applied nosing, often seen in commercial and retail settings where appearance matters as much as function
Treads can be standalone pieces that get welded or bolted directly onto a stair stringer (the diagonal support beam), or they can sit inside a stair pan as a separate wear surface that can be replaced later without touching the structure underneath.
That second point matters more than people expect. On a lot of industrial stairs, the tread takes the abuse — foot traffic, dropped tools, forklift pallets scraping by — while the pan underneath stays structurally sound for decades. Separating the two means you're not rebuilding a staircase just because the surface wore out.
What's the Difference Between Stair Treads & Stair Pans?
Here's the plain-language version:
A stair pan is the container. It's a formed steel shell, shaped like a shallow box, that gets welded between stringers to create the shape and support of each step. Pans are typically filled with concrete, grout, or another fill material once installed.
A stair tread is the surface. It's what finishes the top of the step and provides the actual walking surface, whether that's poured concrete over a pan, a separate metal plate, or a grating insert.
Think of it this way: the pan gives the stair its shape and strength before the finish goes in. The tread is the finish — the part that determines slip resistance, appearance, and day-to-day durability.
A common misconception is that stair pans and stair treads are interchangeable terms for "the metal part of the stair step." They're not. A pan without a tread finish is an incomplete step — it's structurally there but not usable as a walking surface until it's filled or fitted. A tread without a supporting pan or stringer connection has nothing to hold it in place.
Another point of confusion: some fabricators use "pan-type tread" to describe a stair pan that's been filled with concrete and finished, effectively combining both functions into one component. That's a legitimate and common configuration, but it's worth clarifying with your fabricator exactly what's being quoted, since pricing and lead times differ based on whether concrete fill, grating, or plate finish is involved.
Stair Treads vs Stair Pans: Side-by-Side Comparison
| Feature | Stair Treads | Stair Pans |
|---|---|---|
| Primary function | Walking surface | Structural shell/form for the step |
| Typical material | Checker plate, grating, grip-strut, perforated plank | Formed sheet steel (usually 10–14 gauge) |
| Installed with | Welded, bolted, or set into a pan | Welded between stringers |
| Fill required | No (tread is the finished surface) | Usually yes — concrete, grout, or left open for grating |
| Replaceable independently | Often yes, if bolted rather than welded | Rarely — replacing a pan usually means cutting into the stair structure |
| Common in | Retail, office, and public-access stairs | Industrial, commercial exit stairs, parking structures |
| Slip resistance | Determined by tread type (diamond plate, abrasive coating, grating) | Determined by whatever finish is applied on top |
| Cost driver | Material grade, finish, and coating | Steel gauge, pan depth, and quantity/complexity of bends |
| Typical lead time factor | Faster if stocked material; slower for custom perforation or coating | Depends on forming complexity and whether concrete fill is done on-site or off |
This table is a general guide, not a rulebook. Every project has its own code requirements, and local building officials may have specific requirements for tread depth, nosing, and load ratings that override general practice.
When to Use Stair Treads (Industry Applications)
Stair treads (as standalone components, separate from a filled pan) tend to show up in projects where:
1. The stair structure already exists
If you're retrofitting or replacing worn walking surfaces on an existing metal stair, you're almost always dealing with a tread replacement, not a pan replacement. This is common maintenance work in manufacturing plants, warehouses, and parking garages where the stringers and pans are structurally fine but the surface has worn smooth, rusted through, or become a slip hazard.
2. Weight matters
Grating or perforated plank treads are lighter than a concrete-filled pan. On mezzanines, catwalks, and elevated platforms where every pound of dead load affects the structural design, a tread-and-stringer combination without concrete fill is often the more practical choice.
3. Drainage or airflow is a factor
Outdoor stairs, stairs near wash-down areas, or stairs in facilities with heavy dust or fume extraction often use open grating or perforated treads so water, debris, or air can pass through rather than pool on a solid surface.
4. Appearance and finish matter
In office buildings, retail spaces, and public-facing commercial projects, treads are often selected for how they look and feel underfoot — diamond plate with a painted finish, rubber-covered nosing, or a coated grip surface — as much as for their function.
Typical industries: commercial construction, retail fit-outs, warehouse maintenance, manufacturing facility upgrades, parking structure renovations.
When to Use Stair Pans (Industry Applications)
Stair pans are the go-to when:
1. You're building new structural stairs from scratch
New exit stairs, egress stairs, and interior commercial stairs are very often built using formed steel pans that get filled with concrete on-site or in the shop. This is standard practice in commercial construction because it delivers a solid, code-compliant, fire-rated walking surface once finished.
2. Long-term durability under heavy traffic is the priority
A concrete-filled pan handles heavy, sustained foot traffic — think parking garages, industrial exit stairs, and public buildings — better than most standalone tread systems, since the concrete fill distributes load and resists wear over time.
3. Fire code or building code requires it
Many commercial exit stair specifications call for pan-type stairs with concrete fill specifically because of fire rating and structural requirements. If you're working with an architect or engineer on a new commercial stair, there's a good chance pans are already specified in the drawings, whether or not the term "stair pan" is used explicitly.
4. You need a consistent structural shape across many steps
When a project calls for dozens of identical steps (a stairwell running multiple floors, for example), pans allow for consistent, repeatable fabrication. Once the pan die or form is set, producing uniform steps at volume is far more efficient than custom-fitting individual treads one at a time.
Typical industries: commercial construction, industrial facility construction, oil and gas plant stairs, mining site infrastructure, multi-level parking structures.
Stair Treads vs Stair Pans: When You Might Need Both
In a lot of real-world projects, the answer isn't "tread or pan" — it's both, working together.
Here's a common scenario: a general contractor is building an exit stairwell for a commercial building. The stair pans are fabricated and installed between the stringers, then filled with concrete on-site. Once cured, a nosing or non-slip finish (which is technically a tread element) gets applied to the leading edge of each step for slip resistance and code compliance.
Another common combination: an industrial client has an existing set of pan-and-concrete stairs, but the concrete surface has worn down or become uneven after years of forklift and foot traffic. Rather than tearing out the pans and re-pouring concrete, they'll have a fabricator supply bolt-on metal tread covers that sit over the worn concrete, extending the life of the stair without a full structural rebuild.
A quick way to think about it:
New construction, code-driven stairs → usually pans, often finished with a tread nosing
Maintenance and retrofit work → usually standalone treads
High-traffic industrial stairs needing both strength and a durable wear surface → often both, from day one
If you're not sure which situation applies to your project, that's a conversation worth having with your fabricator before drawings are finalized — not after steel is already cut.
Custom Fabrication for Stair Treads and Pans
Off-the-shelf stair components work fine when your stair dimensions match a standard size and your application doesn't have unusual load, environmental, or code requirements. A lot of projects don't fit that description.
Common reasons custom fabrication becomes necessary:
Non-standard rise and run dimensions — older buildings, renovations, and retrofits rarely match modern stock sizing
Unusual stringer angles or curved stairs — spiral or curved staircases almost always require custom-formed pans
Specific load ratings — industrial and oil and gas facilities often specify load capacities beyond what standard stock products are rated for
Corrosive or high-moisture environments — projects in mining, oil and gas, or outdoor exposure often need specific steel grades, galvanizing, or coatings that stock products don't offer
Matching existing stairs — replacing a section of an older stair system usually means matching an obsolete pan depth or tread pattern that isn't produced anymore
A few design considerations that affect manufacturability and cost
Pan depth and gauge
Deeper pans and heavier gauge steel add material cost but also add strength and reduce the risk of oil-canning (that visual rippling you sometimes see in thin sheet metal under load or heat). If your stair sees heavy or repeated impact loading, it's worth discussing gauge before finalizing drawings — thinner material might save a bit up front but cost more in repairs down the line.
Consistent stringer spacing
Pans are formed to fit a specific stringer width. If stringer spacing varies even slightly across a run of stairs (which happens more often than people expect on older structures), it can turn a straightforward pan order into a custom-fit job for every single step, which affects both lead time and price.
Finish and coating requirements
Painted, galvanized, or powder-coated finishes each have different lead times and minimum order considerations. Galvanizing, for example, is usually done off-site at a dedicated facility, which adds shipping and scheduling into your project timeline — something to plan for early rather than discover the week before installation.
Tread pattern and slip resistance
Codes vary by jurisdiction on required slip resistance ratings, especially for public-access stairs. Confirming your local code requirement before finalizing tread material (checker plate vs. abrasive coating vs. grating) avoids a failed inspection after the stairs are already installed.
Why measurements matter more than people think
One of the most common causes of delay in custom stair pan and tread orders isn't the fabrication itself — it's inaccurate field measurements. A pan that's off by even a small margin on stringer width or step depth may not fit without on-site modification, which eats into installation time and can throw off a project schedule that other trades are relying on. Careful, verified measurements before an order is placed save far more time than they cost to take.
FAQ: Stair Treads and Stair Pans
What's the main difference between a stair tread and a stair pan?
A stair pan is the structural steel shell that gives a step its shape and gets filled with concrete or fitted with grating. A stair tread is the finished walking surface — either applied to the top of a pan or installed as a standalone piece on a stair stringer.
Can stair pans be used without concrete fill?
Yes. Some projects use pans filled with grating instead of concrete, especially in outdoor or wash-down applications where drainage matters. The pan still provides the structural shape and stringer connection; the grating serves as the tread.
Do stair treads need to match the stair pan material?
Not necessarily. It's common to see steel pans finished with an aluminum diamond plate tread, or a concrete-filled pan finished with a rubber or coated nosing. What matters more is that the combination meets your project's load and slip-resistance requirements.
How long does custom stair pan fabrication typically take?
Lead times depend on quantity, pan depth, steel gauge, and finish requirements (galvanizing or painting adds time). Straightforward orders with standard dimensions typically move faster than projects requiring custom-fit pans for irregular stringer spacing.
Are stair pans required by building code?
Many commercial building codes require specific fire ratings and structural performance for exit stairs, which often leads architects and engineers to specify concrete-filled steel pan construction. Requirements vary by jurisdiction and occupancy type, so it's worth confirming with your local building official or engineer of record.
Can worn stair treads be replaced without replacing the pans?
In most cases, yes — this is one of the practical advantages of separating the tread from the pan. If the pans and structure are still sound, a new tread surface (bolt-on plate, new nosing, or grating insert) can often be installed without touching the underlying structure.
What material is best for outdoor stair treads?
Galvanized checker plate or grip-strut plank are common choices for outdoor applications because they hold up to moisture and provide drainage. Solid plate without perforation can become a slip hazard outdoors when wet, icy, or covered in debris.
Can stair pans be fabricated to match an existing, older stair system?
Yes, though it usually requires field measurements of the existing structure since older pan depths and stringer spacing often don't match current standard sizes. This is a common request for renovation and retrofit projects.
BSG (Ball Service Group) has been fabricating structural steel, stair pans, and custom metal components out of Kitchener, Ontario since 1987, working with clients across construction, automotive, mining, and oil and gas industries. If you're planning a project that involves custom stair pans, treads, or structural steel components, reach out to our team to talk through your drawings and requirements.