Technical Guide · Surfaces
What They Are and Where They Belong
Surface is the one selection factor that affects safety (slip), cleaning and comfort — not structural capacity.
| Surface Finish | Character | Best Application | Note |
|---|---|---|---|
| Concave (dished) | Molded-in concave cells; drains water; moderate grip | General walkways, dry/wet areas | Standard molded finish |
| Convex (embossed) | Molded-in raised domes; firm footing; sheds water | Indoor walkways, platforms | Standard molded finish |
| Grit-top (sand/carborundum) | Embedded mineral aggregate on the face; highest wet COF | Splash zones, oily/wet decks, stairs | Specify where slip is a safety issue |
| Micro-mesh | Smaller bar openings (~19 mm); finer footing | Boot/traction areas, hose-down zones | Less open; slower drainage |
| Meniscus (woven/rolled edge) | Smooth rounded bar edge; comfortable underfoot | Light-duty, pedestrian aesthetic | Lowest wet grip |
| Smooth / hygienic | Polished, no grit; easy to clean | Food & beverage, cleanroom, pharma | Not for wet footing |
Finish choice does not change the load table; it changes the walking face. Grit-top is the default where wet/oily footing is possible.
The Wet-Coefficient-of-Friction Question
In splash, washdown or oily areas, the smooth concave/convex finish loses coefficient of friction (COF). Grit-top restores it.
- Dry, indoor, clean: concave or convex is fine and costs nothing.
- Wet or oily (splash zone, stairs, coastal): specify grit-top silica or carborundum aggregate.
- Food/pharma/hygienic: smooth finish for washdown — accept lower wet COF and manage spills procedurally.
Two Tips
Specify by duty, not habit
Do not default to grit-top everywhere; it adds cost and can trap dirt in hygienic areas. Match the finish to the wet/oil exposure and cleaning regime.
Verify grit retention
Embedded grit is part of the panel; verify it is bonded (not loose) on the sample. On stairs and edges, grit-top is the highest-value upgrade.
Why Wet Grip Differs
Slip resistance is measured as a coefficient of friction (COF) between a soled boot and the surface, dry and wet.
| Finish | Dry COF (indicative) | Wet COF (indicative) | Verdict |
|---|---|---|---|
| Concave / convex | 0.6-0.8 | 0.3-0.5 | Indoor dry OK |
| Grit-top | 0.7-0.9 | 0.5-0.7 | Wet/oily duty |
| Smooth hygienic | 0.5-0.7 | 0.2-0.4 | Washdown only |
Indicative COF ranges; verify against operator or code requirements for stairs and splash zones.
Five Things to Put in the Order
- State the finish: concave, convex, grit-top, micro-mesh or smooth.
- Specify grit-top on stairs, edges and splash/wet zones.
- Call out smooth/hygienic only for food/pharma washdown areas.
- Require a sample swatch before batch approval.
- Note that sawdust and oil on grit kills grip - clean at handover.
Match the Finish to the Duty
Chemical plant & splash zones
Wet, corrosive, sometimes oily. Specify grit-top: the wet COF matters more than cleanability, and chemical-resistant resin plus a C-veil is the priority. Concave/convex is acceptable only on dry indoor walkways within the plant.
Food, pharma, washdown
Hygiene and cleanability win over grip. Use a smooth or lightly textured surface so washdown liquid and detergents sheet off; accept lower wet COF and manage spills procedurally. Avoid grit that traps soil.
Stairs & edges
The highest-value grit-top upgrade. Stair treads and exposed nosings see the most slip risk; specify grit-top here even where the main deck is concave. Match nosing color for visibility.
Offshore & coastal
Salt spray and helicopter downwash keep surfaces perpetually wet. Grit-top with UV-stabilized resin; verify grit retention on the sample, because loose grit in the splash zone is a slip hazard, not a grip feature.
Aggregate Type and Bond
Not all grit-top is equal. The aggregate can be silica sand or harder carborundum; harder aggregate lasts longer under traffic but costs more. More important is the bond: grit should be embedded in the cured resin during molding, not glued on afterward. Embedded grit wears with the wearing course and stays flush; loose or post-applied grit detaches into a loose abrasive that itself becomes a slip and abrasion hazard. On the sample, rub the grit face firmly with a gloved hand - free particles should be minimal. For high-wear or oily service, specify carborundum and a denser grit loading; for general walkways, silica grit is sufficient and lower cost.
Grip Is a Specification, Not a Standard Finish
The walking face is the part the user never sees until it fails underfoot. Specify concave or convex only where the deck stays dry; grit-top where it is wet, oily, sloped or a stair; smooth only where hygiene beats slip. Ask for a sample swatch, check that grit is embedded not glued, and state the finish on the drawing. A few words in the specification prevent a whole deck being ordered in the wrong surface.
References
- Industry molded grating engineering guide (manufacturer PDF) — surface finishes and grit options. Manufacturer technical data available upon request.
- Industry pultruded grating metric design manual (manufacturer PDF) — grit-top pultruded bars. Manufacturer technical data available upon request.
- Slip-resistance / COF practice per access-platform standards (ISO 14122, OSHA 1910.23).
COF Performance by Surface
| Surface | Typical COF (dry) | Typical COF (wet) | Best Service |
|---|---|---|---|
| Grit-top | 0.6–0.8 | 0.5–0.65 | Wet, oily, marine, food washdown, ramps |
| Concave (dished) | 0.5–0.65 | 0.35–0.5 | General walkways, light contamination |
| Convex (embossed) | 0.5–0.65 | 0.35–0.5 | Indoor platforms, normal dry service |
| Micro-mesh | 0.5–0.7 | 0.4–0.55 | Boot/traction areas, hose-down zones |
| Smooth (meniscus) | 0.4–0.5 | 0.2–0.3 | Cleanrooms, food contact, dry areas |
Values are indicative and vary with finish wear and contamination; the point is the ranking — grit-top holds its bite when wet, smooth surfaces do not. Where slip is a safety issue, specify grit-top and require wet-condition COF data from the panel supplier.
Selecting the Surface for the Environment
- Washdown and marine decks — grit-top; the bonded aggregate keeps traction under water and detergent.
- Food and beverage floors — grit-top or micro-mesh for wet cleaning cycles; smooth only on dry contact surfaces.
- General process plants — concave or convex standard finishes; upgrade to grit-top at ramps, stairs and spill zones.
- Cleanrooms — smooth or meniscus where particulate control overrides slip risk and the floor stays dry.
Surface Maintenance and Wear
FRP anti-slip surfaces are moulded or bonded at manufacture — they do not need site-applied coating renewal like painted steel plate. Grit-top aggregate is bonded into the resin matrix and wears gradually; heavy traffic areas can be re-gritted or patched, but in normal service the surface outlasts the project's maintenance cycle. Cleaning with standard washdown chemicals does not strip the texture — a maintenance advantage unique to manufactured-in surfaces.
FRP anti-slip surfaces are moulded or bonded at manufacture — they do not need site-applied coating renewal like painted steel plate. Grit-top aggregate is bonded into the resin matrix and wears gradually; heavy traffic areas can be re-gritted or patched, but in normal service the surface outlasts the project's maintenance cycle. Cleaning with standard washdown chemicals does not strip the texture — a maintenance advantage unique to manufactured-in surfaces.Choose the Right Surface
Tell us the environment (wet/oil/cleanroom) — ZeAllgrate recommends the finish and supplies sample swatches.