In short: FRP grating needs little maintenance, but not none. Inspect it at least once a year, more often in harsh service. Clean with mild detergent and soft brushes. Follow your supplier's pressure-washing limit, which can be very different between makers. Seal every new cut edge with resin. Treat UV chalking by light sanding and resealing or topcoating.
One reason buyers choose FRP grating is that it does not need painting like steel. Sun, abrasion, chemicals, impacts and loose fixings all affect it. A short yearly routine keeps it safe and extends its life. This guide draws on published maintenance manuals from grating makers.
How often to inspect
Inspect FRP structures at least once a year, as an Australian FRP structures supplier's maintenance checklist recommends. Inspect more often where the grating sees heavy traffic, chemical splash, high temperature, strong sun or vehicle loads, and after any incident such as a dropped load or fire.
What to look for
- Surface: chalking, fiber bloom (glass fibers showing), worn grit on anti-slip surfaces.
- Damage: cracks, impact marks, broken or crushed bars.
- Edges: unsealed cuts, delamination at cut-outs.
- Deflection: visible sag or bounce under normal use, which may mean overload or damage.
- Fixings: loose or missing clips; see FRP grating clips.
- Supports: corrosion of the steel beneath the grating, which FRP does not protect.
Cleaning
For routine cleaning, use water with a mild detergent and soft or medium brushes, then rinse. Avoid solvents and strong chemicals unless the resin is rated for them. Oil and grease can be removed with a suitable degreaser; check its chemical compatibility with the resin first.
Pressure washing
Limits differ widely between makers and products. The same supplier advises pressure washing pultruded FRP at no more than 50 psi. A US FRP grating manufacturer's maintenance manual allows up to 2,000 psi with the nozzle at least 12 in from the surface. Use your own supplier's figure, in writing, before cleaning at pressure. Too much pressure close to the surface can erode resin and expose fibers.
Key parameters at a glance
| Item | Guidance | Source |
|---|---|---|
| Inspection interval | At least once a year; more in harsh service | Australian FRP structures supplier |
| Routine cleaning | Mild detergent, soft brushes, rinse | Australian FRP structures supplier; US FRP grating manufacturer |
| Pressure washing, pultruded | Up to 50 psi | Australian FRP structures supplier |
| Pressure washing, one US maker's products | Up to 2,000 psi at 12 in or more | US FRP grating manufacturer |
| UV chalking | Sand lightly, then reseal or topcoat | US pultruder |
| Cut edges | Seal with compatible resin | US FRP grating manufacturer; US pultruder |
Repairing UV damage
Outdoor FRP slowly chalks and may show fiber bloom as UV light breaks down the surface resin. The same pultruder's repair manual describes the fix: clean and lightly sand the surface, then apply a resin sealer or a UV-resistant topcoat. Doing this before fibers are exposed is easier and keeps grit and appearance in good order. See UV degradation of FRP.
Sealing cut edges
Any time grating is cut on site, for example for a new pipe penetration, seal the cut edges with a compatible resin. Unsealed cuts let liquids wick into the laminate. See FRP grating installation guide and cut-out dimensions.
Repair or replace?
Small surface damage can be repaired with resin and, where needed, glass mat, following the maker's repair manual. Replace panels with cracked or broken bearing bars, deep burns, or permanent sag. Keep a few spare panels and clips for critical areas; order them with the same resin, mesh, depth and surface as the original.
Special cases
Chemical splash areas
Where acids, alkalis or solvents splash onto the grating, rinse spills promptly with water. Check that the resin is rated for the chemical; if the process has changed since the grating was bought, review the resin choice against the FRP chemical resistance guide.
Anti-slip grit surfaces
Gritted surfaces wear in heavy traffic. When grit is worn smooth, slip resistance falls. Some makers offer grit re-coating; otherwise replace the worst panels in walking routes first. For surface types, see FRP grating surface options.
After a fire or heat exposure
FRP softens and chars at high temperature. After any fire or heat exposure, keep people off affected panels until they have been inspected; replace charred or blistered panels.
Keep a record
Log each inspection with date, location, photos and actions. Records show trends, support warranty claims and help plan replacements.
When you need replacement panels, clips or a full re-deck, send the original panel data (resin, mesh, depth, surface, color) and a sketch.
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FAQ
How often should FRP grating be inspected?
At least once a year, and more often in heavy traffic, chemical splash, strong sun or after any incident.
Can I pressure wash FRP grating?
Yes, within your supplier's limit. Published limits range from 50 psi (an Australian FRP structures supplier, pultruded) to 2,000 psi at 12 in or more (a US FRP grating manufacturer).
What is the white chalky surface on old FRP?
UV chalking. Clean, sand lightly, then reseal or topcoat to restore it.
Do I need to seal cut edges?
Yes. Seal every site cut with a compatible resin to stop liquids wicking into the laminate.
When should a panel be replaced?
When bearing bars are cracked or broken, the panel is burned, or it sags permanently.
Related guides
Sources
- An Australian FRP structures supplier, FRP inspection, maintenance and repair checklist
- A US FRP grating manufacturer, Maintenance and Repair Manual
- A US pultruder, Fabrication and Repair Manual (2024)