A trench cover is part of an access and containment system, not simply a panel over an opening. Open mesh, structural solid top and supported plate each manage drainage, ventilation, traffic, dropped objects and lifting differently.
In brief
- Open mesh supports drainage and ventilation but allows small objects and liquids through.
- Solid-top grating combines a closed surface with a structural grating base.
- GRP plate usually needs continuous or closely spaced support unless verified otherwise.
- Load class, clear span, bearing, deflection and removal method must be confirmed for the exact installation.
Compare the three routes
| Requirement | Open mesh | Solid top | Plate |
|---|---|---|---|
| Drainage | Direct through-flow | Falls or edge drainage | Falls or sealed drainage detail |
| Ventilation | High open area | Limited | Limited |
| Small wheels | Opening must suit wheels | More continuous route | Continuous surface if supported |
| Structural span | Product load table | Product load table | Do not assume grating behaviour |
| Lifting | Panel weight and grip | Heavier panel to plan | Size, stiffness and handles |
Specification checklist
- Measure clear opening, bearing and frame tolerances.
- Define pedestrian, wheel, point and accidental loads.
- Confirm drainage, ventilation and containment needs.
- Set slip, resin, fire and environmental requirements.
- Plan panel joints, restraints, lifting points and safe removal.
- Check the receiving frame and lockable access where required.
Heavy-duty or highway applications require project-led loading and certification. Do not infer a traffic rating from material or thickness alone. Browse solid-top GRP grating and our wider grating range.
Frequently asked questions
Can GRP trench covers take vehicle loads?
Only where the complete cover and frame have verified capacity for the specified wheel and axle loading.
Can solid-top grating contain liquids?
A closed surface limits direct passage, but joints, edges, fixings and drainage still need designed containment.
Should removable covers be clipped down?
Restraint depends on uplift, traffic, security and access needs. Use an approved detail that still permits safe removal.
Match the cover and frame to the actual opening
Send dimensions, support details, traffic and drainage requirements to GRP Express for the correct product route.