What is framed trench grating?
Framed trench grating pairs a grating cover with a surrounding steel frame. The frame is set into the slab or channel first; the cover then seats into it. This is the standard way to get a durable, level, load-bearing edge around a trench opening.
What the frame does
- Carries load: transfers traffic load from the cover into the surrounding concrete.
- Provides seating: gives the cover a defined bearing surface.
- Sets the level: establishes a true finished surface for the cover to sit in.
- Protects the edge: stops the slab edge spalling under repeated loading.
Common frame forms
| Frame type | Form | Typical use |
|---|---|---|
| Angle-iron frame | Equal or unequal angle welded into a rectangle | General trench and pit openings |
| Flat-bar frame | Flat steel set on edge | Lighter duty, shallow openings |
| Integrated frame | Frame welded to the cover as one assembly | Hinged and lockable covers |
| Channel-body frame | Matched to a proprietary channel | Linear drainage systems |
Clearance, seating and noise
- The cover-to-frame gap must be small enough to stop rattling under traffic.
- Allow for coating thickness on galvanized work—the fit changes after galvanizing.
- Seating should be continuous, not point contact at a few spots.
- Lifting handles or key holes make removal practical without prising the cover.
Level and drainage relationship
- The frame top should finish at the surrounding floor level.
- A proud frame is a trip edge; a sunken frame collects water and debris.
- On graded surfaces, set the frame to follow the fall of the paving.
- Confirm the frame is anchored before the surrounding slab is finished.
Usage cautions
- Do not load the cover before the frame is fully anchored and grouted.
- Keep the seating surface clean; debris stops the cover seating fully.
- Re-check fit after galvanizing and after any field modification.
- Confirm the frame section is adequate for the specified load case.
Ordering information
- Opening width, length and slab detail
- Frame section, material and anchoring method
- Cover specification: bars, pitch, surface, finish
- Load case and finished level
- Hinge, lock or lifting requirements and quantity
Framed Trench Grating FAQ
Why use a frame at all?
It carries load into the slab, seats the cover and protects the concrete edge.
Does galvanizing change the fit?
Yes. Allow for coating thickness so the cover still seats after galvanizing.
Can the frame be hinged to the cover?
Yes, as an integrated hinged assembly for frequent access.
