A Hinged Road / Yard Gully Grid & Frame (D400) is a heavy-duty drainage grate designed to sit at ground level directly over a street gully or yard catch-pit. It allows surface water and rainwater runoff to drain off paved surfaces while preventing large debris from entering the underground drainage network.

Primary Uses & Key Features

• Roadside & Industrial Surface Drainage: Installed along highway kerbsides, major carriageways, industrial yards, commercial car parks, and bus stations to quickly clear heavy rainfall and prevent surface flooding.

• Heavy Traffic Resistance (D400 Rated): Built to withstand a 40-tonne test load (400kN), making it safe for continuous heavy vehicular traffic, including HGVs, buses, and commercial lorries.

• Hinged Design for Maintenance: The grate is captive-hinged to the frame, allowing drainage workers to easily open it for gully clearance and jetting without having to manually lift off a heavy, detached iron grate.

• Anti-Theft & Safety: The captive hinge acts as a security deterrent against metal theft and prevents the grate from becoming dislodged or flipped into the road by fast-moving traffic.

Available for collection from our Rugby branch or local delivery using our own fleet.

Delivery is kerbside and the final offloading position is always subject to safe access and the driver’s discretion.

Please tell us before delivery about:

• Narrow roads or restricted entrances
• Parked vehicles or limited turning space
• Overhead cables, trees or other obstructions
• Soft, sloping or unsuitable ground
• Any other access concerns

Enter your postcode on the product page to check your delivery area. We’ll confirm the delivery date after your order is placed.

Why should a gully grate hinge in the direction of traffic flow?

Hinges should face oncoming traffic so that if a heavy vehicle's tyre strikes an unlatched or loose grate, the force pushes the hinge closed rather than flipping the iron grate open into the windscreen or path of the vehicle.

What is a gully "waterway area"?

The waterway area (measured in cm²) is the total open slot space available for water intake. D400 grates require high waterway capacities (often over 1,000 cm²) to ensure rapid storm drainage off high-speed roads and prevent aquaplaning.

Can a D400 gully grate be retrofitted into an existing frame?

No, grates and frames are manufactured as precision-matched sets to ensure non-rocking alignment and exact hinge pin fitments. Replacing just the grate into an old or different brand's frame can cause dangerous rattling, improper locking, or structural failure under load.

What is the standard installation depth for a gully frame mortar bed?

Gully frames should be bedded on a 10mm to 15mm layer of high-strength, quick-setting polyester or polymer-modified bedding mortar. This ensures the frame sits completely level with the asphalt surface and can absorb high impact loads without sinking.