IN STOCK Slotted Drainage Version (Split Type with Open Slots)

Recessed Manhole Cover – Slotted Drainage Version (Split Type with Open Slots)

Product Introduction

The Recessed Manhole Cover – Slotted Drainage Version is a split-type invisible access cover designed for areas requiring both concealed surface aesthetics and efficient water drainage. Unlike solid infill versions, this cover features precision-engineered open slots or perforations across the lid surface, allowing stormwater, washdown water, or surface runoff to pass directly into a collection channel or sump below.

The system retains the two-piece split design: a heavy-duty support frame (stainless steel, galvanised steel, or aluminium) is permanently set into the ground, while the recessed lid – with a shallow tray (30–50mm deep) containing open slots – can be lifted out for maintenance. The lid may be left uninfilled (exposed metal slots) or partially filled with resin-bound gravel for a semi-invisible finish. This product is ideal for drainage channels, plaza edges, pool surrounds, and commercial kitchens where standing water must be eliminated without exposing unsightly grates.

Typical Applications

Landscaped drainage swales and stormwater collection points
Swimming pool perimeter drains and splash decks
Commercial kitchen and food processing plant floor drains
Airport tarmac edge drains and service pit runoff collection
Pedestrian plazas with hidden linear drainage
Car park entry/exit washdown areas and tyre-wash pits
Cold storage and industrial washdown zones (slotted for rapid drainage)

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Integrated Drainage

Optimised Slot Geometry

Split-Type Cleanout

Product Specifications

Item	Description
Product Type	Recessed manhole cover – split two-piece design with slotted or perforated lid (open drainage version)
Frame Material	Stainless steel 304 / 316 (2.0–4.0mm thick), hot-dip galvanised mild steel (3.0–5.0mm, ≥85µm), or aluminium 6061 (for non-corrosive environments)
Lid Material	Same as frame material – lid rim with recessed tray machined with drainage openings
Drainage Pattern	Longitudinal slots (5×50mm or 8×80mm at 15–20mm centres), circular perforations (Ø6–10mm staggered), or custom laser-cut geometric patterns
Open Area Ratio	25% – 50% of lid surface (customisable)
Recess Depth	30mm (minimum for gravel or no infill), 50mm (for resin-bound aggregate infill between slots)
Clear Opening	300×300mm, 450×450mm, 600×600mm, 800×800mm, 900×600mm, 1000×1000mm, 1000×500mm (linear drain use) – rectangular or square
Frame Outer Size	Clear opening + 100–150mm frame width
Load Rating (EN124)	A15 (15kN – pedestrian only) B125 (125kN – footway, car parks) C250 (250kN – kerbside, light traffic) D400 (400kN) available in heavy-section stainless or galvanised steel with reinforced slot ribs
Slot Width	5mm, 6mm, 8mm, 10mm, 12mm (narrower slots prevent high heels or rod entry)
Slot Length	40mm, 60mm, 80mm, or continuous full-length slots (recommended for linear drainage)
Lifting System	Two concealed penta-key holes (lid only) – slots do not interfere with lifting; frame has fixed lifting eyes during installation
Hinge Option	Optional heavy-duty stainless steel hinge for hinged lid (split type normally free-liftable)
Debris Control	Optional removable debris basket or sediment trap suspended below lid
Surface Finish	Mill finish (standard), brushed (stainless), hot-dip galvanised (steel), or anodised (aluminium) – no infill required but may be partially filled
Frame Features	Anchor lugs (min 4 per side), pre-punched bolt holes, optional rubber seal for odour/insect prevention in sanitary drainage
Corrosion Protection	Passivated (SS304/316), HDG ≥85µm (steel), anodised (aluminium)
Design Life	Stainless steel 316: 50+ years in coastal or chemical environments Galvanised steel (≥85µm): 20–35 years (inland) Aluminium: 40+ years (fresh water only)

Key Features & Benefits

Integrated Drainage + Invisibility

Allows surface water to disappear into the cover while maintaining a nearly flush finish. When partially filled with matching resin-bound gravel, the cover blends into paved areas but continues to drain freely.

Optimised Slot Geometry

Laser-cut or stamped slots are sized to prevent heel entrapment (≤8mm for pedestrian zones) while allowing high flow rates. Horizontal ribs between slots maintain structural integrity under wheel loads – no bending or slot deformation even at D400 rating.

Split-type Cleanout Access

For maintenance, the entire slotted lid lifts out without tools, exposing the drainage channel or sump below. Debris can be flushed or vacuumed from above; optional sediment baskets simplify cleaning.

Heavy-duty Load Performance

Reinforced slot bridges and a deep peripheral flange distribute point loads. Proof-tested to 2× rated load. Slotted lids up to C250 can be specified for car parks; D400 rated slotted covers are available for delivery yards.

Corrosion Resistance for Wet Environments

SS316 frame and lid are standard for pool surrounds, coastal plazas, and food plants. Hot-dip galvanised steel (≥85µm) offers 20–35 years in urban drainage applications. Aluminium is suitable for indoor or freshwater settings (avoid chlorides).

Anti-vandal & Anti-blockage

Slots can be designed with a “V” or trapezoidal profile to resist jamming by gravel or cigarettes. For high-debris areas, a removable coarse screen can be clipped under the lid.

Custom Patterns without Mould Costs

Using laser or waterjet cutting, any slot shape, logo slot pattern, or site-specific drainage array can be produced in low volume. Ideal for architecturally visible drainage or heritage sites requiring bespoke gratings.

One-Stop Customisation

Every parameter is fully customisable: frame material & thickness, clear opening dimensions (including non-standard rectangles), slot width/length/pattern, open area ratio, load rating (A15 to D400), lifting key type, and debris management accessories.
We offer complete design-to-delivery service – from CAD drawing and hydraulic area calculation (m²/s drainage capacity) to sample cutting and load testing.
Whether you need 10 units for a luxury hotel pool deck or 500 units for an airport apron drainage retrofit, we deliver slotted recessed covers that drain fast, stay hidden, and last decades.

Downloads

Brochures, CAD drawings, and installation guides will be available for download soon.

Material Standards

Material testing standards and certifications will be updated soon.

Fabrication & Application Standards

Fabrication and application testing standards will be updated soon.

Manufacturer’s Certification

Manufacturer certification details will be updated soon.

Calculators

Cover sizing, load rating, and material calculators will be available soon.

Frequently Asked Questions

Product-specific FAQs will be added soon. Please check our main FAQ page for general inquiries.

CUSTOMER TESTIMONIALS

Hot-dip galvanized steel grating is easy to install, gratings are strong, slip-resistant, and rust-proof. The product is strong and well-made. They have their own factory with 20 years+, Had sent me photos during shipping. Very satisfied! Will definitely order from them again.

David Wilson

Botany Street, Marrickville, New South Wales

Absolutely love this fence! The material is thick, galvanized well and anti-rust. Super easy to assemble, strong and stable for outdoor use. The team is very responsive and helpful throughout the whole order. 100% satisfied and will be a long-term buyer.

Chloe Anderson

Oak Street, Los Angeles

Bulk order of mesh finished perfectly. Uniform size and high hardness, suitable for construction and fencing projects.

Khalifa Salem

Sharjah, Industrial Area 5, United Arab Emirates

These invisible decorative manhole covers are beyond my expectations. Fine welding, smooth edges and premium material. It can be fully covered with tiles to achieve a completely invisible effect, greatly improving the overall aesthetics of the project. The supplier is responsive and reliable, will definitely reorder.

Olivia Smith

Ballarat Road, Deer Park, Victoria

The chain link fence we ordered is absolutely fantastic in every detail. The galvanized coating is even and thick, providing great anti-rust and weather resistance for long outdoor service. The mesh structure is tight and uniform, very tough and not easy to deform. The whole cooperation experience was wonderful, the supplier replied quickly and arranged everything professionally. Highly recommended for all fencing projects.

Chris Mitchell

Smith Street, Darwin, Northern Territory

Perfect fit and excellent quality. This security door hinge is solid, durable and beautifully finished. It greatly improves door stability and safety. Smooth communication and fast delivery. Very happy with my purchase.

Watanabe Shun

Taito City, Tokyo, Japan

The temporary fence is made of high-quality metal material with solid overall structure. The welding work is neat and firm, not easy to bend or damage. Hot galvanized surface provides great rust and corrosion resistance, perfect for outdoor construction sites, events and public isolation. The whole set is easy to move, assemble and store. The supplier is professional with fast reply and thoughtful service. I am very satisfied with this purchase.

Harry Mitchell

Canberra, Australian Capital Territory, Australia

Very happy I chose this linear steel grating! The design is practical, the gaps are well spaced for quick drainage, and it’s really easy to install. The material quality is top notch, tough and weather-resistant for long outdoor life. The service was warm and professional, always quick to reply and helpful. Will absolutely order again for our next project.

Luke Taylor

Queen Street, Brisbane, Queensland

Amazing pets mesh! Durable, lightweight and extremely functional for all pet containment needs. The construction is solid, not easy to fray or deform. Perfect for garden fencing, animal pens and outdoor protection. Great communication throughout the whole order. 100% trustworthy supplier, love this product!

Jessica Allen

Tucson, Arizona

Perfect fence for my outdoor space! Very stable, easy to assemble and incredibly durable. The build quality is amazing, no bending or damage at all. It greatly improves my yard security and overall appearance. Friendly support and fast delivery, 100% recommended.

Thomas King

Perth, Western Australia, Australia