Channel Drains & Their Covers: A Comprehensive Guide to Materials

Channel drains play a vital role in surface water management, efficiently collecting and directing water away from areas that may be prone to flooding or water retention. Selecting the right material for channel drains and covers is essential for ensuring efficient water management and long-term durability. Whether for residential patios, commercial driveways or heavy-duty industrial zones, understanding the properties and load ratings of different materials will help you make an informed decision. By choosing the appropriate combination of drain body and cover, you can ensure optimal performance and longevity for your drainage system.

This guide explores the most common materials used in channel drains and covers, talks about load ratings and gives examples of typical situations where each is most suitable.

What Materials Are Channel Drains Made from?

The body of a channel drain is installed below ground level, where it acts as an open-topped linear drain to accept water from a large surface area. It needs to be sturdy and durable enough to withstand pressure not only from the surrounding substrate but also from traffic passing over it. The best channel drain material will therefore be determined by where it is installed.

· Polypropylene (PP)

Polypropylene is a lightweight and cost-effective material known for its corrosion resistance. Polypropylene channel drain is commonly used in residential and light commercial applications such as driveways, patios and gardens. However, its structural strength is limited, making it unsuitable for heavy loads – it is generally only rated up to A15, which means it will support loads of up to 1.5 tonnes.

· Polyethylene (PE-HD)

Polyethylene offers similar benefits to polypropylene but provides slightly better impact resistance and durability. Polyethylene channel drain remains lightweight and UV-resistant, making it a suitable option for driveways and light commercial use. With a load rating of up to B125 (12.5 tonnes), this is a good choice for areas handling light vehicle traffic.

· Polymer Concrete

A composite material made from resin and aggregates, polymer concrete offers excellent strength, smooth water flow and high chemical resistance. Polymer concrete channel drain is commonly used in car parks, light industrial zones and other areas with moderate to heavy traffic. It typically has a load rating of between B125 and D400 (12.5 to 40 tonnes), making it a durable and versatile option.

· Concrete

This is the traditional choice for large-scale drainage applications, offering high durability and cost-effectiveness. Concrete channel drain is commonly found in industrial and public infrastructure projects where heavy loads are a concern. Most concrete channel drains have a load rating of D400 and above, ensuring they can handle high-traffic areas with ease.

· Stainless Steel

Stainless steel is known for its corrosion resistance, sleek appearance and durability. It is frequently used in environments that require high hygiene standards, such as food processing plants and pharmaceutical facilities. Load ratings for stainless steel channel drains vary depending on design, but they are typically suited for commercial and industrial applications.

Where a channel body is constructed from a material with a varying load rating, it is always advisable to check the product’s technical specifications.

Channel Drain Cover Materials

The cover or grating of a channel drain is a separate component that permits traffic to pass over the drain while allowing water to filter into the channel. As the cover is also load-bearing, the material used to manufacture it and its load rating will also depend on the environment in which it is being installed.

· Plastic (Polypropylene or Polyethylene)

Plastic covers are lightweight, cost-effective and non-corrosive, making them a suitable option for pedestrian areas and light-duty residential applications. These covers generally support loads up to A15

(12.5 tonnes), making them ideal for gardens, patios, and walkways. As with the channel drain itself, polyethylene offers enhanced resistance to physical stress and UV radiation from sunlight.

· Galvanised Steel

Galvanised steel covers provide durability and rust resistance at an affordable price. They are commonly used in driveways, car parks and light industrial zones, supporting loads ranging from B125 to C250 (12.5 to 25 tonnes). Their combination of strength and affordability makes them a popular choice for medium-duty applications.

· Ductile Iron

Ductile iron is extremely strong and capable of withstanding heavy loads. It is the preferred material for industrial zones, heavy vehicle areas and docks, with load ratings ranging from C250 to F900 (25 to 90 tonnes). Its superior strength ensures longevity and reliability in high-traffic environments.

· Stainless Steel

Stainless steel covers offer high corrosion resistance and an aesthetically pleasing finish. They are frequently used in high-end commercial projects for their attractive finish or in areas such as food processing plants and pharmaceutical facilities where hygiene is paramount. Depending on the design, stainless steel covers can support heavy loads.

· Composite Materials

Composite covers are gaining popularity due to their lightweight, eco-friendly and non-corrosive properties. These covers are versatile and can be used in various applications, typically supporting loads between B125 and D400 (12.5 to 40 tonnes).

As with the channel drain body, if a cover material may potentially be rated differently, we would recommend checking the product’s technical specifications.

Channel Drain Load Ratings and Material Suitability

· A15 (1.5 tonnes)

A15-rated polypropylene and plastic channels and covers provide an ideal solution for pedestrian areas such as gardens, patios, and walkways. These materials are lightweight, cost-effective and resistant to corrosion, making them a practical choice where only foot traffic is expected. Their structural integrity is sufficient for areas with minimal load-bearing requirements, ensuring effective water drainage without unnecessary expense.

· B125 (12.5 tonnes)

Driveways, car parks and other areas with light vehicle traffic require stronger materials that balance durability and affordability. The combination of a polyethylene channel drain and a galvanised steel cover is well-suited for these applications, offering a combination of impact resistance, UV protection and cost-effectiveness. These materials can withstand the pressure of small vehicles while maintaining their integrity over time.

· C250 (25 tonnes) to D400 (40 tonnes)

For roadsides, loading bays and areas that frequently experience heavier traffic, a polymer concrete channel drain will provide the necessary strength and durability, offering superior resistance to wear and environmental factors while maintaining smooth water flow. Ductile iron, galvanised steel and composite covers are also commonly used in these settings, providing adequate support for commercial and industrial zones where structural integrity is crucial.

· E600 (60 tonnes)

Industrial zones, warehouses and smaller docks require materials that can support extreme loads while resisting environmental wear and chemical exposure. Polymer concrete, reinforced concrete and ductile iron drains are optimal choices for these high-intensity applications. Ductile iron covers ensure longevity and resilience against heavy-duty machinery and frequent vehicle movement.

· F900 (90 tonnes)

Airports, large commercial docks and high-load industrial sites demand the highest level of load-bearing capacity, so concrete is the most common material used for channel drain bodies in these situations. Ductile iron is the preferred material for a channel drain cover due to its exceptional strength and ability to handle extreme weights. While this provides the necessary durability for environments where constant

heavy loads and harsh conditions are the norm, stainless steel may be used as an alternative in marine or highly corrosive environments.

We hope you found this guide to channel drains informative and useful. If you have any further questions or would like to discuss a specific project with the experts at Drainfast, please call 01420 555600 or email [email protected]. You can also view a selection of our channel drainage products on our website.