A guide to channel drain installation

Surface water drainage systems heavily rely on performant channel drains in either plastic (HDPE or PP) or concrete. The channel drain is a crucial part of a drainage system. It also has other names such as trench drain, line drain, slot drain, or drainage channel. A channel drainage system:

  • Does not require deep excavation and, in some cases, may remain at ground level
  • Requires only a limited number of components, making transportation and installation relatively easy
  • Is easy to install and modify if needed
  • Eliminates the risks posed by water buildup and stagnant water while being an easy solution with a relatively low cost.

A channel drain system is also long-lasting, easy to maintain, and can help reduce soil erosion. Let's break down the steps and learn how to install channel drains.

The 11 steps needed to complete a channel drain installation:

  1. Dig a trench for the channels, at least 50mm deep and 100mm wide. The depth and width depends on the use. For example, a driveway drainage channel will require less space than an airport runway channel.
  2. Attach a string line to show the finishing height of the grate (around 2mm lower than the surrounding surface level).
  3. Factor in a 5mm fall for every 1m of channel drain length (1:200 ratio).
  4. Begin the installation of sections at the lowest point (where the section meets the drain). Use any section that requires cutting to length at the highest point, furthest from the drain outlet.
  5. Connect the channel drains through the connecting slots at the ends of the sections. Install sections with their grates in place to allow for height accuracy against the surrounding surface.
  6. Fit an end cap to the final section. The end cap should always feature at the highest point.
  7. Seal joints and end caps with a silicone sealant to improve durability, leak resistance, and performance.
  8. Attach the section to your underground drainage, allowing collected surface water and/or foul water to disperse.
  9. Prior to pouring concrete, protect the drainage channel grates with heavy duty masking tape. 
  10. Pour concrete to create a 2mm height difference above the grate section of the drainage channels.
  11. Wait 72 hours before putting weight on the concrete or moving the drainage channel grates to avoid damaging them. 
  12. The last and extra step is to periodically maintain and clean your drainage channels.

Despite its impactful role in caring for the land around it, people often overlook and underestimate surface water drainage. Failure of drainage systems is a common occurrence. Why do some surface water drainage systems fail? 

Occasionally, minor installation errors affect the overall effectiveness of the drainage system. The results can cause stagnant water buildup, water seepage, and eventual flooding. While this can cause significant damage to a building, it can also negatively impact the natural environment surrounding it.

The three most prominent mistakes during channel drain installation:

1 Planning errors

Good planning and knowing the terrain are important for installing channel drainage without any issues. For example, not following the trench size guidelines can lead to the failure of the drainage system.

Common planning mistakes can lead to drainage system failure. Not understanding the substrate or miscalculating the slope can reduce flow rate and cause blockages in the system. Talk with a skilled installer about how to install drainage channels for your specific project.


2 Unsuitable materials

Drainage pipes will experience a significant amount of weight and pressure when used regularly. This is especially true when vehicles pass over them frequently.

When selecting drainage channels, consider their load capacity, potential temperature changes, and the deterioration of channel integrity over time. There is a wide array and a variety of types of channels available. They come in various materials like concrete, plastic, cast iron, ductile iron, or even stainless steel.

Using plastic channel drains where concrete channel drains are necessary may cause the failure of the drainage system. Pay attention to the various types of channel drains and grates and their typical uses. Plastic channel drains have a number of benefits but cannot replace concrete channels where they are needed.


3 Incorrect water flow rate calculation

Incorrect calculation of water output can lead to choosing narrow channels and pipes. These narrow channels and pipes may not efficiently dispose of surface and foul water. As a result, blockages can occur, causing water to seep into the building's walls and structure.


Complying with the guidelines

EN 1433 is a European Standard that categorizes drainage channels based on their use and the strength of their grates, and rainwater drainage regulations in the UK follow similar guidelines. The standard applies to both pedestrian and vehicular areas and ensure the creation of a performant surface water drainage system.






A 15

kN 15

Areas used exclusively by pedestrians and cyclists.


B 125

kN 125

Pedestrian precincts, light vehicles, private car parks and drives in block paving. This class is for those looking to install driveway drainage on their properties.


C 250

kN 250

Parking areas, service stations (cars), and slow moving light commercial vehicles.


D 400

kN 400

Public highways, parking areas for all vehicle types.


E 600

kN 600

Industrial areas, heavy wheel loads, slow moving Heavy Goods Vehicles and forklifts.


F 900

kN 900

Airport runways, very heavy duty industrial and military installations, service yards and lorry parks.



Calculation of the Dakota Group's  Pegasus and Taurus drainage channels' flow rates:


Dakota Group is a building materials supplier that serves primarily the EMEA region. As a leading European supplier of building materials, we offer a range of drainage supplies that work together within highly performant systems. We have established ourselves as a reliable drainage supplier, with over four thousand customers that choose the products from our Drain catalogue.

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