What Drainage Do I Require On My Driveway?

When it comes to drainage for your driveway, it’s crucial to ensure water is properly managed to avoid flooding, erosion, or damage to the surface over time. The right drainage system will depend on factors like the slope of the driveway, the type of surface, and local regulations. Here are key aspects to consider:

1. Slope and Gradient

• Proper Slope: Ensure your driveway has a slight slope (typically around 1-2%) away from buildings or other structures to direct water toward drainage points.

• Avoid Water Pooling: The driveway should be designed so that water doesn’t pool, creating hazards or damaging the surface. Make sure there is a gradual slope, especially at the edges or near entryways.

2. Permeable Surface (SUDS Compliant)

• If you’re using materials like resin-bound gravel, permeable block paving, or gravel, these surfaces allow water to drain through them into the ground, reducing the need for complex drainage systems.

• These surfaces often meet SUDS (Sustainable Drainage Systems) regulations, which aim to reduce runoff and allow rainwater to naturally infiltrate the ground.

3. Drainage Channels & Channels

• Edge Drains: These are narrow channels placed along the edges of your driveway to catch water runoff and direct it into a drainage system or soakaway.

• Linear Drains (or Aco Drains): These are commonly used along the sides of the driveway to collect surface water, especially if the driveway is sloped. The drains are typically made of plastic or metal and can be discreetly installed to blend with the driveway surface.

4. Soakaways

• Soakaways are underground structures that allow water to soak into the ground rather than running off. A soakaway is usually a gravel-filled pit or a specially designed crate system, which helps manage surface water runoff.

• These are particularly useful for impermeable surfaces like tarmac or concrete, where water can't easily pass through the material.

• For resin-bound gravel, a soakaway might not be necessary because the material allows for water to naturally drain through it.

5. French Drains

• If water tends to accumulate in specific areas of your driveway, a French drain can be a good solution. This consists of a trench filled with gravel and a perforated pipe that redirects water away from the driveway to a drainage point, such as a storm drain or soakaway.

6. Guttering and Downpipes

• If your driveway is attached to a property, ensure that guttering and downpipes direct water away from the house and driveway.

• Consider adding drainage pipes that carry rainwater from the gutters to a safe location, such as a soakaway or storm drain.

7. Surface Drainage

• Depending on the surface you choose for your driveway (tarmac, concrete, resin-bound gravel), you may need to install a sub-base with a proper drainage layer. This helps prevent water from pooling under the surface and causing damage.

  • For concrete or tarmac, a permeable base layer and additional drainage systems (like channels, soakaways, or French drains) may be required.

  • For resin-bound gravel, the material itself allows water to flow through, but a properly designed base (with a suitable drainage layer) is still important to ensure efficient water flow.

8. Stormwater Management (Local Regulations)

• Check Local Regulations: In some areas, especially those governed by SUDS regulations, you'll need to ensure that your drainage system meets local requirements. For example, rainwater may need to be directed to a permeable area or a soakaway instead of running directly into the street drainage system.

• Permeable Driveway: If you're installing a permeable driveway (e.g., resin-bound gravel), it may meet the required drainage standards, but you still need to ensure it's installed properly to allow for water flow.

9. Maintenance Considerations

• Ensure that your drains, channels, and soakaways are regularly maintained to avoid blockages. Clean out debris from edge drains, gutters, and any drainage channels periodically to keep water flowing freely.

Summary of Drainage Options for Driveways:

• For Permeable Surfaces (e.g., resin-bound gravel, porous paving): Ensure proper sub-base and base layer with sufficient slope for water to drain naturally. Soakaways or French drains may still be required in areas with high water volume.

• For Non-Permeable Surfaces (e.g., tarmac, concrete): You’ll need to incorporate edge drains, soakaways, and/or French drains to manage water runoff. Proper grading and slope are essential.

Final Thought:

A well-planned drainage system will not only protect your driveway but also contribute to the longevity of the material and prevent any future issues like flooding, pooling, or cracking. Always consider local regulations and potentially consult with a professional to ensure you design a system that meets both your needs and compliance standards.