Discover the process of creating a soakaway: an economical and efficient method to safeguard your residence and parking area from waterlogging
In the UK, one in eight adults with a garden has experienced the devastating impact of flooding on their green spaces, according to recent research. To combat this issue, a soakaway can be an effective solution for managing excess rainwater. Here's a step-by-step guide on how to build a soakaway.
First, you'll need to gather your materials. To build a soakaway, you'll need a shovel or mini digger, pea shingle, soakaway crates or rubble, a silt trap, geotextile membrane, gravel, and cable ties (if needed to attach crates together). The soakaway crates, which come in a 300 litre capacity, are of HGV load quality and can be used for driveways, lawns, and patios. They can be stacked together if necessary.
Before you start digging, it's crucial to conduct a percolation test to determine the suitability of the soil for a soakaway. This test measures the soil's infiltration or permeability rate. To perform a percolation test, dig one or more test holes in the proposed soakaway area, pre-soak the holes, fill the hole with water again to a known depth, measure the drop in water level at regular intervals, and calculate the percolation rate.
Suitable soil typically has a percolation rate between 20-60 litres/m²/hour or permeability greater than 6.8 mm/hour. Sandy and loamy soils usually have good percolation rates, while clayey or heavily compacted soils usually have low permeability and are unsuitable. Soils with very high permeability may risk groundwater contamination.
Once you've determined that the soil is suitable for a soakaway, it's time to excavate the site. If the soakaway is under a driveway, you may need to dig down at least 1.5m. The soakaway site should be clear of any underground services, including mains water pipes, gas pipes, and comms cables.
A geotextile membrane should be used to line the dug-out hole for the soakaway. The crates of the soakaway system should be attached together using clips or cable ties. A layer of pea shingle should be placed over the crates, followed by a layer of soil, when filling the soakaway pit. The soil layer should be roughly 4cm thick, but check what is recommended by the crate manufacturer.
It's important to note that a silt trap is recommended for a soakaway to extend its lifespan and help it stay efficient. The soakaway should be at the lowest point in the rainwater drainage system and should be positioned at least 5 metres away from the property or a retaining wall.
Lastly, keep soakaways away from wells or drinking water sources by at least 10 metres to avoid cross-contamination. Adding a layer of coarse sand or gravel around the pit may improve percolation if soil is borderline.
A soakaway is a hole dug into the ground, filled with rubble or specialist soakaway crates, which allows surface water to percolate back into the earth in a measured way. By following these steps, you can potentially solve the problem of waterlogging and allow excess rainwater to drain naturally back into the ground. Some soakaway kits come with a silt trap, geotextile membrane, and cable ties, and the assembly time is only 12 minutes.
- To manage excess rainwater effectively, you can build a soakaway, considering it an essential solution for homeowners with gardens.
- Gather necessary tools such as a shovel or mini digger, pea shingle, soakaway crates, a silt trap, geotextile membrane, gravel, and cable ties for a successful soakaway construction.
- Before starting the digging process, perform a percolation test to determine the soil's suitability for the soakaway, using the test's results to decide if the soil is suitable or if it needs improvements.
- Utilize a geotextile membrane to line the dug-out hole for the soakaway, and secure the crates using clips or cable ties.
- Place a layer of pea shingle over the crates, followed by soil, and ensure to check the recommended thickness from the manufacturer.
- To prolong the soakaway's lifespan and maintain its efficiency, incorporate a silt trap in its design, positioning it at the lowest point in the rainwater drainage system and keeping it 5 meters away from the property or a retaining wall.
- For better water percolation, consider adding a layer of coarse sand or gravel around the pit if the soil is borderline, and ensure to place soakaways at least 10 meters away from wells or drinking water sources to avoid cross-contamination.
