Exactly as its name implies, a land drain is designed to drain excess water away from domestic gardens, fields or any other grassed areas. Installing a perforated land drain pipe allows water to be collected and carried to a soakaway, water course or surface water drain – preventing the ground from becoming waterlogged.
The question is, how easy is it to install one?
A land drainage pipe can be installed almost anywhere, but particularly in areas that saturate easily. It can also be placed where the soil has performed badly in a percolation test.
Whilst you should always contact your local drainage company to conduct a percolation test, and seek expert advice, you will also need to check with the local authority to make sure it’s ok to install the land drain, otherwise, you could be faced with a hefty fine. Once you get the green light, you’re good to make a start – and here we look at how to do it in 5 simple steps:
Step 1: The perforated land drain pipe should be laid into a trench that is approximately 250mm wide. In terms of depth, 900mm is ideal but, this can vary depending on the soil makeup.
Step 2: Make sure that the sides of the trench are vertical or tapered towards the bottom.
Step 3: After digging the trench, line the base with geotextile membrane and save some to cover the top of the backfill material at the end. This membrane will prevent the soil from being washed into the drain and clogging up the perforations in the land drainage pipe. It also ensures the gravel remains within the trench.
Step 4: The penultimate step is to lay the land drain onto a bed of pea shingle. This material will also be used to backfill the trench, once the pipe has been installed, up to a depth of 150mm from the surface.
Step 5: Use the remainder of the geotextile membrane to cover the top of the pea shingle and re-lay the soil and turf that was excavated at the start.