How to install a French drain

It rains a lot in Britain and this may seem like a good thing for our gardens but for many this precipitation is the source of undesired ponds. If there are large sources of water forming on your lawn then you may need a drainage system inserted.

Okay, so you are in need of a French drain –and no this isn’t plumbing from France. You want to save some money by fitting it yourself but you’ve never done this before. Here’s a step-by-step guide of how to install a French drain, we hope it helps.

What is a French drain?

A French drain, also known as a weeping tile, is a simple construction that has big effect. A French drain is a dug trench filled with gravel or small rocks for redirecting unwanted groundwater. A perforated pipe will be placed amongst the stones to collect and channel the water.

A French drain is used to stop excess water from penetrating and damaging building foundations and to relieve water which forms pressure behind retaining walls.

How to install a French drain

1. Locate the area in which you want to reroute water and decide on the best direction to angle the flow. This should be on a slight downward slope and make sure it will not flow towards any neighbouring properties.

You can make sure this is in a straight line by placing a peg at the start and end destination and joining with string. This will act as a ruler.

1. Using a brightly coloured waterproof spray paint mark out the drainage route.
   Measure out the stretch of highlighted ground so you know how much deep guttering you will need to buy.
   Before digging the trench make sure there is no underground cables or existing pipes in the area. Dig out the trench saving the dirt and turf you remove. Your trench should be 6 x 24 inches.
   Add your gravel. This should be 2 to 3 inches deep.
   Place the drain pipe on the gravel and cover with landscaping fabric. Leave an excess overhang of the fabric on the sides. This fabric is used to stop dirt from blocking the pipe.
   Cover with gravel and fold over the ends of the fabric. Make sure to leave a 3 inch gap between the gravel and the ground surface.
   Cover with the dirt you saved earlier and replace the turf. Add some of the gravel or stone around the opening of the pipe in order to sturdy the ground around the opening.

Do you think you can follow these instructions? Remember when digging your French drain to do so in dry weather so the ground is firm. And always check with your local council that they do not have any pipes or cables running beneath your garden. Best of luck with your home improvement!

For more information on underground soil and waste products take a look at our specific products found in the plastics section of the site.