How to Install Properly a French Drain

The French drain is a system that is essential for removal of excess water from points that have saturated soil. The concept of French drains is simple: French drains are just trenches that are full of gravel and sand is put on top of the gravel. In most recent installations, French drains are including pipe, but traditionally the design of French drain was just a trench that was filled with gravel and sand. French drains come with many advantages such as keeping your basement dry. If you want to install one or are hiring a contractor to install or replace your French drain, read on to discover how it shoud be properly installed.

Digging the trench

The starting point is digging a trench. The trench may vary in the width and depth depending on your needs.

Proper slope

Grading is essential, and you should make sure that there is adequate sloping so that the water can flow with ease and towards the right direction. You must ensure that there is a slope existing because it will serve to carry the water in the direction of your choice. You must ensure that at least the sloping is 0.5 percent.

Filling with gravel

After digging the trench, you are ready now to add gravel to the trench and cover some inches of the surface. The gravel that you used ranges from 0.5 to 1 inches in size.

Add a layer of sand

Once you have added gravel on the trench, you can now add up to 4 inches of course sand. Sand is essential because it will enable turf to grow making the trench not to be visible. You should ensure that the sand is course so that water can drain through properly.


You can just allow turf to be grown on the sand, and it can spread depending on the type of turf. You can also use sod and lay it on the sand, but you should ensure that you wash the soil from the roots of the sod before you lay it to avoid contaminating the sand using fine soil.

Addition of drain pipe

You can follow almost a similar process and use a drain pipe, but in this case, you will need to lay up to 2 inches of gravel to the trench bottom. Here is where a perforated pipe will be allowed to rest. You should then ensure that the drain pipe is wrapped in filter fabric. You can then do finishing by adding gravel around the pipe and ensure that at least 1 inch of gravel surrounds the gravel to all sides.

If you are thinking of fixing a large area that is complex, you should think of hiring a professional who has the right experience for the job. Such a project needs proper grading and the right pipe sizes as well as proper design to ensure the system does not collapse. While you may fix a simple French drain when it comes to the complex project you need the help of qualified engineers and professionals.

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