Simple French Drains

If you buy a new home, you may have the landscaping professionally installed, or you might decide trying to do it yourself. Either way, most new home owners eventually have to correct drainage problems that create excess ground water on their property. There are different solutions, but the best way to divert this excess water away from the foundation of your house, low lying areas on the lawn, or flooded flower beds is to use simple French drains.

What are French Drains?

A French drain is a trench filled with gravel that redirects surface water away from the areas where it can cause damage to landscaping or structural foundations. It is the least expensive and most unobtrusive way to solve minor drainage problems caused by land that slopes in the wrong direction.

How do I get Started?

Determine a place on your property where the water running off the slope could be diverted. The ideal French drain leach field would be an out-of-the-way area with sandy soil, through which the water could percolate harmlessly. However, if you don’t have such an area on your property, you will need to talk to your neighbors.

Since you are digging a trench to reroute existing water to somewhere new, you have to make sure that it is going to a spot where it won’t cause anyone else drainage problems. If your neighbors are okay with your water plan, the next step is to consult the local utility companies to make sure that you aren’t digging up any power lines.

Measuring and Digging Trenches

Find an area along the slope you wish to drain that is free of obstructions. In order for the French drain to work, it must be on a 1% grade, which is a one foot drop for every 100 feet in length.

Stake a post at both the beginning and the end of where you want to dig. Then tie a string tightly between the two posts. This will be your guide for digging.

As you make your way down the hill, you will be able to measure the depth of the trench against the string to see if you are achieving the proper grade.

The trench should be about six or eight inches wide and twelve inches deep, depending on the magnitude of the water problem. The trench can be dug with a common spade or shovel, but it will be easier and neater to go and get a trencher from a local rental shop.

Once you are finished digging the trench, it needs to be lined with landscape fabric. This will keep the gravel from mixing with the dirt which will cut down on water flow.

Shovel a layer of coarse gravel over the landscape fabric and then fold the excess fabric over the top of the gravel to form a tube. Shovel a layer of sand over the tube and cover it with another layer of landscape fabric. Add four inches of top soil and lay sod on top of that.

This completes your simple French drain. The planning of where the water is going to go is the most important part of this project. If the way you route the water sends it to the wrong place on a neighboring piece of land, you will have to correct the flow of the water or face a possible law suit if your drainage causes damage to your neighbor’s property. The hardest part is definitely the digging, but rental equipment or hiring a professional will help if digging the trench yourself is absolutely out of the question.