French Drains – What Are They and Why Do You Need Them?

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french drain

Do you have a wet spot in your yard that never seems to get completely dry unless it’s the dead of summer? Does a hard rainstorm completely wash out a portion of your lawn or gardens? You might be a perfect candidate for french drains.

What are French Drains?

At their simplest, french drains are simply ditches on the downward slope of a hill or embankment that have gravel in them. The downslope, as well as the gravel, allow water to flow down and drain easily and evenly through the rock as opposed to sitting on top of the soil. Their origins may be french, but the name comes from Henry Flagg French, who popularized the technique of moving water in 1859.

These drains are commonly used inside homes as part of a sump pump system. However, they have plenty of applications outside your home as well, in your yard, along the side of your driveway, or even next to walls that are already built.

Do You Need One?

Virtually every yard would benefit from a french drain. Unless your home is on top of a giant hill, a french drain can help control and move water away from areas that you want to keep dry. Even if it is on a large hill, the areas at the bottom will get soggy, so french drains are a great option.

How Do They Work?

French drains are simple to install, but require extensive labor. First, a trench about two feet wide is dug that will hold the piping. The trench should be angled downhill toward where it will drain – you’ll want to stick to about one inch of drop for every eight feet in length.

Then, gravel is placed on the bottom of the trench and on top, is either one or two pipes with multiple holes and openings. These allow water to enter then flow down to the mouth of the pipe. PVC lasts longer and can be cleared much easier. Normal corrugated pipe, however is easier to lay and much cheaper. You’ll have to decide what works best for you.

Next, the pipe is laid in the trench and rocks are piled over top with landscaping fabric wrapping around the area to keep out dirt and debris.

Finally, backfill the trench and ensure that the outlet is in an easy place for the water to flow out of the system freely.

Can I Do This Myself?

The short answer is yes, you can install a French drain yourself. However, digging the trench may prove very difficult and ensuring that the slope of the drain is correct can be hard for a novice to calculate. At the very least, the job of digging should be left to professionals or heavy equipment.

As with any project that requires digging into the ground around your home, be sure to check with your local utilities to mark underground pipes and wires.


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