How to make a french drain

French drain depth: About 8 inches to 2 feet deep should be sufficient for many water-diverting projects, though related systems, such as those built around foundations and sub-ground living spaces, as well as the bases of retaining walls, may be deeper.

A properly designed French drain system does not require an outlet. The water will simply soak into the soil as it flows along the perforated pipe. In fact, a French drain doesn’t require an inlet on just one end either.

Swales or Valleys

Swales, also called valleys, are an alternative to French drains that capture and divert rainwater. Swales are shallow ditches that do not contain pipes. You can usually find them along a property’s edge, following the natural grade of the land to direct runoff to ditches or wooded areas.

FILLING AND PIPING A FRENCH DRAIN

Choose one of two types, either rigid PVC with predrilled holes or flexible drain pipe cut with slits. PVC lasts longer, and if you encounter a clog, it can be cleaned with pressure or a plumber’s snake.

Installing a French Drain Without a Pipe

When you omit the pipe from a French drain, you‘ve basically got a trench drain. If your soil drains well, you can simply dig the trench and cover the bottom with 3 to 4 inches of 3/4-inch drainage rock, depending on the depth of the trench.

Gravel used for this layer is typically 1/2 inch to 1 inch across — the larger it is, the better the water flow and less chance of clogs and blockages. For a French drain without a perforated pipe, opt for even larger gravel, such as 1 1/2 inches across.

Aside from what we’ve listed here, the difference between a French drain and a trench drain is that a French drain is used for water that is underground while a trench drain diverts excess water from a surface.

Generally speaking, a French drain will last approximately 30 to 40 years.

Why Good Drains Go Bad

Over time, a French drain may become clogged. Tiny soil and clay granules slip through the pores of the landscape fabric and gradually build up inside the pipe. Another common cause of French drain clogs is root intrusion from grass, shrubs, and trees.

If you’re dealing with a wet basement or a soggy lawn, you might want to look into installing a French drain. While it’s not necessarily a “quick fix,” a French drain can be a smart investment to keep your home and yard dry.

Can I cover a French drain with dirt? Because a French drain has holes throughout the pipe which allow it collect water, you should not install dirt on top of the drain pipe. Installing dirt will clog the pipe and the holes, rendering it useless.

Putting one in your yard involves digging a trench about 2 feet deep then lining it with water-permeable landscape fabric. Once the fabric is laid, add a few inches of gravel and lay down a drainpipe that is punctured with several holes. Once the pipe is laid, you’ll add more gravel on top, then add sod over it.

One day that soil has all come together and there are no more air pockets. That’s the number one reason for yard drainage failures. And even if they’re using shovels, don’t let them put the dirt that they’re digging out back in. You have poor soil if you have a drainage problem.

If you’re uncertain where the drain starts, try looking at the highest point of your yard, since the design of the French drain is to help water run downhill. Step 2: Use a garden hose to run water down the French drain. If you notice the water backing up instead of running straight through, it’s clogged.