Question: What Size Gravel Should I Use For A French Drain?

Do holes go up or down in a French drain?

When you lay your PVC pipe, the rows of holes should always be facing the downward position.

You want to keep the water level in your French drain as low as possible at all times, and you can’t achieve this if the holes are facing upwards or sideways..

Can I cover a French drain with dirt?

The simplest drain is a classic French drain, which is nothing more than a trench filled with coarse stone or gravel. A 2–4% slope is adequate to quickly move water away from trouble areas. The drain can be left open or, if aesthetics are a concern, can be covered with a couple of inches of topsoil and sod.

What is better than a French drain?

If you have a negative sloped yard (which slopes toward your foundation), a surface drainage system is a better choice than a French drain. Sloping of more than 1”-1-1/2” on a 10′ run can result in excessive amounts of water seeping beneath your house.

How deep should a French drain be?

About 8 inches to 2 feetFrench 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.

Can you install a French drain without gravel?

Related To: The old way of installing French drains is to do it without the gravel and the fabric. Without the gravel and the fabric, however, the drain can clog up with sand and soil over time.

Does a French drain need an exit?

Most descriptions of a french drain involve a slotted or perforated pipe, a trench, geotextile fabric and gravel backfill. To operate properly, the drain must have adequate slope and a place to open onto the ground, into a drain pipe or somewhere else where water can exit.

How much gravel do I need for a 100 foot French drain?

The volume of the drain is the volume of the “box” that is 100 ft long by 6 inches by 18 inches. That’s 1200 x 6 x 18 = 129600 cubic inches. The difference between these will be the volume of gravel you need. Thats 129600 – 15080 = 114520 cubic inches.

Do I need gravel for solid drain pipe?

In this system, the pipe is solid, and not perforated, so there’s no need to provide gravel for drainage along the length of the drainpipe. One advantage of a smooth-wall pipe is that it will drain water quickly, and if it gets clogged, you can use a drain snake to clean it out.

What is the difference between a French drain and a trench drain?

The terms rhyme, they both involve trenches, and French drains aren’t really French. The defining difference is very simple, however: Trench drains are surface structures while French drains are subsurface ones. Let’s look at how they both work to keep water flowing offsite.

Does a French drain need to be sloped?

French drains need to have a slope of at least 1 percent, so the force of gravity will work for you. This means that the drain should slope down a total of at least one inch for every 10 feet of pipe.

What is the best pipe to use for underground drainage?

Plastic pipesPlastic pipes are the preferred drainage pipe due to its versatility and availability. It is lightweight and easy to use for installation. There are several plastic drainage pipes to serve different purposes and they come in various diameter sizes to accommodate different amounts of water.

How do I dig a French drain around my house?

How to Install a French DrainCall the 811 hotline to have underground utilities marked.Dig the trench system.Line the trench with landscape fabric. … Add 2 to 3 inches of gravel to the bottom of the trench.Lay the drain pipe in the trench, with the drain holes facing down.More items…

Why do holes go down on French drain?

A review of installation instructions from several State DOT manuals reveals that the holes should be down (i.e. placed facing the bottom of the trench). The reason is that this allows the water to enter the pipe and drain from the soil at the lowest level.

Is pea gravel good for drainage?

Since it has a smooth finish, pea gravel is also regularly used for walkways, dog runs, playgrounds, patios, and a variety of other high-traffic areas. Like crushed stone, pea gravel can also be used for underground projects, such as drainage and pipe bedding.

How far should a foundation be from a French drain?

A French drain consists of buried perforated pipes slightly sloped to easily channel water flow, in this case, away from the house foundation. Start by digging a 2-foot-deep-by-18-inch-wide trench 2 feet or so away from the foundation at the highest point where the rear yard meets the foundation.

What size gravel is best for French drain?

For the best drainage, look for coarse washed rock (gravel) that is screened, with a stone size of 1/2 to 3/4 inch. Smaller rock with fine particles could clog the holes of the drain pipe. Pea stone works, but the smooth stones settle together and don’t move as much water as coarse rock.

What type of rock should I use for a French drain?

The stone should be no less than ¾” and dense (we suggest Granite, or River Gravel) so it will allow good water flow. Lime Rock, although inexpensive, is a poor choice for a French Drain because it will begin to deteriorate over time and eventually begin to pack down and restrict flow.