How deep should you dig 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.

How many inches of gravel do I need for a French drain?

Pour and compact about 3 inches of gravel or landscaping stone along the bottom of the trench. This will act as bedding for the drainage piping.

How deep should a drainage trench be?

A drainage trench should be at least 18 inches deep. This allows you to install a gravel bed, as well as an adequately-sized pipe to carry away water. It also allows you to cover the pipe to protect it and make your drainage trench an attractive lawn feature.

How deep should drain pipe be buried?

Maintaining a depth of 12 to 18 inches is best for drain pipes, but the depth of the pipe may vary in order to maintain a downward slope, which is critical for proper drain functioning.

How much dirt do you put in the top of a French drain?

How deep should a French drain be? A French drain should be at least 6-8 inches deep to protect it from erosion and digging. However, the depth of a French drain will vary and may need to be several feet under the ground depending on the slope needed to ensure water flows properly through the drainage pipe.

How Deep

Does French drain need an outlet?

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. You can construct the drain to accept water along its length, and disperse it underground.

Why do you need gravel for a French drain?

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.

What is the best pipe to use for a French drain?

French drains are typically constructed with black corrugated pipe, but there are arguments that favor using white PVC pipe for the job, as well.

Can a French drain be too deep?

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.

What size gravel is best for drainage?

In general, you want to aim for ½ inch to 1-inch gravel for drainage. Areas that will see especially heavy flow may need larger gravel. Or, projects without drainage pipes may also need larger gravel. For example, a French drain without perforated pipe needs 1 ½ inch gravel.

Do you have to put gravel on the bottom of a French drain?

French Drain Gravel

The upper 12 inches above the pipe shall be filled with native soil, to avoid having crushed stone over the perforated pipe that could damage the pipe. It is important to place the gravel around the pipe because they will filter any sediment that the geotextile is not able to remove.

What size rock is best for French drain?

Use Natural 1-1/2" round rock for best drainage. Washed rock is ideal. Avoid small pea gravel as the spaces in between stone is smaller minimizing flow rates. Avoid Crushed Rock (minus) that compacts and has "fines" that will clog pipe inlets.

How much river rock do I need for French drain?

How much gravel do I need per foot of French drain? You would need around 0.72 cubic feet of gravel per foot length of French drain for a typical French drain width of 10 inches and a depth of 12 inches if you're using a 4" drain pipe.

Should I use landscape fabric in French drain?

Non-woven geotextile fabric is the best choice for drainage applications where water flow through (permeability) is the main concern. Non-woven landscape fabric is commonly used in French-drains, drain-fields, and erosion control.

Do you backfill French drain?

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.

Where should French drain end?

End the French drain at a low-lying water source, such as a pond or lake, if you have one on your property. If you do end your French drain at a pond or lake, make sure the opening of the French drain sits above the water level. The water will roll down the drain and empty harmlessly into the water.

How deep should a perimeter drain be?

You'll have to dig a trench around the perimeter of your footing. This trench must be at least two feet wide and six feet deep. For a slab-on-grade home, the trench can be as shallow as two feet.

Does a French drain really work?

French drain systems are incredibly effective because, unlike typical surface drains, they collect water over the entire length of the drain as opposed to one dedicated area. The force of gravity helps to guide water along a reliably smooth path to the desired discharge point.

How long do french drains last?

Generally speaking, a French drain will last approximately 30 to 40 years. However, the above-mentioned factors may shorten its life cycle and it must then be replaced by a team of foundation experts.

Can I run a downspout into a French drain?

A French drain is actually a network of pipes laid in trenches dug beneath the ground through which water runoff can flow. This structure can be attached to your downspouts and will work seamlessly with your existing gutters.