what size gravel is best for french drain

French Drain Gravel Size Guide

• Getting Started. Gravel size and rock type is something that homeowners do not think about until it is too late. ...
• Recommended French Drain Gravel Size. The best gravel size for french drains is small rocks and pebbles .5″ to 1″. ...
• Recommended French Drain Sand Size. ...
• Common Gravel Sizing Problem. ...

Full Answer

What size rock is best for French drain?

We recommend putting a layer of sod and larger pieces of rock around the entrance and exit for extra protection The best gravel size for french drains is small rocks and pebbles .5″ to 1″. Gravel this size is size enough to fit in the drain lines and big enough to properly filter the water.

What gravel is best for drainage?

What Size Stone is Best For Drainage?

• When it comes to planning for water runoff, the best types of drainage gravel are:
• #3 Crushed Stone: Best for drainage ditches such as french drains. Also used for a base when constructing a gravel driveway.
• #57 Crushed Stone: Best for aboveground areas that require good drainage, such as paths and runoff trenches. ...

How would a French drain work without a pipe?

How do you dig a trench for drainage?

• Fill the trench with additional gravel.
• Line the trench with bricks or stones.
• Cover the trench with soil—you can even plant grass on top!

What size stone is best for drainage?

What Size Rock is Best for Drainage?

• Use large to medium-sized rock.
• Landscape gravel, crushed stone #3, and 3/4 inch gravel are great for drainage.
• Choose an angular rock that avoids compaction.
• Do not use sand, round gravel, or small rocks. These drain poorly and are prone to sliding.

Is 57 gravel good for French drain?

Washed clean stone with an average size of 3/4 inch. This is used as drainage stone inside of French drains and in the back of retaining walls and for gravel driveways.

Can you use gravel for a French drain?

Hard rocks such as granite or river gravel prove viable options for a French drain because they won't break down over time as much as other rock varieties, such as sandstone and limestone.

Is bigger gravel better for drainage?

Size Matters Larger-sized gravel will be more ideal for drainage. Stones with a size of half an inch to one inch across are the right size for blocking debris, yet allow for water flow. Larger rocks won't accidentally become compacted during heavy flows.Mar 15, 2022

What kind of gravel is best for a drainage ditch?

Add Gravel For best drainage, use large rock, such as #3 crushed stone which ranges from 3/4 to 2 inches in size. Alternatively, 3/4 inch gravel is adequate. Pour 8 inches of gravel into the bottom of your drainage trench, atop the landscape fabric. Use large-to-medium-sized rocks, crushed stone #3, or 3/4 inch gravel.

How deep should a 4 inch French drain be?

The trench should be about 18 inches deep and 9 to 12 inches wide. 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.

How much gravel do I need for a 50 foot French drain?

To calculate gravel needed for a 50′ french drain, multiply the length of the trench by the width and depth. If you plan to lay down 4 inches of gravel, multiply 50 feet x 4 inches = 200 cubic feet.

What kind of stone do you use for a 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.Mar 26, 2019

What is 20mm gravel used for?

Gravel, also known as garden shingle, can be used to finish a variety of garden or landscaping projects including driveways, pathways, rockeries, borders, and water features.

Can you use pea gravel for a French drain?

Do NOT Use Pea Gravel, Pea Pebble, Pea Stone When Building a French Drain. When building a French drain, you want to use a coarse rock that has been screened and washed. The rock that you see in this French Drain is 3/4″ and larger. You end up with large voids that'll move far more water.Apr 27, 2018

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.Feb 15, 2021

What drains better sand or gravel?

Sand compacts and retains moisture, therefore it does not drain as well as gravel. Although sand is not the best choice for back-filling a French drain, it does work well for some other types of drainage systems.

Should I put rocks in my ditch?

The bottom line, according to this Do It Yourself article, is that drainage ditches exist to prevent water buildup on your property. Lining your small trench with natural stone helps shape the ditch. Stones will also slow the growth of grass and weeds, which can in turn slow the drain of water.Aug 22, 2018

What is a French drain?

The bottom of the trench needs to have enough room to let water flow – without being packed in too tight! Remember, a french drain system is basically an underground river that lets you drain water into an area of your choosing – as long as you can slope the drain downhill.

How do French drains work?

French Drains are powered by gravity and work by using a slight 1 or 2 degree downslope. The layers of filler rock and sand help prevent blockages and protect the piping. We recommend putting a layer of sod and larger pieces of rock around the entrance and exit for extra protection.

Why is my gravel drain line clogged?

If your fill rocks and pebbles are too big water will drain too quickly from the line and there won’t be enough surface area for the top layer of sand to sit on top. If the gravel you choose is too small then it may compact in the drain lines and cause a clog.

How big should gravel be for French drains?

In french drains where there is not a pipe being installed, make sure to get even bigger gravel pieces. Try to get stones 1 and 1/2″ or bigger if possible. Additionally, it is wise to choose a harder rock for your base gravel so that it doesn’t wear down too quickly. Softer rocks that break down over time will become too small to properly drain ...

What is the purpose of gravel in a French drain?

In the set up of a french drain, gravel normally fills at least the bottom one third of the trench and a perforated pipe is laid on top of the gravel to allow even faster drainage in case the water is soaking into the ground faster than can be drained by the gravel. In french drains where there is not a pipe being installed, ...

Why is the French drain filled with gravel?

The gravel is one of the most crucial components to the french drain as it allows water that has soaked through the ground to be carried away down the slope of the french drain.

What is a French drain?

A french drain is a type of draining system that allows pooling water to escape to a lower point in the yard or the street. The main concept behind the design is a slightly sloped trench ...

What is the best stone for french drain?

Mexican Beach Pebble – This is product is an ideal choice for french drain gravel. The stones are roughly 1″ to 1 and 1/2″ wide and are already smooth which is ideal for water to run along the surface of the stone. Vigoro All Purpose Decorative Stone – This stone is not quite as wide as the beach pebble but is still a great option ...

How effective is a French drain?

A French Drain can be an extremely effective method for solving a drainage problem in your yard and maintaining the integrity of below grade concrete walls. If you determine that a french drain is right for you, make sure to do your homework in terms of best practices for installation. Additionally, make sure to locate any utility lines ...

How much does a French drain cost?

On average, french drains cost anywhere from $10-$15 per linear foot for materials and labor and the average total price is anywhere from $1,000 to $3,000. To get comfortable spending that kind of money, it is always best to know exactly what you can expect to get out of your investment. Here are some scenarios that french drains can be extremely ...

How deep should a French drain be?

In most installations, an 8-12″ wide trench will suffice. Enter the depth of the French drain. The standard depth is about 12″.

What is a French drain?

A French drain can be a great way to solve water pooling and water intrusion problems in your backyard. If you carefully estimate the gravel you will need using the French drain gravel calculator above and follow the tips outlined you can ensure a successful project.

How deep should a drain pipe be?

The standard depth is about 12″. On average this will allow for about 5″ above a 4″ drain pipe, and 3″ of top soil/grass above that. The depth may need to be increased if there are any humps or variability in slope of the area being trenched.

1. Pea Gravel

Pea gravel is generally about ⅜-inch in size and is often called pea shingle. It’s a very attractive gravel that comes in a variety of colors, including brown, blue, red, and grey.

3. River Rock

Just as the name suggests, the gravel used in river rock comes from the beds of rivers and streams. These stones are round and semi-polished from years of running water. They have a smooth texture, which means they tend not to stay put once you lay them down. However, they’re very attractive stones that are a great choice as a top layer.

5. Pink Quartz

If you’re looking for gravel that can add a dash of color while still maintaining good drainage characteristics, you might take a look at pink quartz. It’s available in several shades of pink, and it’s a very attractive-looking gravel that’s perfect as a top layer in many situations.

7. Jersey Shore Gravel

Jersey shore gravel is similar to pea gravel, though not available in as many colors. These stones are rather small, and they’re all shades of tan, white, brown, and gold; essentially, the color of beach sand. Jersey shore gravel features smooth rocks that don’t stay in place well.

9. Marble Chips

Marble chips are tiny little pieces of crushed marble, and they’re one of the most attractive top layers you could choose. This gravel glitters and sparkles in the sunlight, offering a unique and elegant look. The chunks are very small, so it’s only a good choice as a top layer.

10. Washed Clean Stone

Washed clean stone is essentially crushed stone that has been washed to get rid of any small chips and rock dust. This prevents it from compacting and ensures that it will always have great drainage. Because of this, it’s an ideal choice for bottom and mid-layers, though it does tend to be a bit pricier than non-washed crushed stone gravels.

What is drainage gravel used for?

Drainage gravel may be used for landscaping purposes. Drainage gravel is commonly used in variety of different applications, including landscaping and construction. Almost all types of gravel can be accurately described as loose rock.

What is gray gravel?

Gray crushed stone gravel is the most common type of gravel. As its name implies, shell gravel is made up of ground shells and other natural materials found on beaches and in coastal areas. This type of natural gravel can be used in the same manner as crushed rock and is most commonly used in the regions where it is produced.

What is river rock?

River rock is a popular type of smooth gravel and is usually 1 to 2 inches (approximately 2.5 to 5 cm) in diameter, though it can be found in larger sizes. This rock type is often installed in ponds or areas with minimal foot traffic. Pebbles are another type of rounded landscaping drainage material and are usually much smaller in size ...

How long is crushed rock?

Crushed rock is typically 1 to 2 inches in length. The crushed stone varieties of drainage gravel consist of shell gravel and crushed rock. The crushed rock is usually 1 to 2 inches (approximately 2.5 to 5 cm) in length, and is used for a number of purposes including driveway installation, building foundations, ...

What is gravel used for?

Not only do many types of gravel assist in water drainage, but gravel also enhances landscape design.

Can drainage gravel be used for mosquitoes?

This little known plugin reveals the answer. Poorly designed drainage areas can become a breeding ground for mosquitoes. Most types of drainage gravel are available in many different colors and sizes, with the exception of gray crushed rock.

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 much slope do you need for a French drain?

A French drain system will need to be installed with at least a 1% slope in the direction you need the water to flow. Without a slope, water will collect in the drainage pipe and sit there rather than move toward your pop-up valve or exit point.

What is a French drain?

While surface drains are appropriate when water is pooling in one specific, smaller areas, French drains are the answer to pooling water over larger stretches of your yard. For instance, if you have large amounts of water sitting along the property line in a side yard between you and your neighbor, a French drain is likely the solution.

Can you use perforated PVC pipe?

You can use either perforated PVC pipe or corrugated drainage pipe. While PVC has the advantage of being more durable and requires less slope than corrugated drainage pipe, it’s more expensive and is not flexible, making installation a bit more challenging and will likely drive up the cost of labor.

Can you put dirt on a French drain?

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. Instead, wrap the French drain and surrounding aggregate rock in a commercial grade permeable material like landscaping fabric.

Do you need to plan for drainage around your home?

Home builders should do their part to ensure that water flows away from your home’s foundation out into the yard. However, you may notice there are still areas of your yard where water tends to pool.

Can a French drain kill grass?

Allowing the water to remain in these areas can kill your grass, erode the soil and even cause foundation problems. Installing a French drain is one drainage solution that provides a path for pooling water to travel away from your property. Installing underground drainage pipes is not an easy job and can get costly if you need to hire ...

Is A French Drain Right For You?

Recommended Products

• If you do decide that a french drain is right for you, there are several options available in terms of product choices. You will need to select the type of gravel to fill the trench with and the type of piping to lay on top of the gravel. Here are some of the top products available. 1. Mexican Beach Pebble – This is product is an ideal choice for f...

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