Quck answer
A French drain is a simple and effective solution for addressing water drainage issues in your yard. To install a French drain, follow these steps:
1. Determine the location: Identify the area in your yard where water accumulates or causes problems.
2. Dig the trench: Dig a trench along the perimeter of the problem area. The trench should be about 6-12 inches wide and deep enough to accommodate the drain pipe.
3. Add gravel: Line the bottom of the trench with a layer of gravel to create a stable base for the drain pipe.
4. Install the drain pipe: Place the perforated drain pipe on top of the gravel, ensuring that the holes face downwards. Connect the pipe sections as needed.
5. Cover the pipe: Add another layer of gravel or a permeable landscape fabric to cover the drain pipe.
6. Backfill the trench: Fill the trench with soil, making sure it is compacted to prevent settling.
7. Test the drain: Run water through the drain to ensure it is working properly and redirecting water away from the problem area.
By following these steps, you can successfully install a French drain in your yard and effectively manage water drainage.
If you’re experiencing problems with water pooling in your yard, seepage into your basement, or excessive runoff from patios, walkways, and driveways, installing a French drain could be the solution you need. Named after its inventor, Henry French, a Massachusetts native who came up with the idea in the mid-1800s, this system involves digging a gravel-filled trench with a slight slope toward a catchment point. Perforated drain pipe covered in landscape fabric is placed in the trench to prevent clogging. French drains have been a popular landscaping staple in North America since French’s book, Farm Drainage, was published in 1859.
The concept of a French drain is simple and can be installed by any homeowner with a shovel. For more complex systems, such as those used around foundations or in basements, professional installation may be required. However, a basic yard drainage system is a straightforward DIY project.
How French Drains Solve Common Drainage Problems
In an ideal world, properties are graded away from houses with gentle slopes that allow rainwater to seep into well-draining ground. However, this is not always the case. French drains can improve drainage in situations such as poorly draining soil, low spots, abrupt changes in slope or man-made obstructions causing streams, and high water tables or springs. They collect water at ground level and direct it to a suitable place, such as a natural catchment or runoff point. In some cases, a dry well on the property can be used if no natural runoff point exists or if directing water to a municipal drainage network is impractical or illegal.
French drains can also resolve foundation and basement drainage problems. Footing drains catch water that would otherwise seep through foundation walls, and channel drains covered by drain tile in the basement floor direct excess water to a central point where a sump pump can transfer it outside. Professional contractors are usually required for these installations due to the amount of digging involved, and costs can range from $50 to $100 per linear foot.
Image Credit:
JeanCuomo/iStock/GettyImages
How French Drains Work
A French drain is most useful in low-lying areas with standing water or soggy soil that remain that way for days after heavy rain. These areas may have clay-like soil or receive water from higher elevation areas. French drains can also be effective at the edges of impermeable surfaces, such as concrete patios or asphalt driveways, where runoff is heavy and water pools.
A French drain is able to absorb water from both surface and deep in the ground due to its permeability. The water flows towards the slope of the trench, which needs to be at least 1 inch for every 8 feet according to Mr. Rooter. A gentle slope allows some water to seep through the perforated drain pipe and return to the water table by sinking into the soil.
When designing a French drain system, it is best to install it on ground that slopes downward to keep the trench depth uniform. If it cannot be avoided to install it on flat ground or ground that slopes in the opposite direction, extra depth needs to be planned for at the end. The exit of the drain should be on a grassy slope with good sun exposure or on the street if allowed. Never direct water onto a neighboring property or anywhere that could cause erosion or cover sidewalks and public roads with water that could turn into ice. If there is no suitable natural runoff point, the drain can be terminated in a dry well. Check with the local planning office for permit requirements and regulations if draining water onto the street.
To install a French drain, start by locating underground utilities with the help of 811. Wait for all lines to be marked before starting the installation process. The things needed include wooden stakes, string, landscaping fabric, angled drain rock, perforated drain pipe, line level, tape measure, spade, round shovel, tarp, and a trencher (optional).
Step 2: Mark the Drain Path and Measure Ground Slope
Place stakes along the drain path and calculate the elevation change between each pair of stakes. Tie a string to the stake closest to the start of the drain and use a line level to center the bubble. Measure the distance from the string to the bottom of the stake, divide by the distance between stakes, and multiply by 100. If the result is less than 1 percent, dig the trench deeper at the lower end. If the ground slopes upward, adjust the string to determine how much deeper the trench needs to be at the opposite end. Be careful to avoid tree roots and woody shrubs when marking the drain path.
Step 3: Excavate the Trench
Cut the turf on both sides of the trench with a spade and dig the trench with a round shovel or trencher. The trench should be at least 12 inches wide and deep enough to hold gravel and a perforated pipe. Deposit the dirt on a tarp to make it easier to remove. The beginning of the trench should be deep enough for 8 to 12 inches of gravel, a perforated pipe, and topsoil. The other end should be just as deep plus extra depth for the trench slope.
Step 4: Use Filter Fabric to Line the Trench
Place filter fabric along the trench to prevent debris from clogging the surrounding soil. The fabric should extend 12 inches from the top of the trench on both sides.
Step 5: Add Gravel to the Trench Bottom
Fill the trench with 2 to 3 inches of angled drain rock. Use an online gravel calculator to determine how much gravel is needed for the project.
Step 6: Install Perforated Drain Pipe
For this step, you have the option of using either 3- or 4-inch corrugated drain pipe with slits or PVC pipe with holes. While corrugated drain pipe is easier to handle, it clogs more easily than smooth PVC pipe. If you opt for PVC, it’s ideal for a long trench since you can install tees and risers that make it easier to clean the pipes. Remember to install the pipe with the holes facing downwards.
Step 7: Fill With Gravel
Make sure to cover the pipe with gravel until it reaches 2-3 inches below the top of the trench. Once done, fold the landscape fabric over the pipe and gravel, ensuring it’s completely enclosed. Many landscapers suggest folding the fabric over the pipe before filling with gravel to hold it down and prevent it from being visible in case the topsoil washes away.
Step 8: Cover the Trench With Soil
After covering the gravel, use some of the soil you removed from the trench to cover it. If you plan on replacing the old turf or starting with a new sod, make sure to leave enough space. Otherwise, backfill it to ground level and reseed it with grass seed.
FAQ
1. What is a French drain and why would I need one in my yard?
A French drain is a type of drainage system that is designed to redirect water away from an area, such as your yard. It consists of a trench filled with gravel or rock, with a perforated pipe placed at the bottom. The purpose of a French drain is to prevent water from pooling in your yard, which can cause flooding, erosion, and damage to your property.
2. How do I determine where to install a French drain in my yard?
The location of your French drain will depend on the specific drainage issues you are experiencing in your yard. Look for areas where water tends to pool or where you notice excess moisture. You can also consider the slope of your yard and areas where water naturally flows. These are typically good locations to install a French drain to redirect the water away from your yard.
3. What materials do I need to install a French drain?
To install a French drain, you will need a few materials including a shovel for digging the trench, a perforated pipe, gravel or rock to fill the trench, landscape fabric to prevent soil from clogging the system, and a level to ensure proper slope for water flow. Additionally, you may need connectors and fittings for the pipe, depending on the length and layout of your French drain system.
4. Can I install a French drain myself or do I need to hire a professional?
Installing a French drain can be a DIY project if you have basic knowledge of landscaping and plumbing. However, it can be labor-intensive and require some digging, so it’s important to consider your own abilities and the size of the project. If you’re not confident in your skills or if the project is complex, it may be best to hire a professional to ensure the French drain is installed correctly and effectively.
5. How do I maintain a French drain once it’s installed in my yard?
Maintaining a French drain is relatively easy. Regularly check the drain for any debris or blockages and remove them if necessary. Inspect the surrounding area for any signs of erosion or pooling water, as this may indicate a problem with the drain. If you notice any issues, such as a clogged pipe or damage to the system, it’s best to address them promptly to prevent further damage to your yard.