French drains re-route excess water away from homes and other structures, safeguarding foundations, preventing flooding and improving landscape health. They require excavation, gravel and drainage pipe to be successfully installed.
If you have experience with landscaping and basic construction, a French drain installation is a manageable DIY project. However, more complex projects involving buried utility lines may require professional help.
Pipe
A French drain is a series of perforated pipes funneling excess water away from problem areas. This helps protect foundations, basements and yards from damage caused by flooding, standing water or soil compaction. It also prevents soil from becoming eroded and unusable over time. The French drain installation in New Jersey is relatively simple, but there are several steps to follow for a successful project.
Call 811 before starting any work in your yard or garden is important. This will allow your local utility company to mark all underground cables and pipes before you dig. Next, identify where you want to install the drain. Ideally, the drainage system should run from a higher to a lower elevation to promote proper flow. If you need help finding the best location for your French drain, consider using landscape design software or hiring a professional to determine where and how the system should be placed.
Once the trench has been dug, landscaping fabric should be laid over the entire area to protect the pipe. It should be a water-permeable fabric that will keep soil and small debris from being washed into the holes of the drain pipes. You can also use a specialized drain pipe with a built-in fabric “sock” to reduce the likelihood of clogging.
On top of the landscaping fabric, layer in a layer of gravel or rocks. The gravel size can vary, but you must ensure it is large enough to provide a good flow rate through the French drain.
Weed Barrier
Before beginning the trench for your French drain, call 811 to have all underground pipes and lines marked. Once the bar has been drawn, dig a path that slopes away from the problem area (like your home’s foundation or basement) and into an existing drainage ditch or natural water runoff point. This encourages surface water to flow downhill rather than pooling at your home’s foundation or in your yard.
After digging, line the bottom of the trench with a weed barrier or a water-permeable landscape fabric mesh. This will stop soil and contaminants from getting into your drain pipe and potentially clogging it.
Woven weed barriers are made with a weaving process that interlocks yarns or fibers in a crisscross pattern, creating small uniform openings that allow for air and water to pass through but block the growth of weeds. Non-woven fabrics use a similar process by bonding fibers together without weaving, making them lighter and stronger than woven varieties.
Instead of landscape fabric, you can cover the bottom of your French drain trench with a thick layer of organic mulch like compost or shredded bark. This prevents weeds and improves the health of your soil by allowing earthworms to reach the surface and break down organic material that feeds the ground.
Gravel
A French drain is a series of perforated pipes that funnels water away from foundations, basements, and your yard. Your French drain must be properly maintained to ensure functioning as intended and not clog with soil, roots, and other debris.
You’ll need to dig a trench big enough for the drain pipe. The trench must have a slight slope to allow for proper drainage. To calculate the appropriate grade, drive stakes at the top and bottom of the desired drain location. Tie a string between the stakes and use a carpenter’s level to measure the difference in height between them.
Once the trench is excavated, a gravel layer must be placed. It’s best to use a larger rock for this layer to help with the drainage, and it can be topped with smaller rocks for a more decorative look. Landscaping fabric is also placed atop the gravel, and it will keep soil, roots, and other small debris from clogging up the pipe.
Some people choose to plant their French drain, which can add a beautiful accent to your landscape while keeping water flowing to where it should be. Plants like wildflowers and grasses that can withstand wet soil conditions are great choices for this purpose.
Filter Fabric
Heavy rains can lead to flooded yards, damage grass, and even threaten your home’s foundation. A French drain prevents these issues by directing water flow away from your property.
The process begins with a trench, which should be dug at a slight slope, ideally towards a drain outlet such as a municipal storm drain or dry well. The trench should be 3 feet from fences/walls, posts, and tree roots to ensure proper drainage.
Before you dig, contact your local government’s “Call Before You Dig” hotline to find out the status of underground utilities. This will let you know if you need to call the utility company to have any lines marked before starting your French drain project.
Once the trench is dug, a landscaping filter fabric should be placed over it and encased with gravel. This will keep soil, roots, and debris from clogging the pipe, making your drain less effective. The landscaping fabric also protects the ground from damage during the installation process.
Use a woven geotextile drain fabric suitable for French drains for the best results. This type of fabric is stronger than non-woven varieties and can handle the strain of large rocks and other materials that might be encountered during installation. Also, choose the right drainage rock to maximize permeability and ensure good flow. Ideally, you should use clean natural 1-1/2″ round stone, better at enabling proper drainage than pea gravel.
