Best Gravel for a French Drain

Yards with drain problems after heavy to moderate rains will benefit from a French drain. If you find your yard constantly flooded or underwater, this drain system can help keep the water away from your home and its foundation. You need to design it according to recommended specifications and use the best gravel for a French drain so you can reap its benefits.

What Is a French Drain?

A French drain is a drain system that prevents water pooling, allowing water to flow into the lower parts of your yard and then onto the street or other areas outside your property. Its primary design concept is relatively simple – you add a slightly sloped trenching area in your yard to keep the water away. This sloped trench will be installed in the areas of your yard that tend to pool water when it rains.

The trench will be sloped downwards away from your home and then lead to the street, where public drain systems can manage the excess water. This trench should be filled with the appropriate type of gravel that is well-suited for draining. Because of this critical detail, homeowners tend to ask which is the best gravel for a French drain.

French Drain Design Details

A French drain needs to have a sloped ditch to draw water away from a designated area (such as your home’s foundation). The end-to-end slope of this trench usually goes one to two percent for the best water draining capability.

The trench will be filled with a layer of gravel, which will be covered by a few inches of coarse sand. Some homeowners also cover the sand with sod, keeping everything out of sight. In addition, some contractors add drain pipes at the bottom of the trench setup, which ensures the entire drain system will last longer.

Choosing the Best Gravel for a French Drain

The gravel layer at the bottom of the trench fills it around ⅓ of the way if you use a perforated pipe. If you do not include a pipe in your setup, then fill the trench with gravel ⅔ of the way. This gravel layer will serve as the main waterway to prevent pooling in your yard.

The best gravel for a French drain is usually the bigger ones. They’re typically half an inch to one inch across. The bigger the gravel you use, the better the water can flow. Bigger gravel also prevents blockages and clogs. If you’re not incorporating a perforated pipe in your setup, it would be best to use 1 ½ inch gravel for better drainage.

Pea-sized gravel may look good, but they’re not suitable for drainage. Likewise, smaller-sized rocks don’t allow sufficient water flow. Finally, ensure that the gravel you’re using is the washed variant to prevent dust and debris from slowing water flow.

If you’re adding drain lines in your trench setup, it would be best to use half-inch to one-inch gravel. They fit drain lines better and are big enough to filter the water properly. With this type of design, many contractors will recommend using river pebbles. This type of rock will be difficult to erode, allowing the gravel to last around 20 years.

Big Tip: before you pile the gravel into the trench, inspect the stones first. If the gravel feels sandy, dusty and cracked as if it will break, then it probably will. On the other hand, river rocks are smooth to the touch, which are best suited for French drains.

Work With the Trusted Foundation Specialists in the DFW Metroplex

Call the experts in the DFW Metroplex if you’re having water pooling and drain problems in your yard. At HD Foundations, we have specialists who will inspect your yard and recommend the best-suited drain systems to protect your home’s foundation. Reach out to our consultants today by filling out this form and get a free quote.