A French drain is a trench filled with gravel or types of pipe that divert water. French drains are the easiest option for homeowners trying to divert water away from an area of their yard or away from their home's foundation or basement. A variety of problems and issues can arise during the installation process.
Hard, compacted ground makes digging the narrow and deep trench required for a French drain difficult. Soil with a high clay content compacts tightly, especially if the area you are digging is regularly wet. The experts at Building Scoop say that the digging process is the most labour intensive part of the installation process. Picks and post hole diggers are used to break up hard soil, and homeowners will need a quality shovel or spade for the job. Making the trench wider, from the usual 6 inches to 8 or 12 inches also makes the process easier.
Damaged Pipes and Cables
One improperly aimed strike from a heavy shovel can burst water pipes, gas lines and cables running to the home, which leads to interrupted service and a possible fine as well as the danger to the digger. The Easy Digging website recommends calling your utility companies a week or more before you plan to begin installing French drains. The company will send an employee out to scout the locations of any underground pipes and cables and will mark them with small flags.
If you point the drain towards your home's basement or foundation, or run it along the wall, the water may leak into the structure if it is not properly sealed. Industrious homeowners may want to seal the foundation with a Portland cement-based sealant as they dig around the structure, especially if leaks are already common. The experts at HGTVPro also recommend designing the trench to run to a sufficient depth to release water underneath the foundation or basement.
Badly Designed Drainage
A French drain relies on gravity to pull water through the trench, which means that it must feature a specific amount of slope. The experts at Grounds Maintenance recommend a 1 to 2 per cent slope for the best results. Anything less than this, and the drain will fill with water and overflow. You must also take care when digging the trench to prevent bumps from setting any pipes on an incline.