Patios are constructed with a variety of materials such as concrete, stone pavers and wood. Regardless of the material, water that pools around the patio can lead to structural damage. Not only can the water compromise the structure, it can be a health hazard, a breeding ground for mosquitoes. A do-it-yourself solution is to install a French drain -- a perforated, corrugated pipe placed in a trench below the ground -- to transport the water to another location.
Drain Path and Trench
The French drain should run from the patio area, where the water pools, to a lower spot on your property. Use stakes to indicate the drain's path. Dig a channel or trench to a depth of about 18 to 24 inches and depending on the size of the drainage pipe, 6 to 12 inches wide. For the water to drain away from the patio, the trench must maintain a slope of 1 inch for every 8 feet.
A 2-inch layer of crushed stone or pea gravel sits at the bottom of the trench. Cover the gravel with landscaping fabric positioned so the excess fabric runs up the sides of the trench. Place a corrugated drainage pipe in the trench with the holes facing the bottom. Wrap the fabric around the pipe and pour a blanket of gravel into the trench to about 3 inches below the ground's surface. Top off the trench with dirt and turf.