I am planning to set up my patio myself. Right now my backyard is just a dirt lot. I am planning to set my whole patio in paver stone with a retaining wall along the back end. I understand the basic of how to lay the paving block. I need on how to set up proper drainage. I am planning to have the patio slope to the side of the house where I will set up the drainage. This will take care of the water that will run off the top of the patio. Do I have to worry about the water that seep through the patio? Any help or suggestion is greatly appreciated.