About Our Drainage Systems
Good drainage in the landscape is critical for the health and vigor of lawns and plant materials as well for sanitary reasons. Excess water that is not percolated into the soil and taken up by plant materials must be eliminated. The most common way to remove excess water is a combination of proper grading leading to inlets of a sub-surface drainage system.
OUR RESIDENTIAL SUB-SURFACE DRAINAGE SYSTEMS CONSIST OF THE FOLLOWING ELEMENTS:
- 3″ or 4″ solid wall drain pipe installed with a minimum fall of 1%, or approximately 1/8″ of fall per linear foot of drain line.
- 4″ drain inlets installed on average every 12 feet as needed. Larger inlets and drain basins installed in areas of heavy standing water and severe low spots as necessary. 4″ drain inlets are sufficient for most projects. Most other companies will install maybe 3 or 4 drain inlets total in an average yard, often at distances of 20 to 30 feet or more apart from each other. We feel this is insufficient. Inlets placed 12 feet apart in all low areas provides superior drainage, eliminating stagnant water from the landscape.
- We install drains in ALL low areas of the landscape, including planters…not just lawns. Our proposal may include more linear feet of drain line than other companies proposals. This is because we calculate the amount of drain line and drain inlets necessary to pick up ALL low spots within your landscape, not just a few spots to cover the minimum drainage requirements. We also pick up all rain gutter downspouts coming off the roof. For this reason, our proposal may reflect a higher cost for your drainage system than other companies proposals. Please understand that from us you are getting a complete drainage system with no areas neglected. We will be happy to bid a more basic drainage system if our proposed system does not fit your budget or needs, however, be advised that basic systems may not be sufficient to provide proper drainage in all areas of your landscape.
- We install all drainage systems in a continuous loop around the house whenever possible. Unfortunately sub-surface drain lines occasionally become obstructed. A continuous loop around the property ensures that if part of the line becomes obstructed, water will still have another path to follow until the obstruction is removed.
- All drain lines are either hooked up to your existing drainage system or brought out to the street. We provide curb coring if necessary.
Heavy soils often require more than just above-ground drain basins, especially if the grade is fairly level. In this case it is necessary to install a French drain. Installing French drains typically involves digging a minimum 12 inch wide x 12 inch deep trench in the area of standing water, throughout the entire wet area. The native heavy soil is removed. The trench bottom and sides are then lined with a porous silt fabric with enough extra to also cover the top. A perforated pipe is laid on top of about 3 to 6 inches of 3/4″ diameter gravel aggregate. The pipe and the remainder of the open trench is covered with more gravel, then the silt fabric is closed around the gravel and pipe.
Most companies will wrap the pipe only with the fabric. We wrap the gravel around the pipe as it creates much more silt fabric surface area to prevent particles and soil from entering the gravel and the trench, thus ensuring many more years of clog prevention over just a wrapped pipe. Finally, approximately 3″ of sand is placed on top of the trench to create a planting root zone for the lawn or plant materials that are planted above the trench. The sand allows water to percolate into the ground and then into the French drain in an area where it once would not percolate. This type of system is what is typically installed behind larger retaining walls to reduce the pressure water creates when it builds up behind the wall.