When planning the installation of parking lot paving, some people forget the importance of proper drainage. If the driveway does not drain correctly, the risk of water penetrating the surface and destabilizing the base is increased. Furthermore, poor drainage can result in damage to landscaping or water entering an attached garage, pooling around a home’s foundation or leaking into a basement.
My Driveway Needs To Be Paved, Is Drainage A Concern
• Fall: Fall is a measurement of how much the elevation of a straight line rises or falls from end to end. It is expressed in terms of inches of change per foot. For example, if a driveway is 10 feet in length and the elevation is 5 feet above street level, the driveway has a fall of 0.5 inch per foot. The minimum acceptable fall to ensure proper drainage is 0.25 inch per foot. Thus, a 10-foot driveway should have an elevation that is at least 2.5 feet higher, a 20-foot driveway should rise by at least 5 feet and so on. A fall between 0.5 and 1.5 inches is typically preferable as it helps water drain more quickly.
• Edges: One side of the driveway should be lower than the other to facilitate drainage. Local building codes may specify the acceptable difference between the two edges, but the minimum is usually a 2-percent change and the maximum seldom exceeds 15 percent. To illustrate, suppose a driveway is 10 feet (120 inches) in width; 2 percent of 120 inches is 2.4 inches, while 15 percent equals 18 inches. It is important to remember that this change in edge heights occurs gradually across the entire width of the driveway, so at the lower rates, it is often difficult to detect visually.
If you have a downhill driveway, or if your driveway has already been installed without proper drainage, there are other methods that your asphalt contractor may be able to use. For example, it might be possible to install one or more drains or channels to improve the drainage.
Alpha Paving Industries offers a full line of asphalt paving and pavement maintenance services to customers in Central Texas, including the Austin metropolitan area. Whether you are installing a new driveway, need a parking lot re-striped, asphalt repair, our crews have the expertise to provide you with quality results at reasonable rates. You can request a quote by using our online form to send us your information, or you can call 512-677-9001 to speak with one of our friendly, knowledgeable staff members.
Alpha Paving Industries is the Austin Asphalt Paving Expert in Central Texas!
