Asphalt Grading and Repairs
Here's why Perfect Pitch is Essential in the Install or Repair of an Asphalt Driveway
As a layperson, you may assume that a smooth, even texture is the most important aspect of an asphalt driveway. Actually, the grade of the driveway is the most critical thing about it. Proper grading makes the difference between a driveway that diverts water properly and a driveway plagued with pooling water or that diverts water in a manner that floods your garage, lawn, and home's foundation.
Water Problems? Blame Bad Pitch.
When used in regard to asphalt, "pitch" is defined as the degree of downward slope figured into the grade. It's essential that a driveway's pitch diverts water to the street and, preferably, to different parts of the street. Usually, a pitch of just 2% effectively redistributes water runoff. Anything exceeding 15% isn't advisable, as that creates a steep driveway that can be difficult to maneuver and dangerous in wet or icy conditions. The pitch of the area closes to the garage shouldn't exceed 2%, as this is where people typically walk.
The Results of Bad Pitch and Water Pooling
The consequences of insufficient grading and pitch when installing an asphalt driveway are significant and can range in seriousness from nuisances to safety hazards. They include:
- Alligator Cracks. These small cracks derive their name from the fact that they resemble an alligator's scales. They're more of an aesthetic problem than a safety issue, but without repair, they can lead to more extensive damage.
- Potholes. Alligator cracks left unrepaired can become potholes (large hunks of broken asphalt that can damage vehicle tires and alignment.)
- Sink Holes. Over time, standing water can causes the ground under asphalt to settle to such a degree that it “sinks” below the optimal grade of the driveway.
Calculating Perfect Pitch
The pros at RS asphalt calculate pitch using a rule of 1.5 inches per 10 feet of driveway. To achieve the ideal pitch, the floor of the garage must be 15 inches higher or more than the roadway. Another way to ensure desired water runoff is to skew the driveway pitch very slightly (¼ to ½ inch) to one side, so water runs off to one side of the driveway (similar to the way water collects in the rain gutters of a roof and runs off one side of the house.) The benefit of this second approach is that we can design the driveway pitch so water is directed to the lawn or a flower bed.
Whether you want to ensure your new asphalt driveway remains problem free, or want to repair problems caused by improper pitch and grade, call us at RS asphalt.