All driveways need a certain amount of excavation and grading before laying the asphalt down. How much is the question.
2 things need to happen for a good, solid driveway:
#1) We want to make sure that the sub-grade is stable so that the driveway is built on a solid foundation. A driveway is only as good as the subgrade beneath it. Usually 4″-6″ of Class 2 base rock follows industry standards
#2 We want to make sure that the driveway grading is done so that the water drains and sheds water properly.
It’s vital that water runs away from the garage or home to avoid flooding so the driveway needs to be graded to ensure drainage away from the house or garage.
We also want to make sure water runs off of the asphalt and doesn’t pool or stand on the surface of the asphalt.
These two factors alone require that most driveways have grading done before laying down the asphalt.
Believe it or not, some contractors will put very little time into grading the driveway properly and in the end you may end up with a problematic driveway that lasts half as long as it should, or even worse… a driveway that causes water to flood your home.
If you have a long and winding driveway leading up to your home, should the driveway be graded and paved with a crown, or should it be graded flat?
Grading a driveway with a crown is not recommended for a long asphalt driveway. The problem with a crown is that when you drive on the driveway with your vehicle, the tires run on both sides of the crown, straddling the hump in the middle. This will cause the asphalt to push down and outward on both sides… pulling the asphalt away from the middle and cause cracks that are parallel with the driveway.
Obviously we want to minimize the cracking of our newly installed asphalt driveway as much as possible so grading the driveway and installing the asphalt flat, but also pitch it to one side or the other so that the water will drain off is the right way to grade a long driveway. It doesn’t have to be a drastic pitch, but only about a 1/4 inch to 1/2 of an inch on either side. This will result in less maintenance and a much longer lasting driveway!