Driveway Paving Basics

Driveway Paving Charleston SC is one of the most important decisions you can make for your home. The right driveway balances design and utility.

Driveway Paving

Gravel is an inexpensive, easy-to-install paving option. But, it migrates and spreads under the weight of vehicles and needs borders or stabilizing pavers.

Concrete is more expensive, but is considered a cost-effective choice over time. It’s also one of the most durable options.

As the name suggests, the subgrade is the foundation of your driveway. It must be free of vegetation and well compacted. Since a new pavement is such a heavy load, it’s important that the subgrade has enough support to prevent sinking and settling over time. It’s also a good idea to lay down a base course over the subgrade, especially if your soil is soft or has limited load-supporting capacity.

The sub-base is typically made of unbound granular material and goes underneath the layer of asphalt you’ve chosen for your driveway. It acts as the primary load-bearer, spreading the weight of the paving surface evenly across the ground beneath it. The material is usually crushed stone or gravel, but may be cement-bound in some cases.

In addition to being a strong load-bearer, the sub-base also helps improve drainage and stability. A properly prepared subgrade will drain water away from the area, preventing standing water and erosion. It’s important to make sure the sub-base is a proper thickness, too. To do this, it’s often compacted using heavy machinery. This ensures the material is dense and ready to support the weight of the paved surface.

If you’re building a new driveway over existing pavement, it’s important to remove all old materials from the site before starting construction. This includes the concrete, which can be very hard and heavy. It’s also necessary to grade the surface, leveling it and providing the proper slope for drainage. Ideally, the slope should be toward the street and away from structures like your house or garage.

It’s a good idea to start your driveway project in the spring or fall, when the weather is dry. Avoid summer if possible, as the humidity and heat can cause the ground to become too saturated to be worked.

If you’re building a new asphalt driveway over an existing concrete one, it’s important to dig out any soft spots in the existing subgrade and replace them with a proper mixture of rock and aggregate. This will help the new pavement last longer and provide a smoother, more even ride for you and your guests.


Asphalt is one of the most commonly used pavement materials for driveways, roads and parking lots. Yet many people have no idea what it’s made of, or how manufacturers make the mixture that they drive on every day. In fact, it may surprise you to learn that asphalt is actually a much more complicated substance than concrete, with a variety of different mixes and production processes.

An asphalt paving contractor will decide what type of mix is needed for your project, based on the expected amount of load from vehicles on the pavement surface. For example, a large distribution center that expects heavy trucks to be loading and unloading daily will require an asphalt mix with higher shear strengths than that needed for a suburban driveway.

The asphalt mix is composed of aggregates (crushed rock, sand, gravel and/or slags) and a binder. The most common binder is bitumen, but there are also bio-binders that are now available to increase the sustainability of asphalt. The aggregates are mixed with the bitumen or bio-binder in an asphalt mixing plant to form a cohesive mixture. The temperature of the mixture is controlled during the mixing process to ensure that it reaches its desired viscoelastic range.

Once the asphalt mixture is formed, it is stored in heated storage silos until it is ready to be transported to the construction site. Depending on the needs of the job, additional ingredients or additives may be added to the asphalt mixture to achieve specific properties or performance characteristics.

For instance, adding 1.7 percent phosphoric acid will stiffen the asphalt, while 19 percent recycled oil base (REOB) will soften it. The additives are added to the asphalt while it is still in a hot state, so they can effectively spread and compact into place by the roller machine that will be using it on the driveway.

Cold-mix asphalt is a variation of asphalt that is used when the weather is too cold to use hot-mix. It isn’t as strong as hot-mix, but it can be used to patch areas that don’t get much traffic and are only temporary until the weather warms up.


Drainage is the key to a long-lasting and functional driveway. When a paved surface doesn’t drain correctly, it can cause serious problems. The standing water slowly eats away at the base that supports the driveway, and this can lead to structural damage. Not only is this problematic for the driveway itself, but it can also affect the foundation of structures like garages, which are often built right next to the driveway. Foundation issues can be very costly to repair and are typically not something that you want to leave up to chance.

There are several different ways to ensure proper drainage in a driveway. One option is to use French drains, which are long drain pipes that run the length of the driveway and have a grate on top to prevent debris from clogging the system. Another option is to use channel or trench drains, which are much like French drains but can be installed across a larger area of the driveway. These are also covered by a grate to prevent debris from clogging the system.

Swales and dry wells are also effective solutions for drainage. These are usually shallow ditches that can be filled with rocks or vegetation, and they work to slow down the water flow and redirect it to a lower area of the property. This helps to prevent erosion, and it can also help to eliminate auto pollutants that would otherwise wash into our aquifers and rivers.

Depending on your home and landscaping, you may even consider using permeable pavements to manage drainage in your driveway. These are paving materials that allow water to pass through the openings or voids in the paving material and return to the soil below. This considerably reduces the amount of runoff that can potentially cause flooding and other problems.

Whatever drainage solution you choose, it is best to have it installed by an experienced professional to avoid any potential complications down the road. You don’t want to have to replace your driveway, and you certainly don’t want to be stuck with foundation repairs for a damaged or discolored section caused by standing water.

Seal Coating

Seal coating is the final step in the driveway paving process. It creates a protective layer that shields the asphalt from the sun’s oxidation, and chemicals that eat away at the surface of the pavement. It also helps fill in minor cracks and adds a nice deep black finish to the pavement. When applied per the manufacturer’s instructions, a regularly scheduled sealcoating program can more than double your asphalt’s lifespan.

Prior to seal coating, the pavement should be blown or swept clean of any debris and dirt that’s accumulated on the surface. This is especially important if your driveway or parking lot is used by commercial vehicles that tend to leak oil, gas, and other contaminants that can wreak havoc on the surface of the asphalt.

Before applying the sealant, make sure that any minor repairs are filled and that any existing potholes are patched. Also, be sure to tape off any areas that shouldn’t be sealed (like the edges of paver steps or a garage door). Then mix the sealant according to the manufacturer’s instructions. Depending on the size of your driveway, you may be better off using a roller or squeegee to apply the sealant rather than brushing it. It’s best to apply the sealant in a uniform direction and to move slowly so that you can get an even coat.

Once the sealant dries, it provides a smooth surface that makes your driveway or parking lot easy to sweep clean. It also prevents the leaking of oils, gasoline, and other chemicals into small cracks that can eat away at the surface of your asphalt pavement. A smooth surface is also easier to drive on, and it reduces the amount of wear and tear on your vehicle’s tires and axles.