The Nuances of Driveway Paving
Paving a driveway is more nuanced than simply slapping on some blacktop. Different materials have strengths and weaknesses based on their ability to resist heat, rain, and cold weather. A strong support layer is crucial for long-lasting pavement. SC Driveway Paving Charleston recommends installing a sub-base of 10 inches of stone in two lifts.
The subgrade is the foundation upon which your pavement structure will be built. The quality of your driveway’s subgrade determines how long the paving materials will last before they need to be replaced. It is a very important part of driveway construction, and they take it very seriously.
The soil quality used as a base for your pavement depends on its load-bearing capacity. Load-bearing capacity is affected by the moisture content and density of the soil. A soil’s bearing capacity can also be improved through compaction, which increases its strength and resistance to movement under imposed loads.
To make sure the subgrade can withstand the weight of the vehicles passing over it, we use a special material called an aggregate base. It is a layer of crushed rock or other suitable granular fill placed on the soil and compacted to form a solid, well-consolidated surface. An aggregate base is very important because it provides a smooth, stable surface that prevents your car’s tires from skidding on the soft soil underneath.
To get the best results from your new asphalt driveway, we recommend using a quality aggregate that does not contain silt or clay and passes a No. 100 sieve. Our preferred aggregate is regular runner-crush, which has the advantage over other types of gravel, such as minus-4 stone, because it is much smoother and easier to achieve a final grade with.
We always put a woven nylon geotextile membrane on top of the aggregate base before we install our asphalt concrete. It aims to prevent mixing soft and insufficient dirt with the runner-crush stone. Combining these two different materials is not good since the ground can contaminate the concrete and cause premature failure of the asphalt pavement.
The subgrade should have sufficient drainage to keep the soil from becoming saturated and losing its bearing capacity. Proper drainage is also essential in preventing excessive moisture accumulation, which can also be a source of frost damage to the pavement.
Asphalt, gravel, and paving stones are common driveway paving materials. Each has advantages and disadvantages, depending on the climate, driveway design, and budget. Gravel is relatively inexpensive and works well in warmer temperatures. It is easy to install and requires minimal maintenance. However, it can soften on hot days and erode in damp areas, which means ruts and holes will likely form over time.
Concrete is a more durable option that can withstand heavier loads than gravel and lasts longer. It is also an affordable option but can crack in cold weather. Unlike asphalt, concrete is non-porous and responds well to chemical or natural ice melt. It is also easier to plow and shovel, which reduces winter maintenance.
Alternatively, you can use brick pavers to create a stylish, elegant, durable, and cost-effective look. They are available in various colors and can be laid in interesting patterns. These paving stones can be made from natural stone, fired clay, or molded concrete in multiple sizes and shapes.
If you prefer a more traditional appearance, you can choose to install an oil and stone driveway. This method involves spraying a layer of heated oil onto the surface and then spreading a crushed stone over it. The gravel is then compacted using a roller for additional strength. This driveway paving material is popular in the Northeast, and it offers a happy medium between an asphalt surface and a poured concrete driveway.
Another paved option is permeable Paving, a newer technology that allows water to flow through the driveway and into the soil below it. This type of Paving is a great choice for homeowners who want to reduce their carbon footprint, and it can be installed over existing asphalt or concrete.
Lastly, you can opt for a stamped concrete driveway. This type of Paving provides the durability of concrete with pre-designed frames. It can be a good option for driveways with frequent use and heavy vehicles. It is important to remember that stamped concrete can be more expensive than other paving materials and may only be suitable for some homes.
While only sometimes possible, a driveway constructed from pavers is often designed to accommodate a slope. If a sloped surface is preferred, the paving design must ensure the stability and drainage of the paved area. The design must also consider the safety of the driving and walking surfaces.
Generally, a maximum surface slope of 5% is recommended. However, this is based on several factors, including soil conditions, separation to groundwater, sub-base compaction, pavement mix and installation, adjoining infrastructure, operation, and maintenance.
When building a driveway on a slope, it is critical that the grading of the soil and base is performed correctly to prevent shifting of the entire surface and damage to the subsurface materials. It is especially important if the driveway slope exceeds 12%-15%.
In the case of a steep driveway, a header beam cast in concrete is usually placed at the lowest point of the slope, which acts as a stable foundation for the subsoil and base materials. It can be built before the curb is poured to avoid damage from running dump trucks and compaction equipment during construction.
Once the header beam is in place, the subsoil and base are installed and compacted to at least 98 percent of the maximum standard Proctor density. A 1-inch layer of bedding sand is placed over the aggregate base and compressed using a vibratory plate compactor. Finally, a geotextile is placed over the sand to keep the sand from infiltrating the drainage mat.
After the sand and mat are in place, a herringbone pattern of pavers is typically laid over the surface. This type of pattern interlocks tightly and reduces the likelihood that the pavers will shift horizontally under the vehicles’ weight, braking and turning on the sloped surface. Depending on the slope, edge restraints may hold the pavers in place and prevent them from moving down the hill during driveway use. Finally, a drainage system of pipes, French drains, or dry wells is used to direct water away from the paved surface and away from the subsoil.
A well-designed driveway should have a drainage system that prevents water from pooling. It is important for new construction and as a retrofit for existing driveways. If left untreated, drainage problems can lead to cracking and damage to concrete and asphalt driveways.
The type of driveway material you choose also impacts drainage. Some materials are better suited for certain climates than others, so consult your local paving company about what is best for your area. For instance, some paving materials don’t hold up in cold regions because of freeze-thaw cycles and may need to be replaced more frequently.
Proper drainage for your driveway will ensure that water is directed away from the home and towards the street during rainy weather. It will help prevent standing water that can erode the driveway and cause costly repairs.
One way to direct water is by installing a channel drain. It is a trench that runs the length of the driveway and is covered by a metal grate to prevent blockage from debris and other items. Another option is a French drain. These gravel-filled trenches house perforated pipes that redirect water away from the driveway and hydrate the surrounding soil.
Another effective drainage solution is to install a permeable paver system for your driveway. These aesthetically pleasing pavers allow water to filter through them and soak into the ground below rather than run off into the street or flood your yard.
A properly graded and sloped driveway will also help with drainage. Typically, the driveway should increase in height by a few inches for every foot that it is long. It helps to promote the proper flow of water and discourages puddle formation that can contribute to mold, moss, and other unwanted vegetation.