Sub-soils are native soils found on your site. It could be top soil, clay base, or gravelly in consistency. Depending on the sub-soils on your site, whether your ground is soft, wet, moves when driven on, has rock larger than twelve inches, or has organic soils such as (grass, weeds, tree roots), these sub-soils should be removed to make room for proper sub-base.
Sub-base is the foundation that supports the load of the pavement and whatever drives on it. Due to harsh winters, spring thaws, heaving, daily use, or heavy delivery vehicles sub-base is important. A proper sub-base consists of various sizes of crushed stone aggregate, commonly known as crusher run. There are 3 commonly used types of stone aggregate. Depending on the sub-soils on your site you may need 8-12 inches of various sizes of sub-base. With well drained sub-soils, without movement, added sub-base materials may be sufficeint, along with proper pitch & grade. If your sub-base is knowingly sufficient, grading & compaction with vibratory roller or plate compactor in small areas, may be all that is necessary.
Stabilization fabric is a woven fabric placed down after excavating the sub-soils. This keeps your sub-base separated from your sub-soils. The fabric is commonly used on wet or clay based sub-soils. Using stabilization fabric can increase the life-span of your driveway. We can guide you if this is required on your project.
Grading is important because it eliminates pockets, high spots, and uneven areas in your sub-base. By grading your sub-base we can create room for asphalt materials by, garages, walkways, and the road. Grading is also used to set the proper slope and pitch for drainage. With this achieved compaction of the sub-base is important. With out compaction any pockets, high spots, or uneven areas will repeat into the pavement. This will leave you with a sub-standard driveway.
Slope and pitch is the fall you want away from your home, garage, and yard. You do not want ponding of water, or water to run towards your home or garage. Depending on your property, we may need to do extra work to achieve this. As a rule of thumb, you want your driveway to slope 2.5 inches every 10 feet. This provides proper drainage to make a longer lasting driveway, without having to deal with water problems.
There are two main courses of pavement that make up a paved driveway, binder course and top armor course or finish coat. The first coat to be placed, on top of your proper sub-base, is the binder course. The binder consists of a heavier stone and asphalt mixture. This coat is put in place for strength , plus it works as a true-leveler course, to take out any small imperfections in the grade. After the binder is put into place with paver (where possible, or by hand where paver cannot fit), it is compacted with a vibratory roller. The roller compacts the asphalt for tighter density and added strength. The second course is the top armor course or finish course. The finish coat consists of a finer stone and asphalt mixture. The finish coat is designed to make the top smoother and tighter, to keep water out. This will make the driveway more eye appealing, easier to clean, and a better wear surface. This course is placed on top of the binder course, after the binder course is compacted and has time to set up. A single layer of finish coat can be placed without the binder coat , for light duty use, saving a little cost to your project, but remember the binder course is where the strength is and a true leveler course. When rolled some small imperfection maybe left that the finish course takes out.
Yes you can resurface your current pavement. Depending on some conditions. Such as do you have proper pitch and clearance to add near garage doors and walkways. Any rocks popping up should be removed and patched back in. Then if needed a shim coat (thin coat of pavement to true-level current pavement) can be placed. This eliminates any pockets, ups or downs in current pavement. Then a constant depth of finish coat of 1½ - 2 inches of thickness. We can advise you if a resurfaced driveway can be done. In some cases if current pavement does not have proper sub-base , it would be better to correct this issue, because this may be why the current pavement has failed, not due to age.
Before we do any paving we make sure all proper specifications are addressed, such as sub-soils, stabilization fabric, sub-base, and slope and pitch. When all specifications are correct we then go ahead and put down two courses of blacktop. Every project we do is different, we can help you by informing you of what specifications you already have and what ones you need.