There are numerous reasons why your driveway may be cracking. Cracking of asphalt or concrete can be caused by shrinkage, frost heave, settlement or from expansive tree roots as they grow out and away from nearby trees. If your driveway’s sub-base was prepared improperly, with the base being applied too thinly or inadequately compacted, the surface is more prone to settlement or frost heave. In areas that are prone to frost, concrete and asphalt surfaces must have a minimum of five inches of well-compacted gravel comprising the sub-base, below.
Concrete surfaces should have expansion and/or control joints. This prevents random cracking. A network of random cracks in concrete is an indication of a poor installation, a poor concrete mix, a lack of control joints or an improper sub-base. Asphalt can develop fine cracks as it ages. Some paving professionals recommend sealing asphalt every few years. Others discount the value of sealing. Heavy equipment or vehicles can also produce cracking in driveway surfaces.
An asphalt or concrete driveway that is exposed to harsh chemicals can be damaged. These chemicals can include automotive fluids and even ice-melting salts. Pavers, which are made of materials like stone, clay and concrete can flake off in freezing weather if they are unsuitable for use in the ground. For instance, if you are using clay brick pavers, they need to be very dense to resist the absorption of water. And the mortar you use can also crack when it freezes, so it’s important to perform periodic routine maintenance to keep it intact. Even pressure treated wood pavers will rot over time, which means that wood edging which is intended to hold pavers in place will also rot.
What to Look For
The worst problem with a cracking driveway is that it poses a tripping hazard for foot traffic, and this is a safety issue. Otherwise, cracks and damage are fairly cosmetic issues.
While it’s extremely difficult to notice conditions that could potentially lead to cracking and other damage in the future, there’s a lot you can do to check your paved surfaces for problem areas in the present. Look for things like missing edging, leaning support walls, wood that has begun to rot, the erosion of soil beside the area,, and the presence of small trees nearby that will grow quickly, and the larger they grow, the more difficult it will be to remove them. Their roots will definitely damage your driveway. Look for pavers that are beginning to spall or flake, and missing control joints.
Look for areas with the right conditions for water accumulation like low spots or where the downspout discharges. Pay attention to these areas to stay on top of any future changes.