How to Repair Blacktop Driveways
Fix Asphalt Water Damage with Elastomeric Patch and Apply Sealer
Aug 1, 2008
Blacktop driveways are not concrete driveways. Because of this, they endure the elements differently. At some point, the need arises for a blacktop repair job.
Blacktop, also known as asphalt, is a petroleum product. To be more precise, it's a mixture of small rock chips, sand, and asphalt cement. Responding to temperature changes, it softens in hot weather and hardens when cold. Like other physical materials, it expands and contracts with temperature changes.
Types of Blacktop Damage
Blacktop is very susceptible to salt damage (as is concrete that is less than a couple of years old). Because of this, it makes more sense to use sand or some other non-chemical product for traction when ice is present.
Basically, two types of asphalt damage can occur. First, and the most common, is cracking. This is just the nature of the beast and nothing can be done to prevent it.
Expansion and contraction can cause this, and if let go, it will get worse. Water damage in the form of ice in the winter really exacerbates the problem.
Secondly, damage shows up as sunken spots and holes. What can cause this? Well, if the builder skimped on the driveway's base (foundation), the support will be deficient. Properly laid, it should be 8 to 10 inches of crushed, well-compacted gravel on solid soil.
If it's not right, it won't support properly.
Repairing Asphalt Cracks
Most people have seen road crews patching cracks in blacktop roads – guys in reflective vests wandering along ladling out molten, black goo. This is precisely what the homeowner should do. Just use a high-quality elastomeric asphalt crack filler.
This product can be had at any home improvement store. Home Depot and Lowes come to mind. If the crack is very deep, pour in some coarse, dry sand. After applying it to the driveway cracks, let it settle. Settling occurs both from oozing down and from the evaporation of the water in the filler.
Finally, refill the crack.
Repairing Blacktop Holes
Repairing holes in blacktop surfaces is a bit more involved than cracks. First, the sunken, broken up asphalt should be removed. The edges of the excavation should be vertical, not slanted. These edges act as a retaining wall for the new fill.
How deep is the hole? If over two inches, break up the dug-up old asphalt and use it for a filler. If gravel must be added to bring the hole up to a one and a half to two inches in depth, only use gravel with sharp edges, never rounded.
Now, tamp the base down solidly. Any blunt wide instrument can be used for this, even a 4” X 4”. Next, fill the hole with asphalt patching material. Form it up in a convex fashion, about a quarter inch higher than the driveway plane at its peak.
Now use a steel tamp to compact the patching material and force it into the base.
Using a Driveway Sealer
No mistake about it, an asphalt driveway should be sealed to protect it. But don't jump the gun. No sealer should be applied to a new surface or a patch for a minimum of 30 days. The material need open-air curing as the hydrocarbons evaporate.
