Crack filling cleans and dries each crack, then fills it with a hot-applied rubberized sealant that bonds to the asphalt and stays flexible in the cold. It is meant for cracks up to about an inch wide. Wider cracks and spider-web alligator cracking need to be cut out and patched instead.
Why cracks matter so much here
Rochester averages about 102 inches of snow a year, with roughly 27 inches in January alone (National Weather Service normals for 1991 to 2020). That means months of plows, shovels, road salt, and water that melts in the afternoon and refreezes overnight. Each time water in a crack freezes, it expands and pushes the asphalt apart. Each thaw lets more water in. Over a few winters a hairline crack becomes a gap, then a broken edge, then a pothole. Sealing the crack stops that cycle where it starts.
What the sealant is
Professional crack sealant is a rubberized material made of asphalt resins and synthetic polymer rubber. It is melted in a heated kettle and poured hot. The manufacturer data for the product we cite gives the specifics:
Bottled cold-pour crack filler from a hardware store is easier to use, but it does not bond or flex the way hot-applied rubberized sealant does, which is why it tends to shrink or pop out after a winter.
How we fill cracks
- Clean the crackWeeds, dirt and loose asphalt come out. Wider cracks may be routed to create a clean channel.
- Dry it with hot airA hot compressed-air lance blows out the last of the dust and dries the crack so the sealant bonds.
- Pour hot sealantRubberized sealant goes in hot and fills the crack from the bottom up.
- Band the surfaceA thin band of sealant over the top of the crack seals the edges where water would otherwise get in.
What crack filling will not fix
- Cracks wider than about an inch. These are cut out and patched with hot mix.
- Alligator cracking. Spider-web cracking means the base has failed. Sealing it hides the symptom. See driveway repair.
- Sinking or heaving. Those are base problems, not crack problems.
When to do it
Late summer and fall are ideal: the cracks are open and dry, and the sealant is in place before the first freeze. Crack filling is also step one of every sealcoating job, because sealer is too thin to fill cracks on its own.
Common questions
How do you seal cracks in an asphalt driveway?
Each crack is cleaned out, dried with a hot compressed-air lance, and filled with hot-applied rubberized sealant that bonds to the asphalt and stays flexible in cold weather.
What size cracks can be filled?
Crack sealant is meant for cracks up to about 1 inch wide. Wider cracks are cut out and patched with hot-mix asphalt.
Is crack filling worth it?
It is the least expensive maintenance a driveway gets, and it addresses the main cause of potholes in a freeze-thaw climate: water getting under the asphalt.
Can you fill cracks in cold weather?
The sealant we cite requires the pavement and air above 40°F, and cracks must be dry. In Rochester that means spring through fall.
Should cracks be filled before sealcoating?
Yes, every time. Sealcoat is too thin to fill cracks, so they are filled first.
Related services
- Driveway Paving: New asphalt driveways built on a real base, graded to drain away from your house.
- Driveway Replacement: Tear-out and repave when cracking, sinking or crumbling is past repair.
- Driveway Sealing: Sealcoating that protects asphalt from water, salt and sun, applied in the right weather.
- Parking Lot Sealcoating: Commercial sealcoating done in sections so your lot stays open.