Why parking lots crack
Several forces work on asphalt at the same time:
- Heat and UV: sun oxidizes the asphalt binder, making the surface stiffer and more brittle over time.
- Thermal movement: pavement expands in heat and contracts in cold, which opens transverse and block cracks.
- Freeze-thaw: water in cracks freezes, expands and pries the crack wider, then lets more water in at the next thaw.
- Traffic and base problems: repeated loads on weak or wet base produce fatigue (alligator) cracking.
Which cracks can be sealed
Crack sealing is designed for individual linear cracks — longitudinal, transverse and block cracking — on pavement that is otherwise sound. Working cracks that open and close with temperature benefit most from a flexible hot-applied sealant.
Alligator cracking is different. It signals the pavement structure is failing under load, and sealing it does not restore support. Those areas usually need patching or base repair. Very wide cracks may need filling or patching rather than standard sealing.
How crack sealing is done
A durable crack sealing job is mostly preparation:
- Clean the crack of debris and vegetation, typically with compressed air or heat.
- Rout cracks where the scope calls for it to create a reservoir for sealant.
- Make sure the crack is dry.
- Apply hot sealant to the specified profile so it can flex with temperature.
- Allow the sealant to set before traffic returns.
Timing and weather
Crack sealing is commonly done in moderate temperatures, when cracks are partly open — spring and fall are typical. It can often extend later into the season than sealcoating because it does not need the same long warm cure, but it still needs a dry crack and suitable conditions. Any late-season scheduling is weather-qualified.
What drives crack sealing cost
Crack sealing is priced mainly by the linear feet of cracking, crack width, whether routing is included, and how accessible the lot is during the work. Every number depends on scope, thickness, access and season, so we price from a site review rather than a formula. It is typically the lowest-cost maintenance step per area of pavement protected.
Signs your lot needs crack sealing now
Some warning signs mean water is already reaching the base. Watch for these, especially after the first freeze-thaw cycles of the season:
- Cracks wide enough to see grass or weeds growing in them.
- Cracks that look darker or stay wet after the rest of the surface dries.
- Edges of cracks starting to break or crumble.
- New cracks branching off older ones.
- Small depressions or potholes forming along existing cracks.
How often to crack seal
New cracks keep forming as pavement ages, so crack sealing is a recurring task rather than a one-time fix. Many owners have the lot reviewed each year or two and seal new cracks as they appear, which keeps each round small and keeps water out of the base continuously. Previously sealed cracks are checked as well; sealant can debond or wear and may need attention. Pairing crack sealing with a sealcoat cycle is a common, efficient rhythm for commercial lots. Keeping a simple record of when and where cracks were sealed also helps you compare bids and spot areas that keep failing, which can point to a drainage or base problem worth investigating.
Crack sealing before sealcoat and overlay
Cracks should be sealed before a lot is sealcoated, otherwise the coating bridges over them and they reappear quickly. Before a mill-and-overlay, crack treatment and repair of the existing surface reduce how much old cracking reflects through. See commercial sealcoating and the parking lot repair comparison for how crack sealing fits into the larger plan.
