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TroubleshootingParking Lot Maintenance

Why is my parking lot asphalt cracking?

Most parking lot cracks come from age and weather: asphalt hardens and shrinks, and daily heating and cooling splits it into lines and blocks. Small, many-sided pieces in the wheel paths are different. That is fatigue from repeated traffic, usually over a weak base, and needs repair, not sealer.

Free to ask. Local shops send quotes, and you pay only when you book one.

By Kasra Taheri, Founder, LoclisPublished

Researched and drafted with AI, then checked claim by claim against the sources listed below before it was published. Prices and rules change; the dates beside each source say when it was last checked.

Step by step

Read when to stop and call a pro, further down this page, before you start.

  1. Step 1: Sketch the lot

    Draw a rough plan of the lot and mark the drive lanes, entrances, dumpster pad and loading areas, so every crack you find can be placed on it.

  2. Step 2: Name the pattern

    Note whether each crack is a single line, a large rectangle or a cluster of small many-sided pieces, and whether it follows the wheel paths.[1]

  3. Step 3: Measure the widest cracks

    Measure a few cracks with a ruler; federal highway inspectors rate block cracks of a quarter inch or less as low severity and over three quarters of an inch as high.[2]

  4. Step 4: Walk the edges

    Look along the edges beside lawn, gravel or landscaping for crescent-shaped cracks and crumbling.[2]

  5. Step 5: Watch the water

    After a rain, mark puddles that stay in the same low spots and any place where runoff enters the lot from a slope or downspout.[1]

  6. Step 6: Photograph and date it

    Take dated photos of each problem area with a coin or ruler for scale, so you can compare next season and show a bidder.

  7. Step 7: Fill the narrow cracks

    Clean out cracks up to half an inch wide and fill them with an asphalt crack filler before any sealing.[3]

  8. Step 8: Get the rest assessed

    Have a licensed paving contractor look at clusters of small pieces, sunken areas, bulges and wide cracks before you spend money on sealer.

The short version: age cracks and load cracks are different problems

Most cracks in a parking lot come from age and weather. Asphalt hardens and shrinks over the years, and daily heating and cooling splits it. A cluster of small, many-sided pieces in the wheel paths is a different problem: the lot is failing under traffic, usually because of what is underneath. The first can be sealed and maintained. The second needs repair.

Cracks from age and weather

Block cracking is caused mainly by shrinkage of the asphalt and daily temperature cycling, it is not load associated, and it usually means the asphalt has hardened significantly.[1] It looks like a grid of rectangles, in blocks from roughly 1 by 1 foot up to 10 by 10 feet.[1]

Single lines running along or across the pavement have a similar cause. Longitudinal and transverse cracks can come from a poorly built paving joint, from shrinkage of the asphalt in low temperatures or as it hardens, or from cracks in a layer underneath reflecting up through the surface;[1] these cracks are not usually load associated.[1] A related sign is the wearing away of the asphalt binder and fine aggregate from the surface, often with fading of the asphalt colour.[1] That is surface weathering, and it means the surface is aging.

A worker in a white coverall and hard hat driving a red pavement sealing machine across an asphalt lot, with fresh black sealer on the surface to the left and painted stall lines at the right
Photo: NAVFAC, CC BY 2.0, via Wikimedia Commons

Cracks from traffic and the base

Alligator or fatigue cracking is a series of interconnecting cracks caused by fatigue failure of the asphalt surface under repeated traffic loading.[1] It starts at the bottom of the asphalt, where the strain under a wheel is highest, and works up to the surface as parallel cracks that later join into sharp-angled pieces.[1] The giveaway is location: it shows up only where wheels pass repeatedly.[2][1] In a lot, look at entrance drives, the lanes delivery and trash trucks use, and the turns in front of a loading dock.

The Texas Department of Transportation's maintenance manual says alligator cracking is generally caused by inadequate base support or a brittle asphalt surface, and that where the base is unstable or wet, the base has to be removed and replaced or stabilized.[5] Filling the cracks does not fix a weak base, and sealer over them will not hold it together.

Edges, sunken spots and bulges

Look along the edges. Edge cracking is crescent-shaped or fairly continuous cracks within 0.6 m (about 2 feet) of a pavement edge beside an unpaved shoulder.[2] TxDOT says edge cracking can start from shrinkage of the asphalt at the edge or shrinkage cracks in the base or subgrade, with loads on the edge breaking it off.[5]

Dips and humps are structural. Depressions can be caused by settlement of the foundation soil or can be built up during construction.[1] A swell is usually caused by frost action in the subgrade or by swelling soil.[1] Standing water in a dip then speeds the damage. Cracks allow surface water to enter the subgrade and further destroy its stability.[5]

How wide is too wide

Federal highway inspectors grade block cracks by width: low severity at a mean width of 6 mm (about a quarter inch) or less, moderate up to 19 mm (about three quarters of an inch), and high above that.[2] A hairline crack is a maintenance item. A crack you can put a finger in is not.

What to do about it

One manufacturer's driveway guide sorts repairs by size: cracks up to half an inch wide get crack filler, holes up to an inch deep get a trowelled patch, and deeper holes get a pothole patch.[3] Cracks should be filled, and gas, oil or grease spots treated, before sealer goes on.[4] See how often a parking lot should be sealcoated for timing, and what sealcoating costs for how to compare bids.

Stop and call a pro if

  • Small many-sided pieces, rutting or pumping under the wheel paths. That is a base problem, not a surface problem.
  • Sunken areas, bulges or standing water. They point to settlement, frost action or drainage that needs correcting before any paving.
  • Edges breaking off or crumbling beside lawn, gravel or a ditch.
  • Cracks wider than three quarters of an inch, or a lot where the cracks are everywhere and keep coming back.

Asphalt paving and sealcoating is its own licensing specialty, abbreviated PAV, and its definition names parking lots.[6] Look the business up on DPOR's licence lookup before you sign.

Find help in Virginia

Read more commercial answers and browse parking lot maintenance businesses. When you are ready, describe your lot once and licensed local businesses will quote it.

Common questions

Is a cracked parking lot dangerous?
Wide cracks, potholes and raised edges are trip and vehicle hazards, and water that gets under the asphalt makes them worse. Mark and repair anything people walk across or cars hit first, and have a paving contractor assess the rest.
Can I just seal over the cracks?
No. Sealer is a thin coating, not a filler. Cracks should be filled, and gas, oil or grease spots treated, before sealer goes on, and pieces that are moving need repair, not coating.
What does alligator cracking mean?
It means the surface is failing under repeated traffic, usually over a weak or wet base. TxDOT says alligator cracking is generally caused by inadequate base support or a brittle surface. Expect a patch or section replacement, not crack filler.
Why do cracks keep coming back after filling?
Asphalt keeps shrinking and flexing with the seasons, so filler in a moving crack can open again. Cracks over a failing base or under a heavy wheel path will return until the cause is repaired.
Who can repair a parking lot in Virginia?
A business licensed in the asphalt paving and sealcoating specialty, PAV, whose definition names parking lots. Confirm the licence on DPOR's lookup before you sign.

Sources

  1. [1] Asphalt Surfaced Airfields PAVER Distress Identification Manual (June 2009), U.S. Army Corps of Engineers ERDC-CERL, published by the Federal Aviation Administration. Checked October 28, 2026.
  2. [2] Distress Identification Manual for the Long-Term Pavement Performance Program (FHWA-HRT-13-092, revised May 2014), Federal Highway Administration. Checked October 28, 2026.
  3. [3] How to seal an asphalt / blacktop driveway, Gardner-Gibson. Checked October 28, 2026.
  4. [4] Sealcoating FAQ, SealMaster. Checked October 28, 2026.
  5. [5] Flexible Pavement Distress Maintenance (Maintenance Operations Manual), Texas Department of Transportation. Checked October 28, 2026.
  6. [6] 18VAC50-22-30, Definitions of specialty services (Board for Contractors Regulations), Virginia Administrative Code, Virginia General Assembly. Checked October 28, 2026.

Want a pro to handle it?

Describe the job once. Licensed local businesses send quotes, and you pay only when you book one.