How Potholes Start in an Asphalt Driveway

A pothole is the end of a water-and-traffic story, not a random bite out of sound pavement. The mat breaks up after the support under a crack, seam, or thin spot stops holding still.

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Where the first break begins

A driveway pothole rarely opens in the middle of intact, well-supported asphalt. It starts where a crack, a construction seam, a thin edge, or the border of an old patch already let water through. That water softens the base or the soil, the asphalt flexes under tires, and small pieces break loose. In a freezing climate the same water expands as ice, lifts a chip of pavement, and leaves a void when it thaws. The next rain carries a little more fine material away, so the following wheel drops deeper. Holes therefore show up in wheel paths, at the street apron, and wherever a roof leader has been soaking one corner. The surface you notice failed after the layer under it moved.

Why the hole gets wider

Once a piece is gone, the edge of the remaining mat is a cantilever. Each tire strike breaks another fragment, and standing water keeps the base soft. Turning wheels grind the rim. A plow or a metal shovel can hook the lip and tear a larger slab. Cold nights refreeze whatever drained into the cavity, so a modest spring hole can double before summer. Filling only the visible opening, without drying the cavity or understanding why water arrives there, leaves the same engine running. A skin of sealer brushed over the area does not replace lost support, and it will map into the same shape after the next wet week.

What a lasting response looks like

Treat the cause in the same visit as the hole. Divert the roof water or the low spot that feeds it. If the base is mush, dig that mush out and replace it with compacted crushed stone in thin lifts rather than setting mix on mud. Square the opening, keep the walls rough and vertical, and fill with hot mix when a plant can supply it. Cold patch is a temporary hole fill that buys time until that hot mix, not a new driveway in a bag. If holes are appearing in a pattern across the wheel paths, the pavement may be tired or thin, and a series of plugs will not rebuild it. Ask a paving contractor to look at drainage and thickness before you buy another pallet of patch.

A practical sequence

Find where water enters: a crack, a seam, a downspout, or a low spot.
Note whether fines or mud are pumping out, which points to a weak base.
Dry and square the hole, then fill it temporarily or with hot mix.
Fix the water source so the same cavity does not reopen next spring.

The mistake to skip

Packing cold patch into a wet, round hole and calling it a permanent repair.

Questions people ask

Can sealer stop a pothole from forming?

Sealer can slow water entering hairline surface cracks on sound pavement. It cannot bridge an open hole or restore a base that is already moving.

Why do potholes show up in March?

Winter water freezes in small cracks, thaw leaves voids, and traffic knocks the loose pieces out as soon as the surface softens.

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