What’s the best fix for deep cracks that are widening? It depends on what’s cracking and whether it’s still moving. You either seal it correctly to keep water out, or you stop and address the underlying shift.
If you’ve already tried a tube of filler and the crack still opens up, you’re not dealing with a simple “fill the gap” problem. What’s really happening is either the surface is moving or water is getting in. It’s like a loose hinge: it only gets worse when you ignore it. The right next step changes based on whether the crack runs through a foundation or load-bearing area, or concrete flatwork like a driveway or patio. This guide helps you sort it fast, spot the red flags (like a gap around 1/4 inch or offset edges), and choose the most cost-effective path: monitor it or seal it with a flexible product the right way.
First Decide What’s Cracking
A widening crack isn’t one problem, it’s a location problem. Which repair makes sense hinges on whether it’s structural (load-bearing) or just a slab. If you treat them all like a simple gap to fill, you will waste money and hide movement that needs attention.
Start by sorting it into one of these buckets:
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Foundation or load-bearing structure (foundation wall, support pier, beam, column, structural slab): if the crack keeps widening or you can fit about a 1/4-inch gap, skip patching and get a pro opinion using Better Business Bureau (BBB) contractor ratings as a quick filter. Filling can make it look better while the structure keeps moving.
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Concrete flatwork (driveway, walkway, patio, garage slab): wide/deep cracks often mean the slab or base is shifting, especially with water and sandy soils common around Wilmington. Surface filler alone tends to reopen if movement continues.
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Asphalt (blacktop driveway): widening cracks usually act like a water channel. Sealing can help when it’s isolated, but if you’re seeing lots of cracking, the more durable path often shifts toward resurfacing or section replacement.
Next step: take two photos today (one close-up with a coin for scale and one wider shot showing where it runs), then track whether it changes over 2 to 4 weeks.
Cracks that keep widening after a basic patch are usually a sign the underlying issue is movement or moisture, not just a surface gap. Read more in our article: Cracks Keep Coming Back
Red Flags That Change the Fix
You patch it on Saturday, and by the next big rain the same crack has reopened and the edge feels a little higher underfoot. At that point, shift from cosmetic patching to checking for movement and washout.
These are the canaries in the coal mine for shifting and washout.
In coastal areas, repeating cracks plus wetness or washout often trace back to drainage and water management problems around the slab or base. Read more in our article: Concrete Or Asphalt Drainage
| Red flag | What it suggests | What to do next |
|---|---|---|
| Gap is around 1/4 inch or more | Likely movement and/or a base problem (not just a void) | Escalate beyond simple patching; evaluate for stabilization/repair |
| One side sits higher/lower than the other | Movement/offset edges | Escalate; patching usually won’t last |
| It stays wet or you see washout/sand after rain | Water intrusion and base issues | Prioritize stopping water entry; investigate base/void issues |
| Crack reopens in the same place after past repairs | Ongoing movement | Stop chasing with filler; it’s a band-aid fix; consider stabilization/section repair |
| Repeating pattern (multiple cracks, spidering, long continuous line) | Broader movement/base problem | Escalate; consider more durable repair path (stabilization/section repair) |
Best Fix for Widening Deep Cracks
Sometimes the crack keeps growing despite filler, and the first real clue is when storms push water through it. The turning point is treating it like a movement problem, not a gap problem.
What matters most is whether the crack has stopped changing or it’s still active. If your photos show no change after heavy rain or a few weeks, monitor and keep water out. If it’s widening but isolated (common in asphalt or flatwork), your best DIY is a flexible seal built the right way. Anything else is asking for a callback. Pack backer rod down so you’re sealing the top, not creating a thick, rigid plug that pops out.
If the gap is around 1/4 inch or edges are offset, stop chasing it with filler (when to replace roof vs repair cracks). Your next step is stabilization or section repair (slab lifting/void fill, asphalt patch/overlay), and if repairs start approaching about half the cost of replacement, replacement is usually the smarter spend, like the budget reality checks you hear on This Old House.
Roof not getting any younger? Contact us at Contact us or call 910-241-1152 to find out where you stand.
