Walk an older driveway in fall and you'll often find them: small, cone-shaped craters where a piece of stone near the surface broke apart, a few shallow pits near the garage apron, a rough spot where the surface wore through. They look minor. Left open through a winter of thaws and freezes, though, they hold water and grit, and the edges can keep breaking down. The good news is that small pits are one of the easier concrete repairs a homeowner can make. The catch is that patches tend to come loose for a few common reasons, and cold weather is one of them.
What a popout actually is
Concrete is stone and sand held together by cement paste. A popout is a small, generally cone-shaped hole in the surface, left when a stone particle just under the surface fractured. Part of that broken stone is often still stuck in the bottom of the hole. Popouts run from about ¼ inch to a few inches across.
The usual cause is a porous, lightweight stone particle near the surface. It soaks up water, and when that water freezes it expands and cracks the particle and the thin layer of concrete above it. In some regions there's a second cause: certain sand or shale particles react chemically with the cement, swell, and pop off a small cone, sometimes with a damp-looking or discolored spot. Either way, popouts are mostly a surface problem, not a sign that the slab is failing.
Pits and scaling are related but different: the top layer of paste and sand wears or flakes away and leaves a rough, shallow dip. De-icers, plows, tires and years of traffic can speed that up.
Why driveway patches come loose
When a driveway patch comes loose after a winter, it's often for one of these common reasons:
- It was spread too thin. Our patches aren't made for thin overlays or skim coats, and a thin smear over a shallow dip isn't the kind of repair they're designed for.
- The edges were feathered out. Where a patch thins to nothing at the edge, that edge tends to break away first and can let water under the rest.
- The hole was dirty or dusty. Loose stone, grit and dust under a patch keep it from bonding.
- It went in too cold, or froze too soon. Cement-based patches need mild temperatures to set and harden. A patch that freezes before it has cured may not harden the way it should.
Pick the right patch
For driveways, sidewalks and patios, use High Strength Concrete Patch. It's our concrete flatwork patch: pre-blended (you add water and mix), placed up to 1½ inches thick in a single application, and finished by trowel or brush so it takes on the texture around it. It comes in New Concrete Gray and Aged Concrete Buff, in Quart and Gallon sizes. Aged Concrete Buff is the one to try first on older, weathered concrete.
It's a fit for popouts and pits that have some depth. It isn't meant for shallow, widespread scaling or feather-edged skim repairs. Before you start, check the package or ask us for the minimum depth, cure and traffic times, so your repair meets the product's requirements.
If the damage is on brick or stone steps by the drive rather than the slab itself, that's a job for Fast-Repair Patching Mortar, our patch for steps and other high-wear masonry. It begins setting in minutes and builds from ½ inch to 6 inches in lifts.
Color matters on a driveway because a patch sits in plain view, and older concrete is rarely the gray it was when it was poured. Before you mix for the whole driveway, a quart is a good way to test the color on a spot or two and see how it looks once dry. Expect a patch to blend, not to disappear.
How to patch pits and popouts, step by step
- Pick your day. Plan the work for a dry stretch when it's above 40°F, with no freeze in the forecast while the patch cures. Follow the directions on the package.
- Clean out the hole. Chip out any loose stone and broken concrete with a cold chisel and hammer until you reach solid concrete. Wear eye protection.
- Square up the edges. Chisel the edges so they drop straight down instead of tapering, so the patch doesn't thin out to a feather edge. If the damage is too shallow to meet the depth the package calls for, it isn't a fit for this patch; ask us before you start.
- Get it really clean. Brush and vacuum out the dust and grit. If the area has oil drips, clean those off first, since nothing bonds well over oil.
- Dampen the surface. Wet the hole with water so it's damp but has no standing water in the bottom.
- Mix. Wear gloves and eye protection. Add the least water that gives you a workable mix, let it rest 5 minutes, then remix.
- Pack it in and finish it. Press the patch firmly into the hole with a trowel so it fills the bottom and the edges, then smooth it level with the slab. As it sets, brush or tool the surface to match the texture around it. On a broom-finished driveway, a light pass with a brush usually blends best.
- Protect it while it cures. Keep fresh work from freezing while it cures, and keep it from drying out too fast in sun or wind. Keep cars off it until it has fully hardened; follow the package directions for timing.
If winter is already here
If the forecast has turned cold for good, it's fine to wait for spring. A patch placed in mild spring weather has a better chance than one that freezes before it cures. In the meantime, sweep the holes clear of grit, clear the driveway early so meltwater doesn't sit in the pits, and go easy on de-icers around the damaged areas.
Once it's patched
After the repairs have fully cured and dried (check the patch package for cure time before sealing), a penetrating, breathable water repellent such as Concrete Responder Sealer can reduce how much water the driveway soaks up while still letting vapor out. Less water in the surface means less for each freeze to act on. It's water-based, has a no-sheen natural finish, goes on by sprayer, roller or brush, and covers up to 250 sq ft per gallon. Apply it to clean, dry concrete, and try a small area first to check the look. It's a step for after the patching, not a substitute for it.
When a patch isn't enough
Patching is the right fix for scattered pits and popouts. If the slab has wide cracks that keep opening, sections that have sunk or heaved, large areas where the surface is scaling away, or crumbling that goes deep across much of the driveway, the problem is bigger than the surface. That's the point to have a concrete contractor take a look.
For more on keeping water from doing damage, read How to Protect Brick and Mortar Joints from Water Damage and Understanding Sealers vs. Water Repellents for Masonry Preservation. If the damage is on brick steps by the drive, see How Road Salt Breaks Down the Joints on Your Brick Steps.
Photo credit: Figure 3 from Md. Safiuddin, “Concrete Damage in Field Conditions and Protective Sealer and Coating Systems,” Coatings 2017, 7(7), 90, https://doi.org/10.3390/coatings7070090. Licensed under CC BY 4.0; no changes made other than display sizing.