How Asphalt Crack Sealing Works

What is Asphalt Crack Sealing and how does it work?

Asphalt crack sealing is the process of cleaning out cracks in your driveway and filling them with a rubberized sealant that flexes with the pavement. It keeps water from getting underneath and turning small cracks into big problems.

Think of your driveway like a windshield. A tiny chip is annoying, but if you ignore it, a crack spreads across the whole thing. Same deal with asphalt. Water gets into any opening, freezes in the winter, expands, and makes the crack bigger. Then more water gets in, and pretty soon you've got a pothole.

Crack sealing is that cheap fix that stops the cycle. We clean out the crack, sometimes with a wire brush or compressed air, then fill it with a hot rubberized material. That goo is designed to stay flexible, so it moves with the pavement as the ground shifts and the temperature changes. It doesn't just sit there like a rigid plug that cracks out in a season.

We use a hot-applied rubberized asphalt, the same stuff used on highways. It's not the cold pour you buy in a bucket at the hardware store. That stuff works for tiny hairline cracks, but it doesn't have the same flexibility or lifespan. We heat it to around 400 degrees and apply it with a wand that forces it deep into the crack.

The goal is to seal the crack from top to bottom, not just smear a bead on the surface. If you only cover the top, water still finds its way in from the sides. That's why we take the time to clean the crack first. Loose dirt, old sealant, and plant roots all have to go, or the new material won't stick.

• Cleaning and filling cracks with a flexible, rubberized sealant
• Keeps water from getting under the asphalt and causing bigger damage
• A quick, low-cost fix compared to patching or repaving
• Best done before winter to avoid freeze-thaw damage

How Asphalt Crack Sealing works, start to finish

The process is straightforward: clean the crack, fill it with hot rubberized sealant, and let it cool. But the details matter, and that's where our crews earn their keep.

First, we walk the whole driveway and mark every crack that needs attention. Not all cracks are the same. Hairline cracks might just need a surface treatment, while wider ones need a deeper fill. We also look for signs of bigger issues, like alligator cracking or a soft base, because sealing over those is a waste of money.

Next comes the cleaning. We use a combination of wire brushing and compressed air to get out loose debris. If the crack is full of dirt and grass, we might use a router to widen it slightly, which gives the sealant a clean edge to bond to. Routing also creates a reservoir so the sealant sits slightly below the surface, which means traffic doesn't wear it out as fast.

Then we heat the sealant in a melter. It's a lot like a giant crock pot on wheels. The material has to be hot enough to flow into the crack but not so hot that it burns. We apply it with a wand that has a shoe on the end, which presses the material into the crack and smooths it out as we go.

After the sealant is in, it needs time to cool. That's usually 15 to 30 minutes, depending on the weather. We'll block off the area with cones or caution tape so nobody drives on it while it's still soft. Once it's set, it's fine to drive on, but we recommend waiting a full day before any heavy traffic, like a parked car or a truck.

The whole job for a typical two-car driveway takes a few hours. We'll sweep up any loose debris and leave the place looking clean. You won't even notice the sealant unless you look close, because we match the color to the asphalt as best we can.

One thing we see a lot in Huntsville is people trying to do this themselves with a bucket of cold pour from the hardware store. That stuff works in a pinch for a season, but it doesn't have the flexibility of hot-applied rubberized sealant. It gets brittle in the winter and pops out in chunks. Then you're back to square one, and the crack is worse.

We've also seen crews that just blow the leaves out and call it clean. That's not enough. If the crack is packed with dirt, the sealant won't stick, and it'll fail within months. We take the time to do it right, because a redo is bad for you and bad for our reputation.

1. Inspect and mark.We walk the driveway, note every crack, and check for signs of structural damage.
2. Clean and prep.Wire brush, compressed air, and sometimes a router to give the sealant a clean edge.
3. Heat and apply.Hot rubberized sealant is applied with a wand, pressed deep into the crack.
4. Cool and cure.We block off the area until it's set, usually 15 to 30 minutes.
5. Final sweep.We clean up, and you're good to go.

Why Asphalt Crack Sealing matters for your home

Crack sealing is the cheapest thing you can do to protect your driveway. It costs a fraction of a patching job, and it can add years to the life of your asphalt.

Your driveway takes a beating. Cars, trucks, the sun, and Huntsville's weather all work against it. Summers get hot enough to soften the asphalt, and winters bring enough freeze-thaw cycles to crack it. Water is the main threat, though. Once it gets under the surface, it washes out the base, and then you're looking at sinkholes and potholes.

Sealing cracks is like putting a bandage on a cut before it gets infected. It's a small effort that prevents a big problem. A crack that's a quarter-inch wide can turn into a pothole the size of a dinner plate within a year or two, especially if we get a wet spring.

We've seen driveways that were neglected for years. The cracks are full of grass, and the edges are crumbling. At that point, crack sealing isn't enough. You need patching or even a full repave. That's a lot more money. Regular crack sealing every couple of years is a whole lot cheaper than either of those.

There's also the look of the thing. A driveway full of spiderweb cracks makes your whole house look tired. Sealing them up makes a noticeable difference, and it's a quick win if you're thinking about selling. Buyers notice a clean, well-maintained driveway.

Now, crack sealing isn't a miracle fix. If your driveway has alligator cracking, which looks like reptile skin, or if there are areas that have sunk, sealing won't help. Those are signs of a failed base, and they need structural repair. But for the common straight cracks, edge cracks, and even some block cracks, sealing is the right call.

We get asked a lot if crack sealing is the same as sealcoating. They're different. Sealcoating is a thin protective layer over the whole surface, like sunscreen. Crack sealing is a targeted fix for specific openings. You can do both, and they work well together, but they solve different problems.

If you're in Huntsville and you're not sure whether your driveway needs crack sealing or something more, give us a call. We'll take a look and tell you straight what we'd recommend, even if it's just a patch job we can do in an afternoon.

Common problems and what causes them

Most cracks come from water, tree roots, or poor installation. Knowing the cause tells you whether sealing will help or if you're just covering up a bigger problem.

The most common crack we see in Huntsville is the edge crack. That's where the driveway meets the grass. It happens because the base underneath the edge isn't as solid as the center, and water runs off the lawn and under the asphalt. Over time, the edge sinks and cracks. Sealing these is important, but you also want to make sure your downspouts drain away from the driveway.

Tree roots are another big one. We have a lot of mature oaks and maples here, and their roots love the moisture under a driveway. They'll push up the asphalt, causing cracks that look like a spiderweb. Sealing those won't help because the root is still pushing. You might need to cut the root, but that's a job for an arborist, not us.

Then there's the driveway that was installed poorly in the first place. Maybe the base wasn't compacted enough, or the asphalt was laid too thin. That's when you get alligator cracking, which is a sign of structural failure. Sealing it is like putting makeup on a broken leg. It'll look fine for a minute, but it won't hold.

Weather plays a part too. Huntsville gets hot summers that soften the asphalt and cold snaps that make it brittle. That constant expansion and contraction creates stress cracks. They're usually straight and run across the driveway. Those are perfect candidates for sealing.

One thing that surprises people is that oil and gas leaks from cars can eat asphalt. If you park the same spot every day and see dark, soft spots, that's a chemical breakdown. Sealing over that won't work because the damage is deeper. You'd need to patch that area first.

We also see cracks that come from poor drainage. If water pools on the driveway and sits there, it seeps into the smallest opening and does its damage. That's why we always check the grading when we're out for a seal job. If we can fix the drainage, the sealant will last a lot longer.

• Edge cracks from water runoff and weak base
• Tree roots pushing up from below
• Alligator cracking from a failed base
• Stress cracks from temperature swings
• Oil and gas spills eating the asphalt

Frequently Asked Questions