Crack filling is the highest-return maintenance there is on an asphalt driveway, and it is the one most people put off. An open crack is a funnel: it delivers surface water straight into the aggregate base, where it washes out fines, undermines support, and — in a freeze-thaw climate — expands as ice and widens the crack that let it in.
A crack you fill this autumn costs a few dollars. The same crack left three winters becomes alligator cracking, and that is a full-depth patch. The economics are not close.
The Filler Types
Rubberised Asphalt Emulsion (Cold-Pour)
The consumer default, sold in squeeze bottles and pourable jugs. Asphalt emulsion modified with latex or rubber polymers for flexibility, applied cold straight from the container.
The rubber content is what matters. Asphalt alone is brittle at low temperatures and a plain emulsion filler cracks straight through its first winter. Polymer-modified products stay flexible through the thermal cycling that opens and closes a crack seasonally — a crack in a driveway can move measurably between a summer afternoon and a January night, and the filler has to move with it.
Expect two to four years from a quality rubberised cold-pour filler, less in severe climates.
Hot-Applied Rubberised Crack Sealant
What road crews use. Solid rubberised blocks melted in a kettle and applied hot, bonding into the crack walls as they cool. Substantially more durable than cold-pour — five to eight years is realistic — because the material flows into the crack under heat and achieves a genuine bond rather than sitting in it.
The barrier is equipment. Melter kettles are a rental proposition and the material is hot enough to cause serious burns. For a homeowner with a few cracks it is not worth it; for a long driveway or a small commercial lot, hiring a crew who hot-apply is worth asking about.
Trowel-Grade and Textured Fillers
Thicker, more paste-like products for wider cracks and shallow depressions, applied with a trowel or putty knife. Many include sand or fine aggregate to match the surrounding texture, which matters visually — a smooth black stripe across a textured driveway is conspicuous.
Cold-Patch Asphalt
Not strictly a crack filler but the correct material once a crack exceeds about half an inch, or where a crack has widened into a channel. Aggregate-bearing asphalt applied cold, compacted in lifts. See our driveway repair guide for the full method.
Concrete Crack Fillers — A Different Product
Asphalt fillers are formulated to bond to asphalt and stay flexible in a flexible pavement. Concrete crack fillers are typically polyurethane, silicone or cementitious, formulated for a rigid substrate and for concrete's alkalinity. They are not interchangeable, and an asphalt product on a concrete driveway both looks wrong and bonds poorly.
Filler Types Compared
| Type | Crack Width | Life | Cost | DIY |
|---|---|---|---|---|
| Rubberised cold-pour | Up to 1/2 in. | 2 – 4 years | Low | Yes — the default |
| Trowel-grade filler | 1/4 – 1 in. | 2 – 4 years | Low | Yes |
| Hot-applied rubberised | Up to 1 in. | 5 – 8 years | Medium (equipment) | Rental or contractor |
| Cold-patch asphalt | Over 1/2 in. | 3 – 8 years | Low | Yes, with compaction |
| Backer rod + filler | Deep cracks | Extends filler life | Very low | Yes |
| Full-depth patch | Alligatored areas | 10+ years | High | Possible, hard work |
What Actually Distinguishes a Good Filler
Polymer content. The single most important specification and the one least clearly labelled. Look for "rubberised", "polymer-modified" or "latex-modified" on the label. Plain asphalt emulsion is cheaper and cracks through its first freeze.
Stated temperature range. Products list an application temperature range and, sometimes, a service range. A filler rated to stay flexible at low temperatures is what survives a northern winter.
Solids content and shrinkage. Fillers shrink as water or solvent leaves. High-solids products shrink less, which is why a deep crack often needs a second application after the first has cured and settled — plan for it rather than being surprised.
Delivery format. Squeeze bottles suit narrow cracks and give control. Pour spouts suit long straight cracks. Buckets with a trowel or squeegee suit wide cracks and large volumes. Cartridge tubes in a caulk gun suit short, precise work.
Sand content. A filler with aggregate texture blends visually with the driveway surface. A smooth glossy filler leaves a visible line, particularly noticeable after sealcoating, when the smoother filler reflects differently from the surrounding surface.
How to Fill Driveway Cracks Properly
1. Clean the Crack Out Completely
This is where most repairs are won or lost. Filler bonds to the crack walls, and it cannot bond through dirt, sand, dead vegetation or old failed filler. Use a screwdriver or a crack-cleaning tool to rake debris out of the full depth, then blow it clear with a leaf blower or compressed air.
A wire wheel on a drill or a dedicated crack-cleaning brush does a much better job than a broom on cracks that have been open a while.
2. Kill Vegetation at the Root
Grass and weeds growing in a crack have roots below the surface. Pull the visible growth and treat the root with a suitable herbicide, then let it die back before filling. Filling over live roots means the plant simply reappears through your repair.
3. Dry It Out
Cold-pour fillers need a dry crack. Water in the crack prevents adhesion and can cause the filler to foam or fail. Give the driveway 24 dry hours, and on a stubborn damp crack a heat gun clears residual moisture.
4. Use Backer Rod in Deep Cracks
A crack more than about half an inch deep should be filled to within roughly half an inch of the surface with foam backer rod pushed down into it. This is not just economy, though it does save a lot of filler. A filler bonded on two faces — the crack walls — can stretch and compress as the crack moves. One that has also bonded to the bottom is restrained in three directions and tears instead. Backer rod creates the correct two-sided bond geometry.
5. Fill Slightly Proud, in Layers
Overfill very slightly to allow for shrinkage as the filler cures. In deep cracks, apply in layers with drying between rather than one deep pour, which skins over and stays soft underneath.
6. Level It
Squeegee or trowel the surface flush with the driveway. A raised bead of filler catches snow shovels and plough blades and gets torn out; a depression collects water.
7. Cure Before Traffic and Before Sealcoating
Most cold-pour fillers accept foot traffic in a few hours and vehicles in 24. If you plan to sealcoat, most manufacturers want the filler fully cured first — commonly 24 to 48 hours, sometimes longer for deep fills. Sealing over uncured filler traps solvent and leaves a soft stripe.
When to Do It
Autumn is the best time, for two reasons. Cracks are at or near their widest as temperatures fall, so the filler goes in at maximum opening and is compressed rather than stretched as the pavement expands in summer — which is the easier direction for the material. And filling before winter keeps water out of the base during the freeze-thaw season, which is when an open crack does the most damage.
Spring is the second-best window and lets you address the damage winter caused. Avoid high summer, when cracks are at their narrowest and asphalt is soft.
Conditions: above 50°F and rising, no rain forecast for 24 hours, and a dry crack. Most cold-pour fillers state a minimum application temperature and mean it.
Crack Filling and Sealcoating Are Different Jobs
People routinely conflate the two, and the order matters. Sealcoat is a surface treatment — a thin coating that protects the asphalt binder from UV, fuel and oil. It has no structural function and it does not fill anything wider than a hairline.
Crack filler is a repair material that stops water entering the base. It addresses a structural problem.
The correct sequence is always: clean, fill the cracks, let the filler cure, then sealcoat over the top. Sealcoating a cracked driveway without filling first produces a driveway that looks uniformly black for a season and has done nothing about the water still running into its base. Our driveway sealing cost guide covers the sealcoating side.
When Filling Is the Wrong Answer
Alligator cracking — interconnected cracks forming small polygons — means the base beneath has failed and the asphalt is flexing under load with nothing solid to bear on. Filling those cracks achieves nothing; they reappear in the same pattern within a season because the cause is entirely underneath. That area needs cutting out, the base rebuilding, and repaving.
Depressions that hold water indicate base settlement. Filling the cracks in a birdbath does not address why the ground moved.
Very widespread cracking — beyond roughly a quarter of the driveway — has passed the point where repair is economic, and resurfacing or replacement is the better spend.
The screwdriver test settles it: push a long screwdriver into the affected area with firm hand pressure. If it stops in the first few millimetres, the problem is at the surface and filling works. If it sinks an inch or more, or the asphalt flexes under pressure, the base has failed.
The Short Version
Buy a polymer-modified rubberised cold-pour filler for cracks up to half an inch, in a delivery format that suits the crack width you actually have — and buy more than one format if your driveway has a range. Look for "rubberised" or "polymer-modified" on the label, because plain asphalt emulsion cracks through its first winter.
Clean the crack to full depth, kill any vegetation at the root, dry it, use backer rod in anything deep, fill slightly proud in layers, and level it flush. Do it in autumn if you can.
Then, once it has cured, sealcoat over the top. And check the screwdriver test first — if the base has failed, no filler will help.
Frequently Asked Questions
A polymer-modified rubberised cold-pour filler, for cracks up to about half an inch, which covers most residential driveways. The critical specification is the rubber or polymer content — look for 'rubberised', 'polymer-modified' or 'latex-modified' on the label. Plain asphalt emulsion without polymer is cheaper and goes brittle in cold weather, cracking straight through its first winter, because a driveway crack moves measurably between a summer afternoon and a January night and the filler has to move with it. Expect two to four years from a quality cold-pour product. Hot-applied rubberised sealant lasts five to eight years but needs a melter kettle, which puts it in contractor or rental territory rather than homeowner DIY.
Up to about half an inch with a pourable or squeeze-bottle rubberised filler, and up to roughly an inch with a trowel-grade filler or cold-patch asphalt. Beyond that, or where cracks have interconnected into a pattern resembling reptile skin, filling is the wrong repair — that is alligator cracking, which means the base beneath has failed and the asphalt is flexing under load. Filled cracks in an alligatored area reappear in the same pattern within a season because the cause is entirely underneath the surface you treated. Test it with a long screwdriver pushed in under firm hand pressure: if it stops in the first few millimetres the problem is at the surface; if it sinks an inch or the asphalt flexes, the base needs rebuilding.
Yes, in anything more than about half an inch deep, and the reason is mechanical rather than economic — though it does save a lot of filler. A sealant bonded on two faces, the two crack walls, can stretch and compress freely as the crack opens and closes with temperature. One that has also bonded to the bottom of the crack is restrained in three directions, so instead of stretching it tears, usually along the bond line. Pushing foam backer rod down so the filler occupies only the top half-inch or so creates the correct two-sided bond geometry and meaningfully extends the repair's life. It is a few dollars of material that changes how long the job lasts.
Autumn, for two reasons. Cracks are at or near their widest as temperatures drop, so filler goes in at maximum opening and then gets compressed rather than stretched as the pavement expands in summer — compression is the easier direction for the material to handle. And filling before winter keeps water out of the aggregate base through the freeze-thaw season, which is precisely when an open crack does the most damage, washing out fines and widening as ice expands. Spring is the second-best window and lets you address winter's damage. Avoid high summer, when cracks are narrowest and the asphalt is soft. Whenever you do it, work above 50°F and rising, with a dry crack and no rain forecast for 24 hours.
Before, always, and let the filler cure first. The two jobs are commonly conflated but they do different things: sealcoat is a thin surface treatment protecting the asphalt binder from UV, fuel and oil, with no structural function and no ability to fill anything wider than a hairline. Crack filler is a repair material that stops water reaching the base, which is a structural problem. Sealcoating a cracked driveway without filling first gives you a uniformly black surface for a season while water continues running into the base underneath. The sequence is clean, fill, cure — most manufacturers want 24 to 48 hours, longer for deep fills — then sealcoat over the top, since sealing over uncured filler traps solvent and leaves a soft stripe.
Four usual causes. The crack was not cleaned to full depth, so the filler bonded to dirt and old material rather than to the crack walls. Vegetation was filled over while still alive, and the roots simply pushed back through. The filler was not polymer-modified, so it went brittle in cold weather and split down the middle at the first hard freeze. Or the filler bonded to the bottom of a deep crack as well as the sides, leaving it restrained in three directions so it tore instead of stretching — the problem backer rod solves. If cracks reappear in the same interconnected pattern rather than as individual lines, none of those is the issue: that is alligator cracking from base failure, and no filler will hold it.
No — they are formulated for different substrates and behave differently. Asphalt fillers are asphalt-based, bond to like materials, and are designed to stay flexible in a flexible pavement that moves substantially with temperature. Concrete crack fillers are typically polyurethane, silicone or cementitious, formulated to bond to a rigid, highly alkaline substrate that moves far less. Using an asphalt product on concrete gives poor adhesion and a black stripe that looks conspicuously wrong on grey concrete. For a concrete driveway, use a self-levelling polyurethane sealant for moving joints and cracks, or a cementitious patching compound for wider damage, and match the finish texture where you can.
Two to four years for a quality polymer-modified cold-pour filler, and five to eight for hot-applied rubberised sealant, which is what road crews use. Climate is the biggest variable after product quality: severe freeze-thaw cycling shortens every figure, because the crack is opening and closing further and more often. Preparation matters nearly as much — a crack cleaned to full depth with dead vegetation removed and backer rod in the deep sections will substantially outlast the same product poured into a dirty crack. And a filler left proud of the surface gets torn out by snow shovels and plough blades, so levelling it flush is part of making it last.