Two products sit side by side under the label “driveway sealer,” and they do almost opposite jobs. An asphalt sealcoat is a film that sits on top of the surface. A sealer for concrete, done well, is a liquid that soaks in and leaves nothing on top at all. Put the wrong one on the wrong surface and it does not just underperform. A film on a concrete slab can trap the moisture it was supposed to keep out. So the first decision is not which brand to buy but what your driveway is made of.
Asphalt: A Sealcoat Is a Film, and the Chemistry Matters
Asphalt sealcoat is a thin protective layer that shields the pavement from sun, water and oil. The label tells you which chemistry you are buying, and one difference is worth checking before anything else: coal tar versus asphalt-based.
The U.S. Geological Survey reports that coal-tar-based sealcoat typically contains 35,000 to 200,000 mg/kg of polycyclic aromatic hydrocarbons (PAHs), about 1,000 times more than sealcoat with an asphalt base. In its studies, house dust in apartments whose parking lots were sealed with coal tar carried 25 times the PAHs of dust in apartments with other parking surfaces. That is why Austin banned coal-tar sealers in 2006, and why New York now prohibits both selling and applying them. The state points to asphalt-based sealants as the alternative. Rules vary by state and town, so read the label and check your local regulations. The full numbers are on the USGS page on coal-tar sealcoat.
Timing and Prep Decide How Long a Sealcoat Lasts
Most failed sealcoat jobs trace back to the conditions, not the product.
- Fill cracks first. A film over an open crack bridges the gap while the crack keeps moving, and the coat splits along the same line. Fill, let the filler cure, then seal. Our guide to asphalt crack fillers covers which filler suits which crack.
- Do not seal brand-new asphalt right away. Paving contractors commonly advise waiting several months, often six to twelve, so the fresh surface can cure. If the pavement still looks glossy and oily, it is too new.
- Clean the surface. Sweep or wash off dirt and loose material and let it dry fully. Sealer bonds to pavement, not to grime.
- Watch the weather. Most labels call for warm, dry conditions and no rain for the first day or so. Cool, humid or cloudy weather slows curing.
- Expect to repeat it. Contractors commonly recommend resealing asphalt every two to three years.
A Rubberized Sealcoat for Cracked, Worn Asphalt
For an older blacktop driveway with fine cracks and worn spots, Black Jack Drive-Maxx 1000 is a water-based rubberized sealer that adds latex polymer and urethane to the mix, with sand in it to fill small cracks. The manufacturer says it can be applied down to 45 degrees Fahrenheit, calls for two coats, and lists about an hour to foot traffic and a day before vehicles go back on it in good conditions. It is sold as a 10-year product, and the same line includes a 7-year Drive-Maxx 700 at a lower tier. Published coverage figures run roughly 300 to 350 square feet per five-gallon pail, and buyers report that it is thick, so a rough or worn surface can take more than you planned for. At the time of writing it shows about 4.6 stars across roughly 120 ratings. Large cracks and holes still need a proper filler or patch first, because the sand only helps with small ones. Check the label for coal tar content before you buy, as with any sealcoat. This is an affiliate link (see our disclosure for details).
Concrete: Seal Inside the Surface, Not On Top of It
A plain, undecorated concrete driveway usually calls for a penetrating sealer, typically a silane or siloxane. It soaks into the pores and reacts there to repel water, and it leaves no film that can peel. That matters because concrete has to be able to release moisture vapor from below. Film-forming sealers can trap it, and in a climate that freezes, trapped water can lead to a cloudy, blistered or peeling film and to surface scaling. Penetrating sealers also do not change the look of the slab, which is why they suit driveways that are not meant to look wet or glossy.
The trade-off is that a penetrating sealer does not fill cracks and does not repair a damaged surface. It protects sound concrete from water and de-icing salt. Seal after the slab has cured, after any crack repair is done, and on a dry, clean surface.
A Penetrating Sealer for Plain Concrete
Foundation Armor SX5000 is a solvent-based silane-siloxane water repellent for unsealed concrete, brick and pavers. The manufacturer’s figures are up to 175 square feet per gallon on porous concrete and up to 200 to 225 on smooth, prepared concrete, with two coats recommended for even coverage, application between 55 and 85 degrees, and 24 hours before the surface sees moisture. It states the sealer will not change the look or color of the surface and that protection can last up to seven to ten years. Because it is solvent-based, follow the label on ventilation and flammability. At the time of writing it shows about 4.4 stars across roughly 70 ratings. One gallon covers a small slab, so measure your driveway before ordering. This is an affiliate link (see our disclosure for details).
When a Sealer Is the Wrong Answer
A sealer protects a surface that is still sound. It does not repair one that is failing.
- Asphalt with connected cracking, sinking or potholes has a base problem. Patching or resurfacing comes before any sealcoat, and a contractor should look at the base.
- Concrete with open cracks needs a crack repair first. See our guides to concrete crack fillers and to floor cracks under vehicle traffic.
- Concrete that is already flaking or scaling is past what a penetrating sealer can fix. A concrete resurfacer may be the next step, and the slab should be sound before you seal it.
If the slab is cracked through, sinking or beyond a DIY repair, you can compare local concrete repair pros on Angi. This is an affiliate link (see our disclosure for details).
Etienne Basson maintains and repairs his own home, and writes practical guides on choosing the right materials and products for repair and finishing jobs: fillers, sealants, adhesives, and similar. He focuses on what actually works for a specific job, not just a spec sheet.