If you own an asphalt driveway or parking lot, you've probably heard that you should be sealcoating it. But most explanations of what sealcoating actually is — and what it does — are either too vague to be useful ("protects your asphalt!") or written to sell you something. This is neither.
The basics: what sealcoating is
Sealcoating is a liquid coating applied to the surface of asphalt pavement. The product — typically a coal tar or asphalt emulsion — dries to form a thin, dense protective layer over the top of the existing asphalt.
That's it. It is not a repair product. It does not bond asphalt back together, fill structural cracks, or fix anything that's already broken. What it does is slow down the rate at which your asphalt deteriorates.
What sealcoating protects against
Asphalt is held together by a binder — a petroleum-based material that, over time, gets attacked from multiple directions at once. Understanding what's breaking your pavement down is the best way to understand what sealcoating is actually defending against.
UV rays. Sun exposure is the biggest long-term enemy of asphalt. Ultraviolet light oxidizes the binder, causing the surface to fade from black to gray, become brittle, and start to crumble at the edges. Sealcoating reflects UV rays, dramatically slowing oxidation.
Water infiltration. Water is the second major threat, and in New England it's particularly damaging. Once water gets into the asphalt — through surface cracks, open joints, or a deteriorated surface — it can reach the sub-base below. In Rhode Island winters, that water freezes, expands by about 9% in volume, and mechanically widens cracks from the inside. When it thaws, the crack is bigger than it was before. Repeat that 30–50 times in a single winter and small cracks become serious structural problems. A sealed surface gives water far fewer entry points.
Oil and fuel contamination. Petroleum products — gas drips, motor oil, hydraulic fluid — soften and dissolve the asphalt binder on contact. Over time, this creates soft, deteriorating spots that lose their structural integrity. Sealcoating provides a barrier that petroleum products can't easily penetrate, protecting the asphalt underneath.
General wear and abrasion. Vehicle tires, plow blades, foot traffic — all of these erode the surface layer of asphalt. The sealer takes the brunt of this abrasion, wearing down gradually over two to three years rather than the asphalt itself.
What sealcoating does NOT do
This is the part of the explanation that tends to get left out, because it limits what a contractor can sell you. We'd rather be upfront about it.
Sealcoating does not repair cracks. It bridges over small surface hairline cracks — cosmetically filling them at the surface — but it does not structurally repair them, and it does not prevent existing cracks from continuing to grow once water gets underneath. For cracks you can see and feel, the correct approach is to fill them first, then seal over them. Sealer applied over open cracks traps any moisture already present underneath and accelerates the very damage you're paying to prevent.
Sealcoating cannot fix spider cracking. Spider cracking — the web of fine interconnected cracks that fans out across an area of pavement — indicates that the problem has moved beyond the surface. By the time pavement reaches that stage, the sub-base has been compromised. Filling individual spider cracks doesn't reverse base damage. What crack filling can do, in this situation, is fill around the spider-cracked area to stop the damage from spreading into surrounding pavement that's still intact. But the spider-cracked area itself needs a different solution — patching or repaving — not sealcoating.
Sealcoating is not a substitute for maintenance. It slows deterioration; it does not stop it. A driveway that's been neglected for 15 years won't be restored by sealcoating. Think of it the way you think of waxing a car: it protects a surface that's in reasonable shape, but it doesn't undo rust or structural damage.
Hand-brushing vs. spray application
Not all sealcoating is applied the same way, and the difference matters.
Hand-brushing is the right method for residential driveways. A brush works the sealer directly into the surface — into the texture and micro-pores of the asphalt — rather than just laying it on top. The result is better adhesion and more thorough penetration than spray or squeegee can achieve. It's slower and more labor-intensive, which is why some contractors skip it, but it's the method that produces a longer-lasting result on a driveway.
Spray application is the right method for large commercial parking lots, where hand-brushing thousands of square feet isn't practical. Spray covers large surfaces quickly and consistently when applied at the correct dilution rate. This is how commercial sealcoating jobs are typically handled.
On very long residential driveways where hand-brushing the full surface isn't practical, spray is also used — but the default for a standard driveway is brush. If a contractor quotes you a residential job and mentions spray as the standard approach, that's worth asking about.
How often should you sealcoat?
For most driveways in Rhode Island, the right cycle is every 2–3 years. Shorter than 2 years and you're over-sealing — building up product that doesn't fully cure and can actually make the surface slippery. Longer than 3 years and you're letting UV and water damage accumulate faster than the sealer can protect against.
For commercial lots, high-traffic volume and more aggressive wear from heavier vehicles typically push the maintenance cycle to every 2–3 years as well, though high-abuse lots may need attention closer to every 2 years. A commercial sealcoating assessment should factor in vehicle types, lot usage, and the condition of the current surface — not just a calendar.
The right sequence: crack filling first, then sealing
If your pavement has active cracks — cracks you can see, feel, or fit a coin into — the correct sequence before any sealcoating job is:
- Identify all cracks and map what type they are
- Dig out loose material by hand and clean the crack walls
- Fill with hot rubberized crack filler, which bonds to both sides and stays flexible through temperature changes
- Allow filler to cure
- Apply sealer over the filled surface
Skipping crack filling and going straight to sealing is a shortcut that backfires. The sealer covers the crack opening cosmetically, but any moisture underneath continues doing damage through every freeze-thaw cycle. We won't apply sealer over unfilled cracks.
For a deeper look at the crack filling process specifically — what can be filled, what can't, and how we handle spider cracking — see our Crack Filling Guide (coming soon).
The short version
Sealcoating is a surface-level protective coating that slows UV damage, water infiltration, and petroleum contamination. It extends the life of asphalt that's in reasonable shape. It doesn't fix structural problems, it doesn't replace crack filling, and it needs to be done on a regular cycle to work. When it's applied correctly — with proper prep and the right method for the surface — it's the most cost-effective form of asphalt maintenance available.