"Sealing" a driveway can mean several different things, and the wrong one on the wrong surface is money wasted. Here's a plain-English breakdown of chip seal, sealcoating, slurry seal and fog seal — and which one actually works if what you have is gravel.
Quick answer: sealcoating, slurry seal and fog seal are all thin treatments for existing asphalt. Chip seal is the one that also goes over a compacted gravel driveway, because it builds a bonded stone surface rather than just coating one.
| Treatment | What it is | Goes over |
|---|---|---|
| Chip seal (tar & chip) | Hot binder sprayed on the surface, then crushed stone spread and rolled in to lock it down | Compacted gravel or sound asphalt |
| Sealcoating | A thin liquid protective coating brushed or sprayed onto pavement | Existing asphalt |
| Slurry seal | A thin mixture of asphalt emulsion, fine stone and filler spread as a surface layer | Existing asphalt |
| Fog seal | A light spray of diluted asphalt emulsion, with no stone added | Existing asphalt |
Sealcoating — protection for asphalt, not a new surface
Sealcoating is a thin coating applied to asphalt to help protect it from sun, water and oil. It's maintenance for a pavement that's already in good shape. It doesn't add a wearing surface, and it isn't meant for gravel: a liquid coating has nothing solid to bond to on loose stone.
Slurry seal and fog seal — the road-crew cousins
Slurry seal and fog seal are treatments you'll hear about on public roads. Both are used to refresh asphalt pavement. Fog seal is a light spray of emulsion that helps seal and renew an aging surface; slurry seal adds a thin layer with fine stone in it. Neither one turns a gravel driveway into a paved one.
Chip seal — the one that builds a surface
Chip seal is different because it builds the surface: binder goes down, crushed stone is embedded in it, and rolling locks it together. That's why it's the option that works on a well-compacted gravel driveway — the gravel is the base and the chip seal is the wearing surface. It also goes over sound asphalt. More on which surfaces qualify in chip sealing over an existing driveway.
So which one do you need?
- You have gravel: chip seal. See chip seal vs. gravel.
- You have sound, newer asphalt and want to protect it: a maintenance treatment like sealcoating may be all it needs.
- You have tired, worn asphalt: chip seal is a proven way to resurface it — see chip seal vs. asphalt.
Not sure what your driveway needs? Send us a request and we'll look at it in person. We give free on-site estimates across Murphy and the surrounding NC/GA/TN communities. Request yours here.