What a Fog Seal Is on Asphalt

A fog seal is a light spray of diluted asphalt emulsion on existing pavement, quoted in gallons per square yard. It is not a thick driveway sealer from a bucket. Too heavy a rate turns the surface slick. It does not fill potholes or add structure.

Open free asphalt tonnage calculator →

A light spray, not a new layer

A fog seal is a light spray of diluted asphalt emulsion on pavement that is already in place. Crews use it to darken a dry, oxidized surface and to hold a little loose fines. It is measured in gallons per square yard. Quotes often land from a few hundredths of a gallon per square yard up to a couple of tenths, depending on dilution and how tight the surface is. That range is how you read a bid line. It is not a home spraying recipe, and it is not permission to coat a driveway with a garden sprayer. The work belongs to a crew that can control the rate. Peaks of the stone should still show when they are done.

How to read the rate on a quote

If a quote says 0.05 gallon per square yard or 0.10, ask what dilution that number assumes and whether the surface is tight or open. A tight mat takes less. An open mat can take more and still leave texture. A few hundredths and a couple of tenths are far apart in film thickness, so two fog quotes are not the same job just because both say fog. Ask them to point at the rate and the dilution in writing. Too much emulsion fills the texture tires grip and leaves a slick face, especially on a slope. You are checking the bid, not learning to spray hot binder or emulsion yourself.

What a fog seal leaves undone

A fog seal does not fill potholes, does not bridge cracks that move, and does not add structural thickness you can count as inches of hot mix. A driveway that has lost its base still needs a base repair or a new section. The fog is a preservation coat on sound pavement. It is also not the thick driveway sealer people brush from a bucket. Those products sit heavier on the surface and are sold as a different system. If the quote mixes the words fog and sealcoat, ask which system, which rate, and what the surface will look like when stone peaks still show. Keep cars off it until the crew says the emulsion has cured.

A practical sequence

Read a fog seal as a light diluted emulsion spray, quoted in gallons per square yard.
Ask what dilution and rate the bid assumes for your surface.
Expect stone peaks to remain visible when the rate is light enough.
Plan a separate repair if the pavement has potholes or a failed base.

The mistake to skip

Reading a fog seal rate as a do it yourself spraying recipe, or expecting it to rebuild the driveway.

Questions people ask

How much emulsion is a fog seal?

Quotes are in gallons per square yard, often from a few hundredths up to a couple of tenths, depending on dilution and how tight the surface is. Ask the bidder to state the rate and the dilution. That number explains the quote. It is not a home spraying guide. Stone peaks should still show so the surface keeps texture.

Will a fog seal fill potholes?

It is a light film on existing pavement. It does not fill potholes or add inches of structure. A failed base needs a different repair. Fog seal is also not the thicker driveway sealer sold in a bucket. Ask which product the quote actually includes, and keep traffic off until the crew says it has cured.

As an Amazon Associate, AsphaltTons.com earns from qualifying purchases. Product links below are sponsored.