tack coat

tack coat

[′tak ‚kōt] (civil engineering) A thin layer of bitumen, road tar, or emulsion laid on a road to enhance adhesion of the course above it.

asphalt tack coat

asphalt shingles: above, an asphalt shingle strip; below, installing asphalt shingles A light coating of liquid asphalt on an existing asphalt surface or on a portland cement concrete surface; used to ensure a bond between the old surface and the overlaying course.