Terms of the Trade: What Is a Chalk Line?
Since the time of ancient Egypt, chalk lines have been used in construction for marking long, straight lines on flat surfaces. The chalk-coated string, housed inside a casing, is pulled to the needed length, held taut at both ends and snapped against the surface. The snapping motion transfers the chalk from the string to the surface that’s being marked, which could be anything from lumber to concrete. The chalk can then be wiped away after it serves its measuring purpose.