Q: We snapped a chalkline in the wrong place on a concrete driveway before sawing joints. We've tried pressure washing and scrubbing, but can't remove the stain. Is there any other way to get rid of the unwanted line?
A.: Two chalk manufacturers print the same information on chalk bottles. "Warning: Red, yellow, and fluorescent chalks are permanent colors. There is no known way to remove them. Blue chalk may also be permanent on porous materials." A lumber-crayon manufacturer said that sun and acid rain might eventually lighten the stain.
In a November 1997 Problem Clinic item (p. 928), a contractor wants to know how to remove unwanted chalk lines from a concrete driveway. My theory is "if you can't kill the bull, you best run the other way." Since the errant chalk line can't be removed, I suggest adding more lines to create a design. An architect could sketch an interesting and unique design based on the "less is more" concept, using a few strategically placed lines. Then the chalk lines won't look like a mistake, and the sun will eventually fade them. Also, this fix can be cost-effective. (But you may want to hire someone to place the lines.)
-David A. Branch, Henry Tyler Construction Corp., Birmingham, Ala.