A cosmetic crack is a shallow, hairline crack limited to the surface finish, stucco, parging, or a single mortar joint that doesn't affect the structure's ability to carry load and generally stays the same size instead of widening over time.
Cosmetic cracks come from normal shrinkage as mortar or parging cures, minor thermal expansion and contraction between seasons, or small surface stresses that never reach the structural elements underneath. The way to tell a cosmetic crack from something more serious is to watch it: a cosmetic crack stays hairline-thin and doesn't grow, doesn't step across multiple mortar joints, and doesn't show up mirrored on the opposite face of the wall.
Even a cosmetic crack is worth sealing rather than ignoring, though, because a hairline opening in mortar or parging is still a place for water to get in, and once winter freeze-thaw cycles get hold of that water, a crack that started out purely cosmetic can turn into a real repair. When in doubt, it's worth having someone look at it before assuming it's harmless.
More masonry vocabulary from the glossary.
The services where this term comes up.
Chelo's Brick & Stone serves Hillsville, Galax, Wytheville, Fancy Gap, and Independence, VA. Call for a straight answer and a free on-site estimate.
