While most hairline cracks aren’t terribly serious, they do cause many people to be concerned. If you notice a larger crack, you’ll want to consult a professional to investigate, determine the root cause, and identify the proper solution. Keep in mind, behind the stucco is a waterproof membrane, so not every crack is allowing water into your property. In most cases the crack could be superficially in the finish material or in the Brown Coat only. That’s why so many people are choosing Elastomeric Finishes that will, in most cases, bridge the crack.