Residential roofs should be inspected regularly by experienced roofing contractors to ensure that no leaks, weak spots or missing shingles exist that could cause structural damage to the home. When roofs are not properly maintained, water leaks can occur that are not easily detectable, especially when they do not cause visible water stains on ceilings. Moisture accumulating unnoticed within your home's walls, attics and crawlspaces will facilitate growth of molds, fungi and bacteria potentially harmful to you and your family's health.