Some of the early warning signs of needing a new roof are leaks, warped or stained ceiling tiles or drywall, and a musty odor from mold. When water penetrates the roof, it can cause toxic mold to grow in insulation, drywall, and ceiling tiles. Mold can cause chronic asthma and respiratory infection. Roof leaks can also cause paint to peel on walls, doors, and ceilings. Another sign that your roof may need replacement are drafts, presence of bacteria and mildew, and heat or cool air loss from the home. A new roof should be well insulated to keep the AC-cooled air inside during hot summer months, and keep the heat inside during winter months. A new roof should have a waterproof leak barrier, called decking, that prevents the intrusion of moisture.