Effective attic ventilation is critical for a long-lasting roof. Safeguard your attic possessions against mildew damage. Guard against ice damming in harsh winter climates. Promote your home's energy efficiency. Remove excess heat and moisture to protect your roof from premature deterioration. Avoid roof rot in your attic or roof deck. Minimize peeling and extend the life of exterior and interior paint. Limit the growth of harmful mold.