The answer to 'roof decking ice dam' is that ice dams form when melting snow refreezes at the roof's edge, trapping water and causing it to back up under the shingles and into the roof decking. This can lead to water damage, mold, and structural problems if not addressed.
Common causes include poor attic insulation, inadequate ventilation, and heavy snow buildup. Symptoms include icicles at the roof's edge, water stains on interior ceilings and walls, and soft or spongy roof decking. Solutions may include improving insulation and ventilation, removing snow buildup, and installing heating cables or other ice dam prevention systems. However, significant ice dam issues often require professional roof repair services to properly address the underlying problems.