Look for the following plumbing problems in attics:

  1. Damaged plumbing vent pipes;
  2. Stack vents terminating in the attic.
  3. Plumbing vent slopes less than 1/4-inch per foot;
  4. Un-insulated water supply pipes;
  5. Plumbing stack 3" minimum diameter at roof (cold climate only); or
  6. Plumbing vent diameter reduction located less than 12" from sheathing (cold climate only).