Moisture, mold & pests

Mold growing in a closet

Closets often have poor airflow against an exterior wall, which lets humidity condense and mold grow on walls, shoes, or stored items without being noticed right away.

Difficulty
Easy
Time
1–2 hours
DIY cost
$15–$40
Pro cost
$300–$1500 if a leak needs repair

Symptoms

  • Musty smell when opening the closet door
  • Visible spots on the wall, floor, or stored items
  • Items feel damp or have a white or dark film

Likely causes

  • CommonPoor air circulation behind clothes or stored boxesA closed, packed closet traps humid air against the wall with nowhere to go.
  • CommonCloset located on a cold exterior wallCold exterior walls encourage condensation, especially in closets that stay closed most of the time.
  • PossibleNearby leak, such as from a roof or an adjacent bathroom wallA shared wall with a bathroom or an upstairs leak can feed moisture into a closet from behind.

What to do

  1. Remove all items from the closet and inspect the walls, floor, and baseboards closely for mold or dampness.
  2. Check any affected clothing, shoes, or boxes and clean, dry, or discard heavily affected porous items.
  3. Clean visible mold on hard surfaces with a mold-specific cleaner, then let the space dry completely before restocking.
  4. Leave the closet door open periodically and consider a small fan or moisture-absorbing product to improve airflow.
  5. Avoid packing the closet too tightly against exterior walls to allow some air movement.
  6. Check the exterior side of that wall for a nearby leak source if the closet backs onto a bathroom, roof line, or plumbing.
  7. Consider adding closet ventilation, like louvered doors, if the problem recurs regularly.

Tools and parts

  • Gloves
  • Cleaning cloths
  • Small fan
Mold cleanerSearch: “mold and mildew cleaner”
Moisture absorberSearch: “closet moisture absorber”

When to call a pro

Call a mold remediation specialist for extensive growth, and a plumber or roofer if a leak is feeding the closet.

Safety

Use caution

Wear gloves and a mask when handling moldy items, and wash hands after cleanup.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.