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How To Reduce Basement Condensation


Condensation in your basement can pose a significant threat to items you have stored down there. Books, photos and other paper goods absorb the moisture, causing irreversible damage. Metal objects start rusting. Furniture, carpeting and clothing shows signs of mold and mildew.

Condensation occurs when moisture-laden warm air strikes a cold, dry surface, such as a basement wall or window. A similar thing happens with cold water passing through copper pipes. Fortunately, minor condensation issues can be reduced substantially with a few inexpensive precautions.

Difficulty: Easy
Time Required: 1 hour to several days, depending on which steps you take


  1. Wrap the Pipes

    You may already have foam insulation covering the hot-water pipes to conserve energy. Do the same thing on the cold-water pipes and you will take a big step in controlling condensation.

    Buy foam sleeves sized to fit your pipe’s diameter (1/2-inch is typical). Slip the sleeves over the pipes. Cut the foam with scissors or a utility knife, making miter cuts at the corners. For maximum protection, wrap tape around all joints and gaps.

  2. Seal the Ducts

    The ducts in a forced-air heating and cooling system frequently leak conditioned air, which both wastes your money and creates the opportunity for moisture to escape. The humidifiers on central air conditioners can be particularly troublesome in this regard.

    All joints and holes in metal ductwork should be sealed. Use special duct mastic or sealant (not duct tape!) to create a long-lasting and airtight seal.

  3. Add Insulation

    You can reduce condensation by making cold surfaces warmer. Air sealing and vapor retardants keep warm, moist air from passing through building materials. Insulating basement walls can significantly reduce condensation problems.

  4. Provide Ventilation

    For occasional condensation problems, the easiest solution may be to open a window or door from time to time to encourage air circulation.

  5. Use a Dehumidifier

    Dehumidifiers don’t stop condensation from developing; they simply remove the moisture once it occurs. Though not a cure-all solution for major problems, a good dehumidifier can take the edge off of basement humidity.

What You Need

  • Foam pipe-insulation sleeves
  • Duct mastic or sealant
  • Wall insulation, vapor retardant, weatherstripping
  • Dehumidifier

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