How to Fix the Condensation in a Bathroom Vent Tube

Written by g.k. bayne
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How to Fix the Condensation in a Bathroom Vent Tube
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Bathroom ventilation fans remove warm, moist air from the room. The vent pipe or tube then takes this moist air from the bathroom and exhausts it to the outdoors. During cooler or cold weather, condensation often forms on the inside of the tube. This condensation is formed when the air surrounding the vent tube is cooler than the air inside the pipe. Applying an insulation jacket around the pipe will prevent the condensation from dripping back into the home.

Skill level:

Things you need

  • Pipe insulation jacket
  • Plastic ties
  • Scissors

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  1. 1

    Gain access to the attic area of your home where the ventilation tube runs from the bathroom and through the roof or exterior wall.

  2. 2

    Wrap the vent tube in the correct diameter pipe insulation. Most ventilation tubes are either 4 inches or 6 inches in diameter. Smaller vent tubes may be used as well.

  3. 3

    Begin wrapping the tube at the top of the pipe or at the furthest point from the fan. Secure the insulation in place with a plastic tie. Attach a tie every 6 inches along the length of insulation.

  4. 4

    Fit the insulation as close as possible to the upper roof decking or exterior wall and down around the exhaust tube coming from the bathroom ventilation fan. Cut the insulation to length, when you reach the fan, using scissors. The overall goal is to cover every portion of the exposed vent tube with insulation.

Tips and warnings

  • You can use a can of spray foam to cover the bare pipe. The foam can be extremely messy when it exits the can. Use the entire can at once, as the foam will quickly set up and clog the delivery tube from the spray can.

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