Fixing a Leaking Air Duct

Fix a Leaking Air Duct

A home\’s air duct system is a very important part in keeping your house safe, and energy efficient at the same time. From time to time, testing should be done on the air duct to confirm that it is not leaking or broken as this can cause damages to the home or building it is in. Air ducts leakage brings problems to our home as they can cause issues in temperature and costs us a lot of money as well. A leaking duct will prevent more air going through to your space for cooling and it takes a longer time to run to meet its temperature requirement. You could fix the leakage of your air duct systems if you have the access to your ducts. Here are the steps.

You will need:

  1. Mastic sealant
  2. Paintbrush
  3. Pliers
  4. Caulk mastic
  5. Putty knife
  6. Duct tape
  7. Panduit strips
  8. Fab mesh
  9. Caulk gun
  10. Foil tape


  1. First, switch on the thermostat rather than turning it in auto mode. To examine the duct work, feel around all connections and joints to look for loose connections and leaks. Overtime, flexible ducts can tear little by little or come unfastened but don\’t worry, you still can repair them.
  2. Then, start with the loose flex connections for the flexible duct reparation. Remove the old Panduit strip if it has fallen off entirely. Remove another layer on the outer layer as well.
  3. Pull the insulation and the inner layer back to unearth 8 to 12 inches of inner layer. Place the inner layer into the boot connection and set it to place with a duct tape.
  4. Use a plier to attach the new Panduit strip by pulling the outer layer down and attaching the strip to it. Do the same step on the outer layer.
  5. Paint the connection with mastic sealant using a paintbrush.
  6. If you found torn flexible ducts, clean them first before drawing the rip together. Hold it in place using a duct tape.
  7. Extend a piece of fab mesh over the seam and paint it with a mastic sealant generously. Let it cure for about 10 minutes. If the seams are too hard to comply, you can use a staple gun to secure them in place. Before you start to apply fab and mastic sealant, make sure to fill the large gaps with insulation first.
  8. Wait for awhile before testing out the unit. Turn it on again to check if you solve the leaking issue. If you feel nothing coming out from the patched spots then you have done the job perfectly. To seal the heat ducts, turn off the HVAC power. Caulk the seams and joints duct work with caulk mastic. Cover them adequately using a putty knife. Use foil tape for areas that you cannot spread the caulk into. Let it cure according to the caulk instruction before turning on your HVAC unit.

If you still feel that you are not able or can\’t get to fix your leaking air duct then it is better to get someone professional or at least, experienced to help you out on this.

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