How to Fix Squeaky Air Ducts in Floors

Go into the basement of the structure and pay attention to how the ductwork runs along the ceiling. Note the location of each brace -- these are small metallic dividers that create the ductwork’s segmented appearance. Inspect each brace by working from one wall to the next. Use a stepladder to gain better access to the braces if need be and a flashlight for harder to see places.

Locate any brace that’s loose by gently shaking the ducting on either side of the brace. If you hear the slightest squeak, apply a small amount of spray-on lubricant to the joint between the brace, then tighten the holding screws. For additional stability, apply a small bead of silicone sealant along the joint between the bracing and the duct.

Choose a flattened area of ductwork about midway between each brace on each section of ducting should you not be able to immediately ascertain the origin of the squeaking noise. Press a broom handle upward into the flattened area to create an intentional dent that takes up “slack” in the metal, making it more rigid and less likely to squeak when the furnace or central air unit starts or completes a cycle.