How to repair holes in the AC duct

[jolenemarie]

We are in the middle of a basement remodel and as part of it removed a whole-house humidifier (non-functional). Now we are left with 3 holes in the ducts. A large one where the main unit was located, a round one where the return connected to the humidifier, and an outlet-size hole where the controls used to be. I was wondering how to patch it up. I was thinking getting sheet metal and screws and then sealing it around with foil tape...is this enough? Is there a glue type of material to insure it does not leak? Thanks in advance!

[HayZee518]

the normal way of sealing a large opening is with S cleats sheet metal screws and a piece of 26 ga sheet metal. the S cleat looks like the letter S. one part of it slides on the exposed duct. this is applied on the other two parts of the opening. a piece of sheet metal is cut to fit into the other grooves of the S cleat with a tab that overlaps the duct. the piece is slid into the s cleats and sheet metal screws fasten the last edge to the duct. a foil tape or duct tape can be used over the last joint.

[jolenemarie]

Thanks! Did it exactly as you said and it turned out great. My contractor was really impressed!

[HandymanTrainer]

The first answer was the correct one, however there is one note: the tape you were looking for, which is the stickiest stuff on the planet, and which has thickness and flexibility for such repairs is called Gummy tape, and can be purchased at HVAC supply stores...some really handy tape to have around by the way =)

HandymanTrainer