Duct Tape Failure

• Duct tape is best suited for flat surfaces that are not exposed to heat or weather elements. It is also not suited for weight-bearing repairs. When exposed to heat, duct tape will become soft and anything it is holding will sag, including vent pipes. Over a long period, duct tape will also dry-rot and leave nothing but threads.
  
  

Foil-Faced Duct Tape

• One type of duct tape, known as foil-faced tape, is designed specifically for vent pipes. Foil tape will not fail and it provides a tight seal between pipe sections or seams. This tape is available at heating and cooling stores or at most home remodeling centers that sell vent pipes.
  
  

Fittings

• If your vent pipe also has fittings such as elbows that allow your pipe to be situated where it needs to go, use foil-faced duct tape and clamps. Vent pipe clamps will keep your fittings from sliding off your pipes, and the tape will provide added security.
  
  

Application

• To apply foil-faced duct tape to your vent pipes, simply stick the end of the roll to the pipe and start winding tightly around the pipe, or cut three 7-inch strips to wrap around the pipe. It should not take any more tape than that to provide a good seal.