We took out our old wood stove and replaced it with a brand new one. The old one had eight inch pipe. New one had six inch so we put one piece that went from six on the stove to the eight inch pipe. We replaced all of the pipe too. The only part that is old is the insulated pipe that is in the roof. All else is new. So we put the new pipe up through the roof (and insulated pipe) just like it was and now we have creosote dripping down the outside of the pipe. What could be causing it to drip down the OUTSIDE of the pipe? What do we need to do to fix this?