How long should the sealant around plenums / ducts last before developing air leaks? By sealant, I mean the white substance that seems almost like plumber's putty, but not as flexible.
I'm asking because I have a new home with HVAC ductwork that has been installed for about four months and I can now feel small airflow leaks in the ductwork above the plenum. This system supposedly passed a "smoke" test when installed. I'm trying to decide if this is a reasonable "call for a warranty" repair, or if it is normal homeowner maintenance.