Air Duct Replacement in Elk Grove, CA

When is replacing duct better than patching it?

Go into the attic with a flashlight. Look at the collar, not the middle. A flex run that slipped off the takeoff hangs loose. You will see insulation dragged toward the opening. That run is now a return from the attic. Tape will not hold it twice. Reattach with a draw band and mastic, or replace.

Check the inner liner by squeezing the flex. If it crunches, the mylar is cracked. Cracked liner leaks through the jacket anyway. Patching the jacket hides the real hole.

Under older raised-floor houses, duct is sheet metal with cloth tape. The adhesive dried out decades ago. Tape hangs in strips at every joint. Crawlspace rodent traffic is common here. Nesting material and urine odor ride the supply air. Cleaning a fouled galvanized run is defensible. Cleaning a fouled flex run is not. The liner holds the smell.

Fiberglass ductboard is the clearest replace case. Press the interior face. If it fuzzes or dents, it is shedding. Brushes accelerate that.

Open duct is also your chance at the return. Many hallway returns here are a single grille with a gapped filter frame. Garage-wall returns pull whatever is parked inside. Fix both while the plenum is open.