Air Duct Replacement in Los Gatos, CA

When is replacing duct worth more than patching it?

Patching makes sense for one disconnected boot. Replacement makes sense when the failure is everywhere. On 1950s-70s galvanized trunk and round branch runs, the sheet metal often outlives the fiberglass wrap and the cloth-tape joints. Tape turns brittle and powdery. Re-taping a dozen dried joints buys a season, maybe two.

Pre-1975 plenums get treated carefully. Some carry asbestos-containing tape. That is not something to tear out and bag. Suspect material is left alone and tested. A licensed abatement contractor handles it before any demolition begins.

Flex duct from the 1980s through 2000s fails differently. R-4.2 and R-6 runs sag into long bellies between joists. Turns get crushed against rafters. Replacement is worth doing mostly because it lets the geometry be rebuilt. Proper support strapping and wider radius bends go in. Mastic goes at every boot and collar, not just tape.

The return side decides the result. Many Los Gatos ranch tracts have one undersized central return pulling attic and wall-cavity air past a leaky filter rack. New supply duct will not fix that. Crawlspace runs under raised foundations in older downtown and foothill homes add their own problem: winter condensation on cold supply lines, plus rodent nesting that no amount of sealing undoes.