Air Duct Repair in San Mateo, CA

Air duct repair in San Mateo homes

One room never gets warm. The register breathes weakly, or smells like crawlspace. That usually means a duct came apart, not a furnace problem. Under 1940s–60s ranches here, the original galvanized trunk-and-branch sits on dirt. Straps rust. Joints work loose. Flex in attics sags between supports and the boot connection pulls free. Then the system heats the crawlspace and pulls rodent debris and loose insulation into your air.

Repair starts with finding the break, not guessing. We trace runs by hand and by airflow at each register. Painted-over registers and boots sealed during a remodel show up often in remodeled older homes. Gravity-furnace conversions are their own category: oversized old trunks reused for a modern blower, with a return system too small for what it now moves. That causes static pressure problems and dust bypassing the filter edges.

Fixes vary by material. Metal gets mechanically fastened and mastic-sealed. It gets re-supported too. Failed flex gets replaced at the boot with a proper collar and inner-liner clamp, not tape. Uninsulated metal in a damp crawlspace condenses during winter fog and grows mold on settled dust, so insulation is part of the repair.

Shoreline homes near the Bay show salt corrosion on sheet metal. Badly pitted sections are replaced, not patched.