Duct Sealing in Houston, TX

Duct sealing in Houston homes

One room never cools. The attic feels oddly cool near the air handler. Dust returns a week after cleaning. Those three symptoms usually point to the same thing. Conditioned air is leaving the duct before it reaches the register. Slipped boot collars are the common culprit. The flex pulls off the metal sleeve and dumps supply air into the attic.

Sealing method depends on what is up there. Pre-1960 galvanized trunks with branch takeoffs need mastic on every seam and takeoff collar. Ductboard plenums from the 1960s through the 80s often fail at the corner joints. Insulated flex from the 80s onward fails at the inner core connection, not the outer jacket. Tape alone does not hold in a Houston attic. Heat and humidity cook the adhesive loose.

The return side matters more than most people expect. Unsealed return plenums and wall-cavity returns pull attic fiberglass, cellulose, insect frass and gypsum dust straight to the blower. Seal that first. You will see it on the filter.

Sealing is not always the answer. Sagging flex kinked between joists needs resupport or replacement. Crushed runs stay crushed. Under-slab ducts in some 1950s and 60s slab builds may hold silt and moisture, and sealing them does not fix that.