Duct Sealing in El Dorado Hills, CA

What duct sealing actually involves here

Homeowners check the register first. Wrong place. Pull the grille and look at the boot's edge against the drywall. Daylight-colored dust streaks mean air is moving through that gap. Then feel the ceiling nearby on a hot afternoon. A warm halo means attic air is getting in.

Flex duct fails two ways. The inner liner slides off the metal collar, leaving the gray jacket intact and innocent-looking. Or a stored box, a cable installer's knee, or settled insulation pinches a run flat. Pinched flex gets replaced. Mastic on a crushed run does nothing.

Return side matters more than supply. A leaky panned joist return or an unsealed platform under the air handler pulls attic air. That means insulation fiber, drywall dust, and whatever rodents left behind. It loads the filter fast and coats the evaporator coil. People blame the filter brand.

We brush mastic, not tape. Fiberglass mesh bridges anything wider than a pencil. Flex gets a band on the core and a second on the jacket, both seated on the collar bead. Mastic cures before any retest.

Attic work goes early. Afternoon attic heat is a safety limit, not a preference. Scheduling bends around it.