Air Duct Mold Removal in El Dorado Hills, CA

Air duct mold removal in El Dorado Hills homes

Most duct mold we find here starts in a crawlspace, not an attic. Postwar valley-floor ranches run metal duct under the floor. Humid ground air meets cold summer supply metal. Condensation forms on the outside, then wicks into seams and insulation. Older runs with original internal fiberglass liner are worse. That liner holds moisture and feeds growth once it starts shedding.

The second common source is the air handler itself. A plugged condensate drain or a sweating coil wets the plenum below it. Growth spreads downstream from there. Fiberglass duct board plenums from the 1960s-80s era are porous. You cannot scrub a colonized duct board face clean. That section gets cut out and rebuilt, not fogged.

Plenty of dark streaking at registers is not mold at all. It is dust shadowing from air leaking past the grille, or soot from candles and a woodstove. Rodent nesting in older crawlspace duct smells musty too. We want to see what it actually is before anyone treats it.

Cleaning without stopping the water is wasted work. If the drain pan backs up or the crawlspace has a vapor problem, we say so and that gets fixed first.