Duct Sealing in San Gabriel - Leakage Measured, Then Priced in Writing

Fast, Reliable Duct Sealing Across San Gabriel

Duct sealing in San Gabriel typically runs $700 – $1,400 for a whole-home job on a 1950s-era house with original metal ductwork, and most jobs are completed in a single day. The work is straightforward: we find the leaks, clean the surface, and seal every joint and seam so the air you paid to heat or cool stays in the duct instead of leaking into your crawl space. That matters more in San Gabriel than most people realize, because the older homes here have raised foundations with duct runs that have been pulling dusty crawl space air into bedrooms and living rooms for decades.

Call (626) 469-5477

Our crews know the Mission District, the streets around San Gabriel High School, and the tract developments near Dewey Avenue. We arrive inside the quoted window, price is written down before we touch anything, and every job is covered by the 365-Day Done Right Promise. Call (626) 469-5477 for a free estimate and a straight answer on what your ducts actually need.

Why Hollis Air Duct Pasadena Is San Gabriel’s Preferred Duct Sealing Company

San Gabriel homeowners call us because they want to know exactly what’s under their house and what it will cost to fix. That’s the whole job. We don’t do bait pricing, and we don’t quote a low number just to get a van in the driveway. The price we write down before work starts is the price on the invoice. That’s not a slogan; it’s how we’ve operated since 2004, and it’s why the bulk of our San Gabriel work comes from referrals, not coupons.

When we send a technician to San Gabriel, that person is background-checked, uniformed, and accountable to the same standard on every job: arrive inside the window, price in writing, complete the work by the book, and leave the site clean. We call it the Garrison Code, and it applies whether we’re sealing ducts in a 1920s bungalow north of Mission Road or a 1960s ranch off San Gabriel Boulevard. Residents here know that a house this age hides surprises under the floor. Our job is to find them and tell you the truth about what you’re looking at.

If the work fails within a year, we come back and make it right at no charge. That includes a free second visit. We put that in writing on every San Gabriel job, because a warranty you can hold is worth more than a promise you can’t.

Air Duct Sealing in San Gabriel

Air Duct Sealing in San Gabriel is the process of locating and closing every leak, gap, and disconnected joint in the duct system that carries heated and cooled air through your home. In a city where many houses sit on raised foundations with original galvanized steel ducts, that work almost always starts with a camera inspection. We send a scope into the duct runs under the floor to see what’s actually there: crushed sections, pulled-apart joints, old tape that dried and cracked years ago, and sealant peeling away from decades of grease and dust buildup. Sealing without looking first is a good way to miss the leak that’s actually causing the problem.

The reason this matters so much in San Gabriel is that the original ducts in pre-1970 homes were built with rectangular cross-sections and sharp 90-degree elbows. Those sharp turns catch fine grit and pet hair, and when a joint downstream pulls apart, the system starts pulling dusty crawl space air straight into the house. You can clean a duct like that, but if you don’t seal the run, you’ll be back to the same dust issue by the end of summer.

Camera Inspection and Leak Location

Before we apply any sealant, we map the duct runs and identify every leak point. In San Gabriel raised-foundation homes, that often means working in narrow crawl spaces where clearance is measured in inches. We use a camera to see the full run, including sections we can’t physically reach, so we know which joints are open and whether any runs are crushed or disconnected entirely.

Mastic and Retrofit Sealing

We seal with commercial-grade mastic, applied over a properly prepped surface, and reinforced with aluminum tape where the joint geometry calls for it. For ducts we can reach from the crawl space, we’d rather do the work by hand than blast aerosol sealant from inside and hope it lands where it’s needed. Hand-sealing means we can verify the work before we call it done.

Duct Sealing Services in San Gabriel

Duct Sealing Services in San Gabriel cover the full range of what an older home needs: locating disconnected runs under the floor, reconnecting and sealing separated joints, sealing floor registers that have pulled away from the subfloor, and bringing duct runs back to the airflow they had when the system was new. That last part matters, because in older San Gabriel homes we routinely find the airflow to the back bedrooms has dropped off sharply over the years. The cause is usually a joint that pulled apart under the house, not a problem with the HVAC unit itself.

This page targets San Gabriel specifically because the housing stock here is different from what you’d find in newer Valley cities. These homes were framed before modern building codes, the crawl spaces are tight, and the ducts have a lot of years behind them. If you’re noticing a musty smell when the air kicks on, or one room that never seems to get comfortable, the odds are good that your duct system is leaking conditioned air and pulling in air from the crawl space at the same time. That’s a sealing problem, and it’s fixable.

Floor Register Sealing and Replacement

Older San Gabriel homes often have original steel floor registers that were never touched when the carpet came out and went back in. Over the years, the metal register boots pull away from the subfloor, leaving a gap that lets crawl space dust and humidity enter the living space. We seal those boots tight and replace registers that are too far gone to seat properly.

Crawl Space Access and Repair

We physically enter the crawl space whenever clearance allows and work on the ducts directly. In homes where the crawl space is too narrow for a person, we use our camera and specialized tools to reach the accessible sections and seal what can be reached safely. Either way, you get a straight report on what we sealed and what we saw.

Trusted Brands We Service in San Gabriel

We see and service duct systems built around equipment from every major manufacturer, so no brand problem surprises us. Our trucks carry sealing mastic and aluminum tape compatible with original galvanized steel duct runs, plus the tools to work with modern flexible duct and plenum connections. If you have an older Aprilaire filtration unit tied into the system, we’ll work around it and make sure the duct boot connection is sealed properly. We keep supplies from Abatement Technologies and Rotobrush on the truck for San Gabriel jobs, which means we don’t have to leave mid-job to chase parts across the county. It also helps us keep the work to a single visit when we find something unexpected under the house.

Common Duct Sealing Problems We See in San Gabriel Homes

• Sealant peeling off oily galvanized steel. Original ducts in San Gabriel kitchens and utility rooms often have decades of grease and dust baked onto the metal. If sealant goes on over that residue, it peels within months. We clean the surface first, and that prep step is the difference between a seal that lasts and one that fails by next summer.
• Mastic joints cracking as floor joists shift. Raised foundations in San Gabriel expand and contract with the heat. When floor joists move, rigid mastic joints can crack and reopen leaks. We see this constantly in pre-1970 homes, and it’s why we inspect every joint visually after sealing and explain which ones may need a more flexible approach.
• Sealing only the easy sections. Some outfits seal what they can reach from the access hatch and never look deeper. The narrow crawl spaces under San Gabriel homes hide the worst leaks: crushed runs, disconnected branches, and sections that were never connected properly in the first place. We scope the full run before we seal anything.
• Original floor registers never re-seated. After decades of carpet replacements and flooring changes, the register boot under the floor often sits loose against the subfloor. That gap pulls dirty crawl space air into the house whenever the system runs. Sealing the boot is a small job with an outsized effect on the dust levels in your living room.

Pricing for Duct Sealing in San Gabriel, CA

We Also Serve Cities Near San Gabriel

Our crews regularly work Duct Sealing in San Gabriel and the surrounding communities, including Temple City, Alhambra, Rosemead, and Arcadia. The same pricing rules apply no matter which neighborhood we’re in: written price, background-checked crew, and a full year of coverage. If you’re on the edge of San Gabriel and one of the neighboring cities, call us and we’ll tell you straight whether we handle your street.

FAQs About Duct Sealing in San Gabriel