Whole-system duct and dryer vent check with before-and-after photos - you see exactly what came out of your vents
That "$99 whole-house special" is a bait ad - the real number appears once they are in your hallway, or the "clean" is a shop-vac at the register. We photograph the inside of your ducts before and after instead.
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AfterFast, Reliable Duct Sealing Across El Sobrante
We’re the crew Hollis Air Duct Cleaning sends to El Sobrante when a homeowner calls with ducts that whistle, smell like last fall’s smoke, or push heated air into the crawlspace instead of the bedroom. Our San Francisco Bay Area office dispatches teams to the hillside ranches off San Pablo Dam Road and the valley-floor neighborhoods near Appian Way, usually with same-week availability because we keep El Sobrante on our regular route. If your registers blow dust, your energy bill climbed without explanation, or you catch that sharp ash odor every time the furnace kicks on, the problem is often gaps in the duct system itself, not just dirty ducts. Call (361) 326-5060 and we’ll put a camera through the lines, show you what we find, and give you a written price before any sealing work starts.
Why Hollis Air Duct Cleaning Is El Sobrante’s Preferred Duct Sealing Company
We’ve worked on enough El Sobrante homes to know the pattern. The 1950s through 1970s ranch houses in the hillside subdivisions above San Pablo Dam Road were built with galvanized steel trunk ducts that have now had sixty-plus years to rust at the seams. When a 1990s retrofit added flexible duct branches, those transition points were taped, not sealed with mastic. That matters here more than in flatland cities because El Sobrante sits in the smoke path from the Wildcat Canyon fire corridor. A taped joint pulls in attic air during the return cycle, and that attic air carries ash and pollen from the oak and eucalyptus canopy surrounding the valley.
Our Duct Sealing in El Sobrante work is covered by the 365-Day Done Right Promise in writing on every job. If a sealed joint fails or the smoke odor returns within a year, we come back and make it right at no charge, including a free second visit. Roy Castellanos built this standard into the company from the start. Technicians arrive background-checked and uniformed, inside the quoted window, with the price already written down before they touch a tool. Phones are answered by a live person 24 hours a day, seven days a week. No voicemail loops. No callback queues.
Duct Repair in El Sobrante
Duct Repair in El Sobrante usually means fixing the mixed-metal transitions where original galvanized steel meets retrofitted flexible duct, or replacing sections crushed by decades of crawlspace traffic and pest activity. A typical repair job in El Sobrante runs $280 – $620 depending on how many feet of duct need replacement and whether we need to cut access into a finished attic or crawlspace. We always inspect with a camera first so you see the damage before we quote.
Rusted Galvanized Trunk Sections
The original steel ducts in El Sobrante’s hillside ranches corrode from the inside out, especially at longitudinal seams and branch takeoffs. We cut out the failed section and splice in new galvanized or switch to insulated flex where the run allows, then seal with mastic and fiberglass mesh, not tape. Tape fails in the temperature swings of an unconditioned attic.
Crushed Flex Runs Under the House
Crawlspace flex in El Sobrante homes often gets flattened by storage boxes, rodent activity, or a previous contractor who used the wrong diameter. A crushed return duct pulls air from the crawlspace instead of the house, pressurizing the dirt and moisture into your supply. We replace with properly supported flex or rigid pipe where clearance allows.
Air Duct Sealing in El Sobrante
Air Duct Sealing in El Sobrante is the step that makes cleaning last. We seal the full system, from the air handler cabinet and plenum through every trunk, branch, and register boot, using duct mastic rated for the temperature swings of unconditioned spaces. A typical whole-system sealing job in El Sobrante runs $1,400 – $2,800 for a single-story ranch, depending on duct count, attic versus crawlspace access, and whether we need to seal the air handler cabinet and blower motor housing too. We quote by the system, not by the vent, and the price is written before we start.
Mastic Sealing at Transitions
The taped joints where flex meets steel are the weakest point in most El Sobrante duct systems. We remove old tape, clean the metal, and brush on mastic in two coats with embedded mesh at stress points. The seal is permanent, flexible, and rated for the heat cycling that destroys tape adhesive in two to three seasons.
Static Pressure Verification
After sealing, we measure static pressure at the air handler with a digital manometer. If the system was leaking 20% of its air into the attic, the pressure reading jumps after sealing, and we can show you the before-and-after numbers. That verification is part of every El Sobrante job.
Trusted Brands We Service in El Sobrante
We stock sealing supplies and filtration components from Honeywell, Aprilaire, and Abatement Technologies for El Sobrante jobs, which means most repairs don’t wait on parts orders. Honeywell media air cleaners and Aprilaire whole-house filters integrate with the sealed system to catch the fine ash particles that slip past standard fiberglass filters during wildfire season. Abatement Technologies HEPA negative-air machines are what we run during agitation cleaning to keep your home under containment while we work. When a sealing job calls for upgraded filtration, we size it to the system’s new static pressure, not guess at the filter rack dimensions.
Common Duct Sealing Problems We See in El Sobrante Homes
- Smoke intrusion at rusted galvanized joints. The original steel ducts in 1960s hillside ranches have pinhole rust at seams that standard brushing never reaches. We find these with a borescope camera, then seal or replace the section so Wildcat Canyon smoke stops cycling back into your supply air.
- Disconnected flex retrofits in crawlspaces. The 1990s flex additions under El Sobrante homes often pull loose at the boot or sag onto the dirt, creating a return path for crawlspace air. We re-support, reconnect, and seal with mastic so the system breathes house air, not soil air.
- Leaky air handler cabinets pulling attic smoke. The sheet-metal cabinet around your furnace or air handler has seams and filter slots that are rarely sealed by the original installer. We gasket and mastic these so the supply side doesn’t draw unfiltered attic air during the heating cycle.
- Crushed or kinked branch ducts in finished attics. El Sobrante’s older ranches with bonus-room conversions often have ducts buried under insulation and foot traffic. We expose, repair, and seal these runs so conditioned air reaches the rooms that need it.
Pricing for Duct Sealing in El Sobrante, CA
A typical duct sealing job in El Sobrante runs $1,400 – $2,800 for a complete single-story system, with partial sealing of problem zones starting around $680 – $1,100. Duct repair work, where we replace crushed or rusted sections, usually falls between $280 – $620 per repair zone. What moves the price: how many duct runs serve the house, whether the ducts are in an accessible crawlspace or a finished attic, and whether the air handler cabinet and plenum need sealing too. We do not quote by the vent. We quote by the system, one flat price agreed in writing before any work begins. Every estimate is free, and we show you camera footage of the leaks so you understand what you’re paying for. Call (361) 326-5060 to schedule.
We Also Serve Cities Near El Sobrante
Our crews work the full San Pablo Valley corridor, including El Sobrante, Pinole, San Pablo, Hercules, and El Cerrito. The same 365-Day Done Right Promise, the same written pricing, and the same live-answer scheduling apply whether we’re sealing ducts in a Pinole split-level or a Hercules hillside home.
Serving El Sobrante, CA - Our Local Coverage Area
We’re based in the El Sobrante area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About Duct Sealing in El Sobrante
Because cleaning removes loose debris but doesn’t seal the gaps that pull new smoke into the system. In El Sobrante, we often find rusted galvanized-to-flex transitions and unsealed air handler cabinets that draw attic air during the return cycle, and that attic air carries Wildcat Canyon ash. Sealing those leaks stops the odor source. Call (361) 326-5060 for a camera inspection and written quote.
We inspect with a borescope camera first to map rust, separation, and failed seams. Where the steel is structurally sound, we seal with mastic and mesh. Where it has rusted through, we cut out the failed section and splice in new duct, then seal the transition. We show you the camera footage before we quote.
Yes, by a meaningful amount. Sealing the return side of your duct system prevents it from pulling unfiltered crawlspace or attic air that carries tree pollen into the supply. For El Sobrante homes surrounded by oak woodlands and eucalyptus groves, we often pair sealing with a properly sized Aprilaire or Honeywell media filter to catch what remains.
We access the crawlspace, inspect every trunk, branch, and boot with a camera, then seal all joints with mastic rated for damp conditions. We re-support sagging flex, replace crushed sections, and verify that the return duct isn’t drawing soil air. The work typically takes four to six hours for a single-story ranch.
We seal the full system, including the air handler cabinet, plenum, and filter slot, because unsealed cabinets are a major leak point that re-contaminates the supply side. The 365-Day Done Right Promise covers all sealed components, and we verify static pressure improvement before we leave.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving El Sobrante and the San Francisco Bay Area since 2004.