Fast, Reliable Duct Repair & Sealing Across San Fernando
Most duct repair calls we get from San Fernando aren’t about new damage. They’re about old damage that finally caught up. In a city where the 1971 Sylmar earthquake shifted joints in thousands of post-WWII homes, and where attic temperatures regularly climb past 150°F in July, duct systems here fail differently than they do elsewhere in the Valley. We’re Bellows Air Duct & Vent Co., and we’ve been driving to San Fernando since 1984. From the older blocks along Maclay Avenue to the Hubbard Street corridor, our Duct Repair & Sealing crew knows what to look for in these houses: the tape that dried out, the mastic that cracked, the galvanized metal that’s been shedding debris into your air for decades. We answer calls 24 hours a day. If you’re in 91340 or 91341 and your ducts are leaking, noisy, or pushing dust, call (844) 685-6342. We’ll show you exactly what’s wrong before we quote a price.
Why Bellows Air Duct & Vent Co. Is San Fernando’s Preferred Duct Repair & Sealing Company
We’ve worked on San Fernando homes long enough to recognize the patterns. The post-WWII tract houses packed into this 2.4-square-mile city often still run original ductwork from the 1950s and 1960s. That matters because duct repair here isn’t just sealing a joint; it’s understanding how seismic shifts, decades of heat cycling, and the Valley’s particulate load have compounded the damage.
Our customers in San Fernando tend to be longtime homeowners or multigenerational renters. They’ve lived through enough contractor visits to know the difference between a quick patch and a proper fix. That’s why our 90-Day Done Right Promise is stamped on every job: if it’s not right, we make it right, no paperwork, no arguing. Camera inspection before and after every repair means you see what we see, not just take our word for it.
Calls to our office are answered by a live person, 24/7. Most San Fernando repairs are completed in a single visit by background-checked, uniformed technicians. And the price we quote on the phone is the price on the invoice. No bait coupons, no changes at the door.
We also know the local urgency. When it’s 102°F in San Fernando and your attic ducts are leaking 30% of your cooled air into the rafters, you don’t want an appointment next week. You want someone who knows the difference between Hubbard Street and Maclay Avenue and can be there today.
Our Duct Repair & Sealing Services in San Fernando
Mastic Sealant Application
On a job along the Hubbard Street corridor, our crew found a 1950s metal duct system where joints had shifted during the 1971 quake. The homeowner’s utility bills were climbing because the ducts had been taped with standard tape that failed, causing a 30% air loss. We sealed all joints with mastic and added insulation to bring the system back to efficiency. Mastic is the only proper sealant for San Fernando’s conditions. It stays flexible at 150°F attic temperatures, bonds to metal and duct board, and lasts decades. Duct tape fails here in three to five years. We apply mastic by hand to every joint, seam, and penetration, then verify the seal with a pressure test and camera inspection.
Metal Duct Repair
San Fernando’s housing stock is dense with galvanized metal ductwork from the 1940s through 1960s. The original fiberglass lining inside these ducts degrades over time, shedding particles into your airstream. We’ve found sections where the lining has collapsed entirely, blocking airflow and forcing your HVAC system to work harder. Our metal duct repair service removes damaged lining, repairs or replaces corroded sections, and restores proper airflow. In some cases, partial replacement with modern duct board makes more sense than trying to salvage sixty-year-old metal. We show you the camera footage and explain both options with upfront pricing before any cutting begins.
Flex Duct Repair and Replacement
Later retrofits and additions in San Fernando often used flex duct, which works fine when properly supported. But tight attic spaces, especially near seismic retrofitting beams added after 1971, create kinks and tears that choke airflow and leak conditioned air. We’ve replaced crushed flex runs in attics where a beam installation left barely enough clearance to crawl. Our flex duct repairs use properly sized, insulated replacement runs with adequate support straps so they don’t sag or kink again.
Duct Insulation
Uninsulated or poorly insulated ductwork in San Fernando is a double penalty. You’re losing cooled air to 150°F attic temperatures in summer, and in winter those same attics drop cold enough to condense moisture on duct surfaces. We install proper duct insulation, typically R-6 or R-8 fiberglass wrap with a vapor barrier, sealed at all seams with mastic. For homes near the I-5 corridor, where diesel particulate load is heavier, insulation also helps maintain cleaner interior duct surfaces by reducing temperature differentials that draw attic dust into the system.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in San Fernando
We carry professional-grade equipment and materials from the brands that serious HVAC contractors specify. For duct repair and sealing work in San Fernando, we stock mastic compounds and application tools from Abatement Technologies, along with inspection cameras and HEPA containment from Nikro and Rotobrush. These aren’t consumer-grade products from the hardware store. They’re the same materials we’d use on a commercial job, and we keep them on every truck so we’re not making a second trip while your attic sits open. That matters in San Fernando, where a single visit is usually all it takes to complete the repair.
Common Duct Repair & Sealing Problems We See in San Fernando Homes
- Failed earthquake patches. The 1971 Sylmar earthquake shifted duct joints in many San Fernando homes, and those gaps were often patched with standard duct tape that fails within a few years. We regularly find these hidden leaks during camera inspections, with conditioned air pouring into attics that already top 150°F.
- Degraded fiberglass duct lining. Original galvanized ducts in San Fernando’s post-WWII housing stock have fiberglass lining that breaks down after sixty-plus years. It sheds into the airstream, reducing air quality and often blocking airflow entirely where sections have collapsed.
- Crushed flex duct from seismic retrofits. Beams and hardware added to attics after 1971 for structural reinforcement often squeeze flex duct runs into tight corners. Kinks and tears develop slowly, cutting airflow to distant rooms and spiking energy bills.
- Mastic seal failure from thermal cycling. Even properly sealed joints can degrade when attic temperatures swing from winter lows to summer extremes above 150°F. San Fernando’s mountain-enclosed geography traps heat more severely than outlying Valley communities, accelerating this damage.
Pricing for Duct Repair & Sealing in San Fernando, CA
We don’t do bait pricing. The number we give you before work starts is the number on the invoice. For San Fernando’s market, here’s what typical duct repair and sealing work runs:
| Service | Typical Range in San Fernando |
|---|---|
| Mastic sealant application (partial system, up to 10 joints) | $280-$450 |
| Full duct system resealing with mastic | $650-$1,100 |
| Metal duct repair (section replacement, 1-2 runs) | $340-$620 |
| Flex duct replacement (per run) | $180-$320 |
| Duct insulation (per linear foot, R-6 or R-8) | $8-$14 |
| Camera inspection and airflow test | $89-$150 (often waived with repair) |
Factors that move the price: accessibility of your attic, extent of earthquake damage, whether original ductwork can be salvaged or needs partial replacement, and insulation condition. We apply our $50 Off Any Repair Over $250 to qualifying jobs, and we offer a Free Second Opinion on Any Written Estimate if you’ve already been quoted by another company. Senior and veteran discounts of 5% apply permanently. Call (844) 685-6342 for a free, no-pressure estimate. We’ll camera-inspect your system and show you exactly what needs doing.
We Also Serve Cities Near San Fernando
Our repair crews work throughout the northern San Fernando Valley. If you’re in North Hills, Shadow Hills, Northridge, or Van Nuys, the same technicians, same equipment, and same upfront pricing apply. We schedule Duct Repair & Sealing in San Fernando and surrounding areas with route efficiency in mind, so your appointment time is reliable. We’ll be there when we say.
Serving San Fernando, CA - Our Local Coverage Area
We’re based in the San Fernando 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 - Duct Repair & Sealing in San Fernando
The only reliable way is a camera inspection of your ductwork, but there are warning signs specific to San Fernando homes. If your house was built between 1945 and 1971 and you’ve never had the ducts professionally sealed, there’s a significant chance joints shifted and were patched with tape. Look for uneven heating and cooling between rooms, dust buildup around ceiling registers, or utility bills that climbed without explanation. We include camera footage with every estimate so you can see the condition yourself. Call (844) 685-6342 to schedule - estimates are free.
Standard cloth-backed duct tape adhesive degrades rapidly above 140°F, and San Fernando attics regularly exceed that from June through September. The adhesive dries out, the tape peels, and the joint opens again. Tape was never designed as a permanent duct sealant, though it’s been misused that way for decades. Mastic compound, properly applied, remains flexible and bonded through thousands of thermal cycles. That’s why we use it exclusively and guarantee the seal for 90 days with our Done Right Promise.
Many can be repaired, but it depends on corrosion level and lining condition. If the galvanized shell is intact and the damage is limited to degraded fiberglass lining, we can clean and reline the interior or replace damaged sections. Where corrosion has perforated the metal or multiple sections have collapsed lining, partial replacement with modern duct board is more cost-effective long-term. We show you the camera footage and price both paths before you decide. Our $50 Off Any Repair Over $250 applies to either approach.
Heavy diesel particulate from the Golden State Freeway corridor settles in San Fernando at higher concentrations than in outlying Valley areas. When your duct system has leaks, your HVAC unit pulls attic air - including that particulate - into the return side and distributes it through your home. Sealed ducts with proper filtration reduce this infiltration significantly. For homes near the freeway, we also recommend checking your filter schedule more frequently and considering upgraded filtration during repair work.
If your ducts run through an unconditioned attic, yes. San Fernando’s summer attic temperatures past 150°F mean uninsulated ducts lose substantial cooling before the air ever reaches your rooms. In winter, cold attic surfaces can cause condensation on duct exteriors, promoting mold and corrosion. R-6 or R-8 insulation with sealed vapor barriers pays for itself in reduced HVAC runtime and protects the ductwork you’ve just paid to repair. We include insulation assessment in every repair estimate.
Written by Ray Castillo, Owner at Bellows Air Duct & Vent Co., serving San Fernando since 1984.