Fast, Reliable Duct Repair & Sealing Across Kent
Most duct repair jobs in Kent run $180-$680 and are finished in a single visit, with our Duct Repair & Sealing in Kent team typically arriving same-day or next-day to homes throughout 98032, 98035, 98042, and 98064. If you’re losing heated or cooled air under your floor, smelling mustiness from the vents, or watching your energy bills climb, the problem usually traces back to ductwork that’s been sitting in a damp crawl space for thirty-plus years. Call (833) 700-5198 and we’ll send a technician who knows the East Hill subdivisions, the downtown Kent mid-century pockets, and the specific moisture problems this valley creates.
Why Bellows Air Duct & Vent Co. of Seattle Is Kent’s Preferred Duct Repair & Sealing Company
We’ve been driving to Kent since 2012, back when the East Hill build-out was still fresh and the flex duct we’re now replacing was brand new. Forty-two years of service means we’ve watched this housing stock age in real time, and we know which subdivisions near SE 256th St and 272nd St have the same original ductwork failures.
Our reviews from Kent homeowners consistently mention two things: we show up when we say we will, and the price on the phone matches the price on the invoice. No bait coupons, no upsells at the door. Our 90-Day Done Right Promise is stamped on every job, in writing. If it’s not right, we make it right with no paperwork and no arguing.
Calls are answered by a live person, 24 hours a day. Not a voicemail tree, not an app. When a Kent homeowner calls at 6 a.m. because the bedroom vents went dead overnight, someone picks up and schedules.
Our technicians are background-checked and uniformed, and they carry the same professional-grade equipment we use on jobs in Seattle: Rotobrush and Nikro cleaning systems, plus sealing and repair materials from Abatement Technologies, Honeywell, and Aprilaire. Most repairs are completed in one visit.
Our Duct Repair & Sealing Services in Kent
Flex Duct Repair
This is the work we do most often in Kent. The 1980s and 1990s ranches on East Hill were built with flexible duct routed through vented crawl spaces, and that duct has been absorbing the Green River Valley’s trapped marine moisture for decades. The inner liner degrades. The insulation wrap sags. Eventually the duct collapses under its own moisture weight and airflow to entire rooms chokes off.
We handled a job on a 1980s ranch in the East Hill subdivision near SE 256th St, where the original flex duct had collapsed from moisture weight and separated at a T-joint. We replaced the damaged section with new R-8 insulated flex duct and sealed all connections with mastic, restoring airflow to the master bedroom-a repair that arose only after our initial cleaning exposed the separation. Typical flex duct repair in Kent runs $280-$550 depending on linear footage and access difficulty.
Duct Sealing
Even duct that hasn’t collapsed is rarely airtight. In Kent’s damp crawl spaces, tape and clamp seals weaken continuously. Conditioned air leaks into the crawl space, your HVAC system runs longer, and your bills climb. Our Duct Repair & Sealing team pressure-tests the system to quantify leakage, then seals joints and connections with mastic or mechanical fasteners depending on the duct material. Most Kent homes lose 20-30% of airflow to leakage before we start. After sealing, we verify the improvement with a second pressure test. Duct sealing in Kent typically costs $350-$680 for a full system.
Mastic Sealant Application
For metal ductwork, especially in the older homes near downtown Kent around 98032, we use mastic sealant rated for antimicrobial protection. These mid-century sheet-metal trunk-and-branch systems develop condensation that supports biofilm growth, and standard tape won’t stick to contaminated surfaces. We clean the metal, apply mastic with a brush or spray depending on access, and create a flexible, permanent seal that won’t degrade in the valley’s humidity. Mastic sealing on metal duct runs $180-$340 per section.
Metal Duct Repair
Some downtown Kent homes still have original galvanized steel duct from the 1950s and 1960s. The metal itself can last, but seams rust through, hangers corrode, and connections to newer flex additions fail. We repair or replace sections, reinforce hangers, and transition properly to modern materials where needed. Metal duct repair in Kent runs $320-$620 depending on rust extent and access.
Duct Insulation
When we replace flex duct in Kent crawl spaces, we specify R-8 insulation minimum, higher than the original R-4 or R-6 that was standard in the 1980s. Better insulation means less condensation on the duct surface, which means less moisture damage and less mold risk. Duct insulation upgrades in Kent typically add $120-$240 to a repair job.
Air Leak Repair
Disconnected duct runs are common in Kent. The damp environment weakens mechanical connections, and we’ve found entire branches lying on the crawl space floor, blowing heated air directly into the dirt. We reconnect, support, and seal. Air leak repair in Kent generally runs $180-$380.
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 Kent
We stock repair materials and replacement components from Honeywell, Aprilaire, Abatement Technologies, and Guardsman, the same brands Kent HVAC contractors specify for their own jobs. Because we carry common flex duct diameters, mastic compounds, and antimicrobial sealants on our trucks, most Kent repairs don’t wait for parts. That matters on a January day when your bedroom vents are blowing cold air and the crawl space is forty degrees and wet.
Common Duct Repair & Sealing Problems We See in Kent Homes
- Flex duct collapse from moisture weight. In Kent’s damp crawl spaces, the inner liner degrades and the insulation wrap sags, causing the duct to collapse under its own moisture weight and choke airflow. We find this on nearly every East Hill job from the 1980s and 1990s build-outs.
- Joint separation at moisture-weakened connections. The continuously damp environment weakens tape and clamp seals, leading to disconnected duct runs that dump conditioned air into the crawl space. Homeowners notice cold spots, high bills, and sometimes musty smells.
- Mold and microbial growth on metal surfaces. Condensation on older sheet-metal trunks in mid-century homes near downtown Kent creates biofilm that requires special antimicrobial mastic to remediate. Standard cleaning won’t remove it, and standard tape won’t seal over it.
- Sagging unsupported flex duct. Original installers in the East Hill tract homes often used too few hangers, and decades of moisture absorption have made the duct heavier. It pools on the vapor barrier or the dirt, creating low spots where water collects and airflow stalls.
Pricing for Duct Repair & Sealing in Kent, WA
| Service | Typical Range in Kent |
|---|---|
| Flex duct repair (section replacement) | $280-$550 |
| Duct sealing (full system) | $350-$680 |
| Mastic sealant on metal duct | $180-$340 per section |
| Metal duct repair | $320-$620 |
| Duct insulation upgrade | $120-$240 add-on |
| Air leak repair (disconnected runs) | $180-$380 |
What moves a job toward the higher end: crawl spaces under 18 inches, requiring us to work on our backs; multiple disconnected runs; mold remediation that requires antimicrobial treatment before sealing; and homes where the original duct was buried under later insulation or vapor barrier work. We disclose the full price before we lift a single tool. No surprises on the bill.
Standing offers for Kent homeowners: $50 off any repair over $250, free second opinion on any written estimate from another company, and a permanent 5% senior and veteran discount. Call (833) 700-5198 for an exact quote - estimates are free.
We Also Serve Cities Near Kent
Our service area extends to East Hill-Meridian, Covington, Des Moines, and Lea Hill. The same valley moisture problems affect homes in these communities, though Kent’s East Hill concentration of 1980s-1990s flex duct makes it the most frequent call we get for moisture-related collapse and separation. If you’re in a nearby city and your home was built in the same era with the same materials, the same repair approach applies.
Serving Kent, WA - Our Local Coverage Area
We’re based in the Kent 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 Kent
Probably. Intact flex duct in Kent’s damp crawl spaces is rarely performing well. The insulation has compressed, the inner liner has micro-cracks, and connections have loosened. We camera-inspect before recommending anything, but most 1990s East Hill systems we see have significant leakage or sagging even when no section has fully collapsed. Call (833) 700-5198 and we’ll show you what the camera sees - estimates are free.
Cleaning removes debris; sealing stops leakage. They’re different jobs, and in Kent’s climate, both matter. Cleaning won’t fix the joint separations and tape failures caused by continuous moisture exposure. If your energy bills are still high or some rooms stay cold after cleaning, the duct is leaking, not dirty. We pressure-test to prove it, then seal what we find. Call (833) 700-5198 for a sealing estimate.
If water reached the duct, yes. Flex duct insulation acts like a sponge, and once saturated, it won’t dry properly in Kent’s humid under-floor environment. Mold follows quickly. We replace water-damaged sections with new R-8 insulated flex and seal all connections with mastic. Partial replacement in flood-affected zones typically runs $280-$450. Call (833) 700-5198 to schedule an inspection.
We use fiber-reinforced water-based mastic with antimicrobial additives, applied after surface cleaning. Downtown Kent’s mid-century metal trunks often carry biofilm from decades of condensation, and tape won’t adhere or last. Mastic remains flexible, seals gaps up to 1/4 inch, and inhibits regrowth. Application runs $180-$340 per section depending on access. Call (833) 700-5198 for an exact quote.
We work low, on backboards or crawl boards, with headlamps and compact tools. For spaces under 18 inches, we sometimes remove a section of vapor barrier to create a work path, then restore it. Our technicians are trained for confined-space work, and we never compress or damage existing insulation to reach the duct. Most East Hill access jobs are completed in 2-3 hours. Call (833) 700-5198 to discuss your specific crawl space.
Written by Colin Merritt, Owner at Bellows Air Duct & Vent Co., serving Kent and the Green River Valley since 2012.