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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After
Before
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Before
AfterFast, Reliable Duct Sealing Across South Miami
Homes in South Miami lose 20 – 30% of conditioned air through leaky ductwork before it ever reaches the rooms. In our market, a typical duct sealing job runs $850 – $2,400 depending on access and how much of the system needs work. We dispatch crews from our Miami office and serve South Miami neighborhoods including the areas near the Metrorail station, along US-1, and throughout the residential blocks east of Red Road.
We’ve been working in South Miami long enough to know the local pattern: post-1945 concrete-block ranches with original flex duct squeezed into furred-down soffits, no access panels, and decades of humidity damage. Our Duct Sealing team doesn’t guess at what’s behind your drywall. We run a camera first, write the price down, and only then start cutting access hatches or applying mastic. Call (361) 326-5060 for a free estimate.
Why Hollis Air Duct Cleaning Is South Miami’s Preferred Duct Sealing Company
Hollis Air Duct Cleaning, founded in 2004 as part of the Garrison Partners family, operates under The Garrison Standard: written prices, written guarantees, and a 365-Day Done Right Promise on every job. In South Miami, that standard matters more than in most markets because the work is often invasive. Cutting into a soffit or wall chase means coordinating with HOAs, submitting work plans to neighboring units, and re-trimming everything to pass inspection. We’ve done it enough times to know the local building department’s expectations and the common HOA formats.
Our technicians are background-checked and uniformed. You know who’s arriving before they knock. Phones are answered by a live person 24 hours a day, 7 days a week. No voicemail loops, no callback queues.
The 365-Day Done Right Promise covers every repair for a full year. If the seal fails, if the musty odor returns, if a joint reopens, we come back at no charge. That includes a free second visit, not a negotiation. We put it in writing before any work starts.
We serve South Miami with equipment from Rotobrush, Nikro, and Abatement Technologies. These are the same negative-air machines and rotary brush systems commercial crews use, not hardware-store gear. When we seal a duct in a 1950s ranch near Sunset Drive or a 1970s condo along US-1, we do it by the book.
Air Duct Sealing in South Miami
Air Duct Sealing in South Miami is rarely a simple mastic-and-mesh job. Because the city’s post-1945 building code sealed many furred-down soffits and wall chases without factory access panels, we often start by cutting an access hatch into drywall, running a camera inspection, and re-trimming the opening before the HOA walkthrough. Add South Miami’s year-round dew points in the 70s and mature tree canopy shading every roof, and attic flex duct can breed mold on the plenum within weeks of a rainy-season outage. That’s why our jobs here typically start with a moisture check and coil sanitation before any sealing begins. A typical whole-system sealing in South Miami runs $850 – $2,400, with partial repairs on one or two accessible runs starting around $350 – $600.
Access Panel Cutting and Re-Trimming
When a soffit or wall chase was sealed without an access panel, there’s no way to reach the joint that failed. We cut a clean hatch, document the work with photos for the HOA, seal the duct with mastic and fiberglass mesh, then re-trim and paint-match the opening. The homeowner gets before-and-after photos of both the duct and the finished surface.
Moisture Assessment Before Sealing
Sealing a wet duct traps moisture inside. In South Miami’s climate, we check for condensation pooling in low spots of attic flex duct and verify the drain pan is flowing freely. If we find standing water or active mold, we dry and treat first, then seal. The seal lasts longer, and the musty odor actually clears instead of returning in six weeks.
Duct Sealing Services in South Miami
Duct Sealing Services in South Miami address the specific failure modes this climate and housing stock produce. Original galvanized supply trunks from the 1950s – 1960s corrode at the seams. Flex duct runs in tight attic spaces get crushed by storage or sag until they disconnect from their collars. And because so many joints are concealed behind sealed soffits, a homeowner can have high utility bills and uneven cooling for years without knowing where the air is going. Our service includes static-pressure testing to locate leaks, camera inspection to verify what we found, and written documentation of every sealed joint. A typical whole-home Duct Sealing Service in South Miami runs $850 – $2,400 depending on linear feet of duct and how many access openings we need to create.
Static Pressure Testing and Leak Location
We pressurize the system and measure where the pressure drops. This tells us whether the leak is on the supply side, the return side, or both. In South Miami’s older homes, we often find return-side leaks pulling hot, humid attic air directly into the system. That humid air is what keeps the musty smell circulating even after a standard cleaning.
Mastic and Mesh Sealing of Joints and Collars
We use duct sealing mastic, not tape. Mastic remains flexible, handles South Miami’s thermal expansion cycles, and won’t dry out and fall off like foil tape. We embed fiberglass mesh for structural support at joints and collars, then test again to confirm the pressure holds. The homeowner sees the numbers before and after.
What happens when you call
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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 South Miami
We stock parts and sealing materials from Abatement Technologies, Aprilaire, and Guardsman for South Miami jobs. Abatement Technologies’ negative-air machines let us contain dust and mold spores while we work in occupied homes. Aprilaire media filters and Guardsman antimicrobial treatments address the mold pressure that South Miami’s humidity creates. We don’t have to order parts and wait. Most jobs start the same visit we quote, and if your system needs a filtration upgrade after sealing, we carry the components in the van.
Common Duct Sealing Problems We See in South Miami Homes
- Condensation re-wets sealed joints after summer downpours. South Miami’s June – November rainy season dumps water on roofs that stay warm. Attic dew points spike during outages. Mastic applied over damp metal or flex duct lifts within weeks. We dry first, then seal.
- Sealed soffits hide disconnected flex runs from pressure tests. A static-pressure test can’t reach a gap inside a furred-down chase with no access panel. The system reads as “sealed” but the dining room stays hot. We cut access, camera-inspect, and fix what’s actually broken.
- Mold on the plenum defeats the seal from the inside. After hurricane-season outages, we routinely find mold blooming on the evaporator coil and plenum. Skip the antimicrobial step, and the odor returns through even a perfect seal. We coil-sanitize before we seal.
- HOA-shared chases in multifamily buildings complicate scheduling. Dense condos near downtown South Miami and along US-1 have individually metered air handlers in shared wall chases. We coordinate with building management and neighboring units, submit work plans, and schedule around association rules.
Pricing for Duct Sealing in South Miami, FL
Duct sealing in South Miami typically costs $850 – $2,400 for a whole-home system, with smaller partial repairs starting at $350 – $600. What moves the price: how many access panels we need to cut and re-trim, whether the job requires coil sanitation and antimicrobial treatment, and whether we’re working in a tight attic or a sealed soffit that demands surgical drywall work. Condos with HOA coordination add time but not hidden fees. We write the price down before any cutting or sealing begins. One flat price per system, no per-vent add-ons, no ballooning at the door. Every estimate is free. Call (361) 326-5060.
We Also Serve Cities Near South Miami
Hollis crews work throughout South Florida, including Jacksonville, Miami, Tampa, and Orlando. Each location is independently owned and operated under The Garrison Standard, with the same written pricing and 365-Day Done Right Promise. If you’re outside South Miami city limits, we can still quote and schedule from our Miami office.
Serving South Miami, FL - Our Local Coverage Area
We’re based in the South Miami 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 South Miami
Yes, most multifamily buildings in South Miami require HOA notification and sometimes a building permit for ductwork that involves cutting into shared chases or soffits. We submit work plans to the association and coordinate with neighboring units before we arrive. Call (361) 326-5060 and we’ll walk you through your building’s specific requirements.
The musty odor usually means mold is growing on the evaporator coil or plenum, or a return-side leak is pulling humid attic air into the system. Cleaning alone doesn’t fix it. We check for moisture intrusion, sanitize the coil, and seal the return leaks so the system stops circulating humid, mold-laden air. Call (361) 326-5060 for an inspection.
Yes. In a 1950s concrete-block ranch near the South Miami Metrorail station, our tech found the original galvanized supply trunk crushed under a chair brace and a flex run disconnected from its collar in the furred-down soffit above the dining room. We ran a camera inspection, sealed the joint with mastic and mesh, and after the negative pressure source removal, the return-side static pressure dropped and the musty odor finally cleared. We had to cut an access panel because the soffit was sealed with no factory access, then re-trim and re-seal it before the homeowner’s HOA walkthrough. Call (361) 326-5060 for a free estimate.
Yes, but only if the sealing includes return-side leaks. In South Miami’s humidity, return leaks pull attic air laden with dust, pollen, and mold spores directly into the system. Sealing those leaks stops the infiltration. We test static pressure on both supply and return sides to find every leak. Call (361) 326-5060 to schedule.
Power outages during June – November stop the AC while outdoor dew points stay in the 70s. Attic temperatures spike, then drop when power returns, causing condensation to pool in low spots of flex duct. Within weeks, mold blooms on the plenum and mastic lifts off damp metal. We check moisture levels and drain-pan function before sealing anything. Call (361) 326-5060 after any extended outage.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving South Miami since 2004.