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.
Before
After
Before
After
Before
AfterFast, Reliable Duct Sealing Across Middleburg
We dispatch crews to Middleburg from our Miami scheduling office, and we know the drive down I-295 and across the Shands Bridge well enough to give you a real arrival window, not a four-hour guess. If you’re off County Road 218, near Black Creek, or in one of the newer subdivisions off Blanding Boulevard, we’ve sealed ductwork in your neighborhood and we’ve seen what Clay County humidity does to it. Call us at (361) 326-5060 for a free estimate.
Why Hollis Air Duct Cleaning Is Middleburg’s Preferred Duct Sealing Company
We’ve been doing this since 2004, and our Duct Sealing team has worked enough Middleburg jobs to know the difference between a site-built ranch on Henley Road and a manufactured home off Tinker Road before we pull into the driveway. Our technicians are background-checked, uniformed, and expected to arrive inside the quoted window, price the job in writing before touching anything, and leave the site clean. That’s The Garrison Code, and it applies whether we’re sealing hard pipe in a 2010s subdivision or crawling under a mobile home near the St. Johns River.
Our 365-Day Done Right Promise covers every sealing job in writing. If the seal fails within a year, we come back and make it right at no charge, including a free second visit. No negotiation, no runaround. Phones are answered by a live person 24 hours a day, 7 days a week. You’ll talk to a human, not a callback queue.
Air Duct Sealing in Middleburg
Air Duct Sealing in Middleburg is the process of closing gaps, joints, and penetrations in your HVAC duct system so conditioned air reaches your rooms instead of leaking into your attic, crawlspace, or the damp underbelly cavity beneath a manufactured home. In Middleburg’s humid subtropical climate, with long hot summers and year-round moisture off Black Creek and the St. Johns River, leaky ducts don’t just waste money. They pull humid, mold-prone air into the system, overwork your compressor, and circulate musty smells you can’t filter out. A typical whole-house duct sealing job in Middleburg runs $850 – $1,800 for site-built homes and $650 – $1,400 for manufactured homes, depending on access, duct material, and whether the belly board needs to be addressed.
Source Removal Before Sealing
We don’t seal over dirty joints. On older ranch houses near unpaved roads, wood-heat soot and pollen coat the inside of flex duct, so tape or mastic applied over a dirty joint lifts off within a season. We clean first with rotary brush agitation and negative-air extraction, then seal. The bond holds.
Pressure Testing After the Job
We verify our work. After sealing, we run a static pressure test to confirm the system holds. In Middleburg’s manufactured-home belt, we pay special attention to whether the belly board itself is sealed, not just the duct joints above it.
Duct Sealing Services in Middleburg
Duct Sealing Services in Middleburg cover everything from spot repairs on disconnected flex runs to complete system resealing on homes where the original mastic has dried and cracked after decades of humidity cycling. We use professional-grade sealing materials, including duct mastic rated for Florida’s wet climate and reinforced foil tape where appropriate, applied after source removal so the bond is clean and permanent. For manufactured homes, our Duct Sealing Services include belly board assessment and sealing of penetrations from the underbelly side, not just the living space, which is where generic sealing fails. A typical manufactured-home sealing with belly work in Middleburg runs $900 – $1,600. Site-built homes with hard-pipe systems in newer subdivisions typically fall in the $1,100 – $1,800 range.
Manufactured Home Belly Sealing
This is where most duct sealing in Middleburg goes wrong. The belly board traps moisture and hides rodent runs. We seal from below, closing the cavity so humid crawlspace air can’t be drawn into the duct run. It’s more work. It also lasts.
Rural Property and Outbuilding Systems
Properties on unpaved roads near Jennings State Forest or along CR 218 see heavier dust and pollen loading. We seal return ducts tight so that loading doesn’t pack your blower motor and coil, masking itself as a filter problem.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Middleburg
We carry sealing and filtration products from Aprilaire, Abatement Technologies, and Guardsman, and our equipment roster includes Rotobrush rotary brush systems for source removal before we seal. For Middleburg customers, that means we don’t wait on parts shipped from out of state. If your system needs a specific collar, boot, or mastic rated for high-humidity application, we stock it. Fast turnaround matters when your AC is running 10 months a year and every day of leakage costs you money and comfort.
Common Duct Sealing Problems We See in Middleburg Homes
- Belly board failures on manufactured homes. The underbelly cavity stays damp year-round along Black Creek. Sealing from inside the living space leaves the crawlside open, so humid air keeps entering and the seal fails within a season. We seal from below.
- Dust-packed returns on rural properties. Unpaved road dust gets pulled into leaking return ducts and packs the blower motor and coil. Homeowners replace filters monthly and still see dust. The real problem is the return leak, not the filter.
- Mastic failure on older ranch houses. Homes from the 1970s-90s near Middleburg’s older core often have original duct mastic that dried and cracked through twenty years of humidity cycling. It looks sealed. It isn’t.
- Flex duct rodent damage in wooded lots. Properties near Jennings State Forest or along CR 218 see rodent runs chew through flex duct under the belly board. The hole pulls humid, unfiltered air straight into the bedroom supply. Sealing requires replacing the damaged section, not just taping over it.
Pricing for Duct Sealing in Middleburg, FL
Here’s what duct sealing actually costs in Middleburg’s market. A manufactured home with belly board work typically runs $900 – $1,600. An older site-built ranch with flex duct in the crawlspace runs $850 – $1,500. Newer site-built homes with hard-pipe systems in subdivisions off Blanding Boulevard or Henley Road run $1,100 – $1,800. What moves the price: access (crawlspace height, belly board condition), duct material (flex vs. hard pipe), extent of damage requiring replacement versus sealing only, and whether source removal is needed before mastic will bond. We give you a written price before any work starts. One flat price per system. No per-vent add-ons, no surprises when the technician is already inside. Call (361) 326-5060 for a free estimate.
We Also Serve Cities Near Middleburg
Our crews work throughout Clay County and Northeast Florida, including Middleburg and the surrounding communities of Orange Park, Green Cove Springs, Fleming Island, and Jacksonville. Each job follows The Garrison Standard: written price, written guarantee, arrive inside the window, leave the site clean.
Serving Middleburg, FL - Our Local Coverage Area
We’re based in the Middleburg 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 Middleburg
Because the belly board under the floor traps moisture and hides rodent runs and mold that no vent-and-return cleaning reaches. In Middleburg’s low, wooded stretch along Black Creek and the St. Johns River corridor, that underbelly cavity stays damp enough year-round that sealing from inside the living space always fails. We seal the belly penetrations from below so humid crawlspace air can’t be pulled into the duct run. Call (361) 326-5060 for an exact quote on your home.
Every 3 to 5 years for properties on unpaved roads or open land, because dust and pollen loading is heavier than in paved subdivisions. We recommend a pressure test every other duct cleaning to catch return leaks before they pack your blower motor. Call (361) 326-5060 to schedule a check.
Yes, when the belly board is included. Sealing only the attic joints leaves the underbelly open, so you’re still pulling damp crawlspace air into the system. Proper belly sealing closes that pathway, reduces condensation inside the ducts, and lets your dehumidifier or AC actually control indoor moisture instead of fighting a leak. Call (361) 326-5060 for a free assessment.
We inspect the duct run, test static pressure to locate leaks, remove dust and debris with a rotary brush and negative-air machine, then seal joints with mastic or reinforced foil tape rated for the application. For outbuildings near Middleburg on rural lots, we pay special attention to return duct integrity, because shop dust and pollen load the system fast if the return is pulling unfiltered air. Written price before work starts, same as any job. Call (361) 326-5060 to book.
Sometimes, on site-built homes with hard-pipe attic systems. Never on manufactured homes where the belly board is the primary leak path. If a contractor promises to seal your Middleburg mobile home without addressing the underbelly, the seal will fail before the next humid season. We tell you upfront what access is required. Call (361) 326-5060 for an honest evaluation.
Written by Roy Castellanos, Owner at Hollis Air Duct Cleaning, serving Middleburg and Northeast Florida since 2004.