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 Repair & Sealing Across Castle Hills
Duct repair and sealing in Castle Hills typically runs $280-$650 for most homes, with full flex-branch replacement on aging systems reaching $890-$1,400. We’re usually scheduling within 48 hours for Castle Hills calls. Call (830) 549-6847 for a written estimate before any work starts.
Castle Hills sits as a small incorporated enclave surrounded by San Antonio, and our crews know the area’s housing stock intimately. Dispatch and scheduling are coordinated from our Dallas-Fort Worth office, but the technicians who arrive at your Castle Hills door are working your neighborhood that week, not driving in from another metro. That matters because Castle Hills homes present a specific duct problem you won’t find in newer developments: two generations of duct material, both aging, sharing one attic space. Our Duct Repair & Sealing team has handled this exact configuration hundreds of times since we started documenting every job with before-and-after photos in 2013.
Why CleanRun Air Duct Cleaning New Braunfels Is Castle Hills’s Preferred Duct Repair & Sealing Company
Castle Hills homeowners research before they call. We built our company for exactly that customer. Every job starts with a written price delivered before a single panel comes off - Haven Standard Clause 1 - and ends with a Documented Photo Record of every duct run, included as standard. No exceptions in 52,000+ homes served since 2013.
Our reputation in Castle Hills comes from showing, not telling. Customers receive dated photos of their own duct interiors: the cedar-pollen crust on the return plenum, the separated flex collar dumping air into a 140-degree attic, the delaminated fiberglass liner shedding fibers into the airstream. These are concrete deliverables, not vague reassurances. The 365-Day Done Right Promise backs every job in writing - if it’s not right, we make it right.
Technicians are background-checked, uniformed, and identified by name before arrival under Haven Standard Clause 3: Verified Crews. All calls are answered by a live person, 24/7. And if you have a competitor’s written estimate, we provide a Free Second Opinion at no cost - our number next to theirs, both in writing.
Our Duct Repair & Sealing Services in Castle Hills
Duct Sealing with Mastic Sealant
Castle Hills’s original 1950s-60s sheet-metal trunk lines weren’t designed for the 8-to-9-month cooling seasons San Antonio now runs. Decades of heat cycling crack hard duct sealants and cause flex collars to separate from metal trunks. We apply professional-grade mastic sealant - a thick, fiber-reinforced compound that remains flexible - to every joint, seam, and penetration on rigid metal ductwork. On a typical Castle Hills ranch near Lockhill Road or West Avenue, we’ll seal 15-25 linear feet of trunk line and re-secure 4-8 flex branch connections. Mastic outlasts foil tape by years in attic heat. We photograph every sealed joint before the mastic skins over.
Flex Duct Repair
The flex branches feeding individual rooms in most Castle Hills homes were retrofit additions, often installed in the 1980s when central AC became standard. These run through attics that hit 140°F in July and August. The plastic liner becomes brittle. The wire helix corrodes. Collars pull loose from the sheet-metal trunk. We replace crushed, torn, or separated flex runs with new insulated flex duct sized to the original Manual D calculation - not whatever’s on the truck. Every replacement is photographed before insulation goes back over it. On Castle Hills jobs, flex repair is rarely a single run; it’s usually 2-4 branches showing simultaneous failure from the same heat-cycling history.
Metal Duct Repair
Original rigid sheet-metal trunks in Castle Hills homes carry a problem invisible from the outside: internal fiberglass duct liner that degrades after 50+ years of airflow and moisture. Delaminated liner sheds glass fibers into the airstream. No amount of external mastic fixes internal liner failure. We camera-inspect every metal trunk before quoting - the photo record shows you exactly what we found. Where liner is intact, we seal and preserve. Where it’s delaminating, we quote replacement or apply a specialized encapsulation coating, depending on accessibility and extent. This is the difference between a $340 sealing job and a $1,200 trunk replacement, and we document which path your system needs before you commit.
Air Leak Repair
Conditioned air leaking into a Castle Hills attic is money evaporating at 140°F. We pressurize the duct system and use calibrated smoke pencils and thermal imaging to locate leaks the eye misses - gaps around register boots, penetrations through top plates, seams where additions tied into original trunks. Every leak is sealed, photographed, and retested. A typical Castle Hills home loses 20-30% of conditioned air to attic leaks before we start; we measure the reduction with a second pressure test and include both readings in your job record.
Duct Insulation
Where original insulation has compressed, torn, or been disturbed by prior service work, we install new fiberglass duct wrap or replace insulated flex runs with properly R-rated product. In Castle Hills attics, this matters for both efficiency and condensation control - cool supply air in a superheated attic creates moisture problems that accelerate metal corrosion and flex deterioration.
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.
BeforeAfterTrusted Brands We Service in Castle Hills
Our equipment roster includes Honeywell, Aprilaire, and Abatement Technologies - brands customers can look up independently before agreeing to a price. We stock common flex diameters, mastic compounds, and collar hardware for Castle Hills’s predominant duct configurations, which means most repairs don’t wait on parts. When we encounter a specialized component - an Aprilaire zoning damper, a Honeywell media air cleaner housing - we source factory-authorized replacement rather than adapting generic parts. The brands named on your written estimate are the brands that arrive on the truck.
Common Duct Repair & Sealing Problems We See in Castle Hills Homes
- Original sheet-metal trunks with failing internal fiberglass liner. The liner installed in 1950s-60s Castle Hills construction was not formulated for 50+ years of San Antonio’s extended cooling season. It delaminates, sheds fibers, and creates a surface no sealant can bond to. We camera-inspect before quoting because external mastic on a trunk with internal liner failure is wasted money.
- Flex branch collars separated from metal trunks after decades of heat cycling. This is the classic Castle Hills leak. The attic hits 140°F, the flex collar adhesive degrades, and conditioned air dumps straight into the attic for years before anyone notices the bedroom that’s always too hot. We find these with pressure testing, re-secure with mastic and mesh, and photograph every connection.
- Cedar pollen and dust baked into return plenum surfaces. Castle Hills sits in the heart of Texas Hill Country cedar-fever territory. Ashe juniper pollen floods exterior air intakes December through February. Homeowners who changed filters infrequently in the 1970s-90s left this material to bake into duct liner, forming a yellowish-gray crust that only mechanical source removal - not a wipe-down - will clear. We run negative-pressure HEPA extraction before any sealing work begins.
- Retrofit flex branches crushed by subsequent attic work. Cable runs, Christmas decoration storage, or later HVAC additions have compressed flex ducts in many Castle Hills attics. Crushed flex creates restriction, noise, and uneven temperatures. We replace with properly supported new flex, sized to the original airflow calculation.
Pricing for Duct Repair & Sealing in Castle Hills, TX
Most Castle Hills duct sealing jobs fall between $280 and $650. Here’s how typical work breaks down:
- Mastic sealing of sheet-metal trunk lines and register boots: $280-$420
- Flex branch replacement (per run, including collar and support): $180-$290
- Full return/supply plenum repair or replacement: $340-$580
- Metal trunk liner encapsulation or partial replacement: $560-$890
- Complete system sealing with pressure-test verification: $650-$1,100
- Extensive flex-branch replacement on full 1950s-70s systems: $890-$1,400
What moves a Castle Hills job toward the higher end: multiple flex branches requiring replacement, delaminated trunk liner needing encapsulation, or additions that tied into original ductwork with incompatible materials. What keeps it lower: intact metal trunks with sound liner, accessible attics, and straightforward collar re-securing. We deliver the written price after camera inspection and pressure testing - never before. Haven Standard Clause 1. No per-vent pricing, no teaser coupons, no invoice inflation once the truck is on your drive. Call (830) 549-6847; estimates are free.
We Also Serve Cities Near Castle Hills
Our crews work Castle Hills weekly and also handle duct repair and sealing calls from New Braunfels, Cibolo, Seguin, and Schertz. The same written-price-first protocol, the same documented photo record, the same 365-Day Done Right Promise applies in every city we serve.
Serving Castle Hills, TX - Our Local Coverage Area
We’re based in the Castle Hills 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 Castle Hills
Most original metal ductwork in Castle Hills can be sealed and preserved if the internal fiberglass liner is intact. We camera-inspect every trunk before quoting. Where liner has delaminated, we quote encapsulation or partial replacement - not full system replacement unless the damage is extensive. Call (830) 549-6847 for a camera inspection and written estimate.
Your return vent pulls air from your living space through the return plenum, and in Castle Hills that plenum likely contains decades of accumulated cedar pollen and dust baked onto the surface. The yellowish-gray crust our cameras find in older Castle Hills attics is distinctive - it’s biological debris that standard household cleaning won’t touch. We remove it with negative-pressure HEPA extraction, then seal the plenum to prevent re-accumulation. Call (830) 549-6847 for an inspection.
We pressurize the entire duct system and use calibrated smoke pencils to visualize airflow escaping at joints, collars, and penetrations. Thermal imaging identifies temperature anomalies where conditioned air leaks into the attic. In tight Castle Hills attics, we also deploy a wireless camera on a flexible rod to inspect trunk lines from the register boot side. Every leak location is photographed and included in your job record.
Sealing the duct system itself won’t block pollen at the air intake, but it prevents unfiltered attic air - which carries pollen, dust, and insulation particles - from being drawn into the system through leaks. In Castle Hills homes with original ductwork, we regularly find return-side leaks that pull attic air directly into the airflow. Sealing these eliminates a major pollen pathway. For intake filtration, we inspect and can upgrade your filter housing as a separate scope. Call (830) 549-6847 to discuss both.
Yes. We run negative-pressure HEPA extraction on the supply and return ductwork before any sealing or repair work begins. This removes the debris, pollen crust, and loose fiberglass that would otherwise be disturbed during the repair process. The extraction is photographed, and the post-cleaning condition is documented before mastic application starts. It’s standard on every Castle Hills job - not an add-on.
Ready to see what’s actually inside your Castle Hills ductwork? Call (830) 549-6847 for a free estimate. We’ll deliver a written price before any work starts, document every duct run with before-and-after photos, and back the job with our 365-Day Done Right Promise.
Written by Tomas Reyes, Owner at CleanRun Duct Repair & Cleaning, serving Castle Hills since 2013.