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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Before
AfterFast, Reliable Duct Repair & Sealing Across Sterling
Duct repair and sealing in Sterling, VA typically costs $340-$890 for most residential jobs, with full-system sealing running higher depending on accessibility and the condition of existing ductwork. Our crews are dispatched from our Washington, DC coordination office and carry full inventories of mastic sealant, flex duct, and metal fabrication materials so most Sterling repairs are completed in a single visit. We’ve worked in Sterling since 2013, and the housing patterns here - from 1960s Sterling Park colonials to 1990s Cascades townhomes to brand-new Dulles Corridor builds - create a wider range of duct failure modes than almost anywhere else in Loudoun County.
Call (571) 487-7204 for a written estimate before any work starts. Every quote is delivered in writing under Haven Standard Clause 1.
Why CleanRun Air Duct Cleaning Leesburg Is Sterling’s Preferred Duct Repair & Sealing Company
We’ve completed duct repair and sealing work in more than 1,200 Sterling homes since 2013, and our Duct Repair & Sealing team has built its reputation on one practice that distinguishes us in this market: we photograph the inside of every duct run before touching anything, then again when the work is done. Sterling homeowners receive that photo record as a standard deliverable, not an upsell.
Our technicians are background-checked, uniformed, and identified by name before arrival under Haven Standard Clause 3: Verified Crews. Tomas Reyes established the H.A.V.E.N. Standard in 2013 precisely because this industry runs on verbal promises and vanishes after payment. Every Sterling job carries the 365-Day Done Right Promise in writing - if the seal fails, the repair doesn’t hold, or the documented result doesn’t match what we delivered, we return and make it right.
We answer calls with live people, 24/7. Scheduling to Sterling is typically within 48-72 hours for non-urgent repairs. We don’t manufacture urgency.
Our Duct Repair & Sealing Services in Sterling
Duct Sealing
Duct sealing in Sterling addresses the conditioned air leaking into attics, crawl spaces, and wall cavities before it ever reaches your registers. In a typical two-story colonial near Cascades Parkway, we measure duct static pressure and often find 20-30% air loss at mastic joints that have dried and cracked over 25-35 years. Our sealing process uses professional-grade mastic compound applied to every accessible joint, boot connection, and plenum seam, then pressure-tested to verify the seal. For Sterling’s newer homes along the Dulles Corridor, we also seal boot-to-floor joints that builders left unsealed during construction, stopping the migration of drywall dust and attic air into living spaces.
Flex Duct Repair
Flex duct repair is the most common service call we receive from Sterling’s 1980s-1990s subdivisions. The corrugated plastic liners in these systems degrade in attic heat that regularly exceeds 130°F during Northern Virginia summers. In Sterling’s two-story colonials, we find flex duct that has sagged at low spots, creating debris traps where humidity condenses and mold establishes. Our crews replace damaged flex runs with new insulated ductwork, support it properly to eliminate sag, and seal all connections with mastic. We use Nikro negative-pressure extraction equipment during the repair to prevent debris migration into occupied spaces.
Metal Duct Repair
Metal duct repair in Sterling concentrates in the original Sterling Park subdivision, where galvanized steel trunks from 1967-1975 have reached 50+ years of service. We find separated seams, rust-through at condensation points, and early-generation fiberglass batt insulation that has compressed or crumbled, shedding fibers directly into the airstream. Our metal repairs include seam sealing with mastic, section replacement with matching gauge steel, and proper insulation with modern foil-faced materials. This is fundamentally different work than flex duct repair - it requires sheet metal fabrication skills and equipment that many duct-only cleaners don’t carry.
Duct Insulation
Duct insulation in Sterling addresses two distinct problems depending on your home’s era. In Sterling Park’s metal systems, we replace degraded fiberglass batt with modern foil-faced insulation that won’t shed fibers. In Cascades-era and newer homes with flex duct, we inspect the factory-installed insulation jacket for compression, water staining, or UV damage in attic installations, then replace or supplement as needed. Proper insulation prevents the condensation cycles that accelerate duct degradation in Sterling’s humid summers and reduces the thermal loss that forces your air handler to run longer.
Mastic Sealant Application
Mastic sealant is the backbone of durable duct sealing, and we apply it as a standalone service when tape or old sealant has failed. In Sterling, we see original mastic from the 1990s that has become brittle and cracked, particularly at plenum connections and boot joints. We remove failed material, clean the joint surface, and apply new fiber-reinforced mastic compound that remains flexible through temperature cycles. Unlike foil tape, which degrades in attic heat, properly applied mastic lasts the life of the duct system. We document every sealed joint with before-and-after photos.
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.
Before
AfterTrusted Brands We Service in Sterling
Our equipment roster includes Rotobrush agitation systems for debris removal, Nikro HEPA-filtered negative-pressure machines for containment during repair work, and Honeywell and Aprilaire air quality components for integration with your existing HVAC controls. We stock common flex duct diameters, mastic compounds, and metal fabrication materials so Sterling repairs aren’t delayed waiting for parts. If your system includes specialized components, we’ll identify the manufacturer during our initial inspection and source accordingly - but most Sterling residential repairs are completed with materials we carry on every truck.
Common Duct Repair & Sealing Problems We See in Sterling Homes
- Builder handover debris in new Dulles Corridor homes: Our crews routinely pull pounds of drywall dust, joint compound grit, and framing sawdust from supply and return ducts in Sterling subdivisions built since 2020. Builders pencil ductwork in before final cleanup, and the first cooling season pulls all of it through your air handler and into your living space. A two-year-old colonial can need source removal sooner than a fifty-year-old Sterling Park ranch.
- Flex duct collapse in unconditioned attics: Sterling’s two-story colonials with supply trunks running through attic spaces experience repeated heat cycles above 130°F. Flex duct liners soften, sag at low spots, and delaminate - creating debris traps where humidity condenses and seals fail. We find this pattern from the Cascades through newer Sterling subdivisions with similar roofline designs.
- Mastic seal failure at boot and plenum joints: Cascades-era systems installed 1985-2000 are hitting the 25-35-year threshold where original mastic has dried and cracked. Duct static pressure drops, attic air pulls into the airstream, and your air handler works harder to deliver the same volume. This is invisible from the living space but measurable with proper testing.
- Compressed or crumbling fiberglass insulation in Sterling Park metal systems: The original galvanized steel trunks in late-1960s and early-1970s homes were wrapped in early-generation fiberglass batt that has now compressed or disintegrated over five decades. Unlike flex-duct systems just a mile away in the Cascades, these metal trunks actively shed insulation fibers into the airstream - a condition requiring different remediation equipment and techniques.
Pricing for Duct Repair & Sealing in Sterling, VA
Most residential duct sealing jobs in Sterling run $340-$620 for partial-system sealing of accessible joints and boots. Full-system sealing, including attic trunk lines and all branch connections, typically ranges $680-$890 for an average 2,000-square-foot home. Flex duct repair or replacement is priced per run, with most single-run repairs between $280-$450 including materials and labor. Metal duct repair in Sterling Park’s older systems starts around $380 for seam sealing and can exceed $1,200 if multiple sections require fabrication and replacement.
| Service | Sterling Price Range |
|---|---|
| Partial duct sealing (accessible joints) | $340-$620 |
| Full-system duct sealing | $680-$890 |
| Single flex duct run repair/replacement | $280-$450 |
| Metal duct seam sealing (Sterling Park-era) | $380-$650 |
| Metal duct section replacement | $850-$1,200+ |
What moves the price: accessibility (crawl space vs. full attic), the number of runs affected, whether we can repair in place or must fabricate replacement sections, and the condition of existing insulation that may need removal before sealing. We deliver a written price before any work starts, every time, under Haven Standard Clause 1. No per-vent pricing. No coupon bait-and-switch. Bring a competitor’s written estimate and we’ll provide a Free Second Opinion at no cost.
Call (571) 487-7204 for an exact quote - estimates are free and include the documented photo record.
We Also Serve Cities Near Sterling
Our crews work throughout Loudoun and Fairfax Counties, with regular routes to Sterling, Herndon, Reston, Great Falls, and Chantilly. The same written pricing, documented photo record, and 365-Day Done Right Promise apply in every service area. Dispatch and scheduling are coordinated from our Washington, DC office; crews serve Sterling locally with materials stocked for same-visit completion of most repairs.
Serving Sterling, VA - Our Local Coverage Area
We’re based in the Sterling 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 Sterling
Because builders install ductwork before drywall, final paint, and cleanup, new homes in Sterling’s Dulles Corridor subdivisions routinely contain construction debris that the HVAC system distributes on first use. Our field crews have pulled pounds of drywall joint compound dust, framing sawdust, and paint overspray from supply trunks in two-year-old Sterling colonials. The builder should have protected and cleaned the ducts before handover; most don’t. Call (571) 487-7204 for an inspection with documented photos - estimates are free.
Yes. Sterling Park’s 1967-1975 galvanized steel trunks require mechanical brushing and contact vacuuming to remove debris adhered to metal surfaces, plus careful handling of degraded fiberglass insulation that can shed fibers if disturbed improperly. Cascades-era flex duct systems need gentler agitation to avoid damaging the plastic liner, with negative-pressure containment to prevent debris escape at torn or disconnected joints. We assess the duct material during our initial camera inspection and select the appropriate method - documented in your written scope before work begins.
Duct sealing fixes the conditioned air leaking into your attic, crawl space, or wall cavities instead of reaching your registers. In Sterling’s two-story colonials with attic trunk lines, we typically measure 20-30% air loss at cracked mastic joints and unsealed boot connections. Sealing restores duct static pressure, reduces runtime on your air handler, and stops attic air - dust, insulation particles, and summer humidity - from being pulled into your breathing air. The improvement is measurable with before-and-after pressure testing, and we photograph every sealed joint for your record.
Cleaning addresses debris inside the ducts; repair addresses physical damage to the ductwork itself. Signs you need repair include visible flex duct sagging or disconnection in attic spaces, airflow that’s weak at some registers but strong at others, musty odors that persist after cleaning, or energy bills that climbed without thermostat changes. Our camera inspection shows you the difference - collapsed flex runs, separated metal seams, or failed mastic joints are repair issues that no amount of cleaning will fix. We deliver the inspection photos with a written scope that separates cleaning from repair so you decide with full information.
Yes. Northern Virginia attic temperatures regularly exceed 130°F in summer, and in Sterling’s prevalent two-story colonials where supply trunks run through unconditioned attic spaces, that heat softens flex duct liners, accelerates mastic drying and cracking, and creates condensation cycles where humid attic air contacts cooled duct surfaces. The result is sagging flex that traps debris, failed seals that leak conditioned air, and in severe cases, mold growth at low points. We see this pattern from the Cascades through newer Sterling subdivisions with similar roofline and duct routing designs. Proper repair includes not just fixing the damage but improving support and insulation to slow recurrence.
Written by Tomas Reyes, Owner at CleanRun Duct Repair & Cleaning, serving Sterling and Loudoun County since 2013.