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 Repair & Sealing Across Gaithersburg
Duct repair and sealing in Gaithersburg typically costs $340-$890 for most residential jobs, with flex duct replacement running higher when multiple runs in Montgomery Village-era townhomes have failed at the collars. Our crews are dispatched from the Washington, DC office and carry full inventories of flex duct, mastic, and sheet-metal fittings sized for the 1970s-1990s housing stock that dominates this market. Call (571) 526-0015 for a written estimate before any work starts.
We’ve been working inside Gaithersburg ductwork since 2013. The housing here tells a specific story: tens of thousands of townhomes and garden condos built during the Montgomery Village expansion, now 40-50 years old, with original spiral-wound flex duct that was never designed to last this long. When we open a chase in a Montgomery Village unit off Watkins Mill Road or a Kentlands townhome near Main Street, we know what we’re going to find before the camera goes in. That local pattern recognition matters. It means we quote the right scope the first time, not a low cleaning price that balloons once we’re inside.
Why CleanRun Air Duct Cleaning Fairfax Is Gaithersburg’s Preferred Duct Repair & Sealing Company
Gaithersburg homeowners have left us detailed reviews citing the photo records we deliver, the written prices they received before any panel came off, and the specific neighborhoods we named back to them during scheduling. We’ve served more than 52,000 homes since 2013, and the Gaithersburg jobs are among the most documented in our system because the failure modes here are so consistent we can show customers before-and-after sets that match their exact building type.
Our response time to Gaithersburg is same-week scheduling for standard duct repair and sealing, with dispatch coordinated from our Washington, DC office. Crews arrive with the H.A.V.E.N. Standard identification protocol: background-checked, uniformed, and named before they knock. Haven Standard Clause 3: Verified Crews applies to every appointment.
We know the difference between a Montgomery Village-era flex duct pulled apart at a sheet-metal collar and a Kentlands kink at a tight new-urbanist bend. That distinction changes the repair scope, the price, and whether cleaning alone is even possible. Customers in Gaithersburg tell us other companies quoted cleaning without inspecting; we don’t quote repair work until we’ve run the camera and shown them what it recorded.
Our Duct Repair & Sealing Services in Gaithersburg
Duct Sealing
Most Gaithersburg townhomes lose 20-30% of conditioned air through leaks at joints, collars, and chase penetrations before it ever reaches the registers. In Montgomery Village units, we regularly find supply ducts dumping air into shared-wall cavities where the flex has separated from the trunk. Our Duct Repair & Sealing crews seal accessible joints with mastic - a thick, fiber-reinforced compound that remains flexible after curing - and supplement with mechanical fasteners at high-stress collars. The work is photographed before and after, and the seal integrity is noted on the written job record.
Flex Duct Repair
Flex duct repair is the most common scope change we encounter in Gaithersburg. The original spiral-wound flexible runs in Montgomery Village townhomes were rated for roughly 25 years; they’re now 40-50 years old. We replace collapsed, separated, or rodent-damaged flex with new insulated runs, properly supported at maximum 4-foot intervals to prevent sagging, and sealed at collars with mastic and draw bands. A typical single-run replacement in a Gaithersburg townhome runs $280-$450; multiple runs in a full attic chase can reach $780-$1,200.
Metal Duct Repair
Downtown Gaithersburg’s older single-family stock and some Montgomery Village buildings with later renovations include galvanized steel trunk lines and rectangular ductwork. We repair separated seams, patch corrosion holes, and replace failed dampers. Metal duct repair in Gaithersburg typically runs $340-$620 depending on accessibility and whether the trunk is in a basement or a sealed chase.
Duct Insulation
Gaithersburg’s humid Piedmont climate means attic ductwork experiences severe thermal cycling. In summer, 140°F attic air surrounds supply ducts carrying 55°F conditioned air; in winter, the reverse. Failed insulation creates condensation that feeds mold and reduces system efficiency. We replace degraded duct insulation with new vapor-barrier-wrapped material, sealed at all seams, particularly on attic supply runs in Kentlands and Lakelands townhomes where tight chase construction makes access difficult.
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.
BeforeAfterTrusted Brands We Service in Gaithersburg
We stock parts and materials from manufacturers whose specifications are publicly available for customer verification: Rotobrush for mechanical agitation and contact cleaning, Abatement Technologies for negative-air machines and HEPA filtration, and Aprilaire for media filters and whole-home air quality components used during repair and sealing jobs. Our Gaithersburg crews carry common flex duct diameters, collar sizes, and mastic inventory on every truck, so most repairs are completed in a single visit without waiting for parts.
Common Duct Repair & Sealing Problems We See in Gaithersburg Homes
- Collar separation in Montgomery Village flex duct. The original spiral-wound flexible supply lines have pulled away from sheet-metal trunk collars where they enter attic or wall chases. Decades of vibration, debris weight, and rodent activity in shared-wall construction cause this failure mode. The result is conditioned air dumped into unconditioned cavities and weak airflow at registers.
- Mold and biofilm in below-grade returns. Garden-style condos around Gaithersburg, including units near Montgomery Village Avenue and in Kentlands/Lakelands lower levels, have return-air runs that stay damp year-round. Piedmont humidity regularly exceeds 70-80% for weeks in summer, creating conditions inside flex duct that support mold colonization. Cleaning alone won’t solve this; the duct must be repaired or replaced and the source of moisture addressed.
- Rodent-damaged flex in shared-wall chases. Attached townhome construction in Montgomery Village creates continuous wall cavities that rodents travel. Chewed flex insulation creates pinhole leaks that leak supply air into walls while simultaneously pulling wall-cavity air into returns. This supply-and-return crossover degrades air quality and system efficiency simultaneously.
- Kinked flex at tight Kentlands/Lakelands bends. The new-urbanist design of 1990s Gaithersburg neighborhoods used compact chases and tight turns to preserve architectural detail. Flex duct at these bends collapses over time, restricting airflow and increasing static pressure on the blower motor.
Pricing for Duct Repair & Sealing in Gaithersburg, MD
We publish ranges because Haven Standard Clause 1 requires a written price before any work starts. Here’s what duct repair and sealing costs in the Gaithersburg market:
| Service | Typical Range in Gaithersburg |
|---|---|
| Mastic sealing of accessible joints (per system) | $340-$520 |
| Single flex duct run replacement | $280-$450 |
| Multiple flex run replacement (full attic chase) | $780-$1,200 |
| Metal duct seam repair / patching | $340-$620 |
| Duct insulation replacement (per run) | $180-$340 |
| Full system inspection with camera and written scope | $0 (free with repair commitment) |
Three factors move Gaithersburg jobs within these ranges: accessibility (tight Montgomery Village chases take longer), material type (flex versus metal), and whether the scope changes once the camera reveals hidden damage. We show you the camera footage before quoting. The price you approve in writing is the price on the invoice. No per-vent add-ons, no equipment fees, no post-work surprises.
We also offer a Free Second Opinion on any written estimate from another company. Bring their quote; we’ll put our number next to it in writing.
We Also Serve Cities Near Gaithersburg
Our crews work throughout Montgomery County, including Gaithersburg and neighboring Rockville and Silver Spring. Dispatch and scheduling are coordinated from our Washington, DC office. Each city gets the same H.A.V.E.N. Standard protocol: written price first, documented photo record last, 365-Day Done Right Promise on every job.
Serving Gaithersburg, MD - Our Local Coverage Area
We’re based in the Gaithersburg 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 Gaithersburg
It depends on what the camera shows, and in Montgomery Village-era townhomes we find replacement is needed more often than cleaning alone. The original spiral-wound flex has typically degraded at collar connections or collapsed from debris weight; if the duct has separated from the trunk or is crushed, cleaning will not restore airflow and may damage it further. We run a camera inspection first, show you the footage, and quote repair or replacement before any work starts. Call (571) 526-0015 to schedule.
A technician accesses the plenum (the main distribution box at your furnace or air handler), inserts a borescope camera into each duct run, and records video of the interior condition. In Gaithersburg townhomes we pay particular attention to collar connections at trunk takeoffs, signs of rodent activity in shared-wall chases, and moisture staining that indicates condensation or past leaks. You receive the photo record as part of the standard job documentation. The inspection itself is free when you commit to the recommended repair scope.
Gaithersburg sits in the humid Piedmont transition zone where summer humidity routinely exceeds 70-80% for weeks at a time. Below-grade return-air runs in garden-style condos stay cool and damp year-round, creating conditions inside flex duct that support mold and biofilm growth. The 1970s-80s construction in Montgomery Village used uninsulated or poorly insulated flex in these locations, accelerating the problem. Cleaning removes visible growth but does not fix the underlying moisture issue; we typically recommend duct replacement with properly insulated runs and, in some cases, dehumidification support.
We use mastic - a thick, fiber-reinforced sealant applied with a brush or gloved hand - for all accessible joints in Gaithersburg homes. Mastic outperforms tape over time because it remains flexible after curing and does not degrade from thermal cycling. In Montgomery Village and Kentlands townhomes where ducts have been leaking into wall cavities for decades, proper sealing routinely reduces blower run time and improves register airflow. The before-and-after static pressure readings are included in your job record.
We recommend repair when the damage is localized to one or two runs or specific collar connections, which is common in 1990s Kentlands/Lakelands construction. Full replacement makes more sense when Montgomery Village-era flex duct has reached end of life across multiple runs, or when repeated rodent damage has compromised the insulation vapor barrier. We show you the camera footage, explain which failure mode your system exhibits, and quote both options when both are viable. The decision is yours after you’ve seen the evidence. Call (571) 526-0015 for a written estimate.
We were called to a garden-style condo off Watkins Mill Road in Montgomery Village where the homeowner complained of dust streaking from the registers after every HVAC cycle. Camera inspection showed the original spiral-wound flex supply in the attic chase had partially collapsed and separated at the sheet-metal collar - debris weight and decades of age had pulled it free. We reconnected and sealed the collar, replaced the failed 15-foot flex run, then ran the full source-removal clean under negative pressure with HEPA filtration before sealing the remaining accessible joints with mastic. The photo record showed the new run, the sealed collar, and the cleaned trunk. The homeowner had that record in writing before we packed up.
That’s how we work in Gaithersburg. Written price first. Camera evidence. Documented result. Then the 365-Day Done Right Promise, backed in writing, not just stated in marketing copy.
Call (571) 526-0015 for a free estimate on duct repair and sealing in Gaithersburg. We’ll schedule the inspection, run the camera, and put a written price in your hand before any panel comes off.
Written by Tomas Reyes, Owner at CleanRun Duct Repair & Cleaning, serving Gaithersburg since 2013.