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 Alexandria
Duct repair and sealing in Alexandria typically costs $280-$720 for most residential jobs, with full-system sealing running $450-$950 depending on accessibility and the age of the ductwork. We’re CleanRun Duct Repair & Cleaning, and our crews work in Alexandria every week - from the narrow plaster-wall chases of Old Town row houses to the crawlspaces beneath Del Ray bungalows and the utility closets of West End garden apartments. Call (571) 520-6317 for a written estimate before any work starts.
Alexandria’s housing stock is older and more varied than almost anywhere else in Northern Virginia. That matters for ductwork. Brick row houses built before the Civil War got forced-air systems shoehorned into envelopes designed for coal heat or radiators. The result is cramped, non-standard duct runs that accumulate debris faster and fail in ways you won’t find in a 2005 subdivision. Our Duct Repair & Sealing team knows what to look for because we’ve scoped and repaired it - documented with photos, priced in writing, and backed by our 365-Day Done Right Promise.
Why CleanRun Air Duct Cleaning Herndon Is Alexandria’s Preferred Duct Repair & Sealing Company
We’ve served more than 52,000 homes since 2013, and a significant share of them sit inside Alexandria city limits. Our scheduling and dispatch are coordinated from our Washington, DC office, so crews reach Alexandria properties without the logistical delays that plague operators based farther west in Loudoun or Prince William counties.
Our reputation here is built on documentation, not slogans. Every job receives a Documented Photo Record - inside every duct run, before and after - delivered to the customer as part of the standard job record. Alexandria homeowners research before they buy. They want to see what was actually found, not hear that it was “really dirty.” The photo record shows a 3-inch debris build-up at the first elbow, or a flex run stapled into a wall cavity and completely detached from the trunk line.
Haven Standard Clause 1 governs every interaction: written price before any work starts, no exceptions. No “call for a quote.” No per-vent bait-and-switch. One flat price per system, agreed before a panel comes off. Our Free Second Opinion policy means you can bring us any competitor’s written estimate and we’ll put our number beside it - also in writing, also at no cost.
Technicians are background-checked, uniformed, and identified by name before arrival under Haven Standard Clause 3: Verified Crews. License details are published on this page, not buried in a footer.
Our Duct Repair & Sealing Services in Alexandria
Duct Sealing
Most Alexandria homes we inspect leak 20-30% of conditioned air before it reaches the registers. In Old Town row houses, original 1950s sheet metal joints in basements were often patched with tape and never sealed with mastic. That tape dries and fails. We remove the old material, clean the joint surfaces, and apply mastic sealant with Guardsman mesh reinforcement for a permanent seal. The result is measured: lower static pressure, more air at the register, and less humid outside air pulled into the system through the building envelope.
A typical duct sealing job in Alexandria runs $280-$550 for partial-system work and $450-$950 for full-system sealing.
Flex Duct Repair
Flex duct crushed or disconnected where it was stapled into narrow plaster-wall chases during a 1980s retrofit - this is one of the most common failures we find in Alexandria. Hidden until camera inspection reveals the break. The flex gets compressed, kinked, or pulled entirely free of the collar. We replace damaged sections with properly sized flex, support it to prevent sagging, and seal connections with mastic, not tape. In tight chases, we sometimes need to open a small access panel in the plaster - always discussed and priced in writing first.
Flex duct repair in Alexandria typically runs $180-$420 per run, depending on length and access difficulty.
Metal Duct Repair
Original 1950s galvanized sheet metal in Alexandria basements corrodes at the seams, separates at joints, and gets “repaired” by previous owners with foil tape that traps moisture. We cut out damaged sections, fabricate replacement pieces to fit non-standard dimensions, and seal with mastic and mesh. In historic structures, we preserve what we can and replace what we must - always documenting the condition with photos before touching anything.
Metal duct repair in Alexandria ranges from $220 for a single joint repair to $680 for multiple sections in a basement trunk line.
Duct Insulation & Mastic Sealant Application
Alexandria’s location in the Potomac River basin means measurably higher ambient humidity than inland Northern Virginia suburbs. Condensation forms inside ducts during shoulder-season cycling, promoting microbial growth on duct liner surfaces. Proper sealing prevents this by stopping the infiltration of humid outside air. Where insulation has degraded - common in crawlspaces beneath Del Ray bungalows - we replace it with new wrap and seal all penetrations. Mastic sealant is our standard; it remains flexible, won’t dry and crack like tape, and is the only material we use on metal-to-metal and metal-to-flex connections.
Insulation replacement with full sealing runs $380-$720 in Alexandria.
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 Alexandria
Our equipment roster includes Rotobrush agitation systems, Nikro negative-pressure extractors, and Abatement Technologies HEPA filtration - brands customers can look up independently. For sealing work, we specify Guardsman mesh and professional-grade mastic compounds. We don’t invent performance claims beyond manufacturer specifications. What we do guarantee is that the equipment is operated by trained technicians under the H.A.V.E.N. Standard, and that every job is photographed, priced in writing, and warrantied for 365 days.
Common Duct Repair & Sealing Problems We See in Alexandria Homes
- Disconnected flex runs hidden behind plaster. In Old Town row houses off King Street and Prince Street, 1980s flex duct was often stapled into wall cavities with no support. Gravity and vibration pull it free from the trunk. The register blows nothing, or blows attic air. Camera inspection finds the break. Reconnection requires access - sometimes a small plaster opening, always scoped first.
- Original 1950s sheet metal joints patched with failing tape. Basements in Del Ray and the West End still run galvanized trunk lines from the original forced-air retrofit. The tape at every joint has dried, curled, and leaked for decades. Conditioned air escapes into the crawlspace. The system runs longer. Energy bills climb. Mastic sealing fixes it permanently.
- Humid Potomac-basin air drawn through envelope leaks. Alexandria’s low elevation and river proximity create higher ambient moisture than Fairfax or Herndon. Every unsealed duct joint becomes a pathway for that humid air to enter the system, condense on cooler surfaces, and support microbial growth. Sealing is air-quality work here, not just efficiency work.
- Supply and return runs sized for a different era. Top floors in Old Town row houses often never got adequate airflow because the original retrofit couldn’t fit proper ductwork into the available chases. Homeowners add a mini-split instead of repairing the duct system. We scope and report honestly: sometimes sealing helps, sometimes the duct geometry is the limiting factor and we say so.
Pricing for Duct Repair & Sealing in Alexandria, VA
We publish ranges because Haven Standard Clause 1 requires a written price before work starts - and that price should never be a surprise.
| Service | Typical Range in Alexandria |
|---|---|
| Single flex duct repair/replacement | $180 - $420 |
| Metal duct joint repair (1-2 joints) | $220 - $380 |
| Partial-system duct sealing | $280 - $550 |
| Full-system duct sealing with mastic | $450 - $950 |
| Insulation replacement with sealing | $380 - $720 |
| Camera inspection and scope (standalone) | $150 - $220 |
What moves a job toward the higher end: multiple access points in plaster walls, non-standard duct dimensions requiring custom fabrication, working in unfinished crawlspaces with limited headroom, or systems with three or four generations of patchwork requiring scoping and prioritization. What we don’t do: quote a low per-vent figure that balloons once the truck is in your driveway. The price we write is the price you pay. Call (571) 520-6317 for a free estimate.
We Also Serve Cities Near Alexandria
Our crews work throughout the inner Northern Virginia corridor. We regularly handle Duct Repair & Sealing in Alexandria and the surrounding communities: Arlington to the north, Springfield to the southwest, Falls Church to the west, and Fairfax slightly beyond. Scheduling is coordinated from our Washington, DC office for efficient routing to all five jurisdictions.
Serving Alexandria, VA - Our Local Coverage Area
We’re based in the Alexandria 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 Alexandria
Disconnected or crushed duct runs will not move debris to the vacuum collection point, and pressurizing a broken system can blow contaminants into wall cavities. In Old Town specifically, we often find flex runs stapled into plaster chases that have pulled free - cleaning without repairing first wastes your money and can make air quality worse. We scope with a camera, report what we find, and price repairs in writing before any cleaning begins. Call (571) 520-6317 to schedule a scope.
Del Ray bungalows from the 1920s-1940s typically have crawlspace-accessible metal trunk lines with later flex additions; we work from below, seal joints with mastic, and replace degraded insulation. West End garden apartments from the 1960s-1970s have utility closets with stacked systems and longer horizontal flex runs between units; sealing here means accessing shared chases and coordinating with building management. The techniques differ. The documentation standard does not. Call (571) 520-6317 - we scope both property types regularly.
Camera inspection through the register opening, combined with airflow measurement at each vent. If a second-floor register shows negligible airflow and the camera hits a dead end or debris field where the duct should continue, we know there’s a disconnection. In one Old Town row house off King Street, our crew found a second-floor flex run stapled into a wall cavity and disconnected from the trunk, while the basement still ran original 1950s sheet metal. We used camera inspection and agitation tools under negative pressure, reconnected the flex with mastic sealant, and sealed the metal joints with Guardsman mesh and mastic. The top-floor registers finally got airflow, and the system stopped pulling humid Potomac-basin air through the wall cavity.
Alexandria’s low elevation in the Potomac River basin produces measurably higher humidity than Herndon or Fairfax. Every unsealed joint draws that moist outside air into the duct system. During shoulder seasons, when systems cycle between heating and cooling, condensation forms on duct liner surfaces. Microbial colonization follows. Sealed ducts don’t eliminate humidity, but they stop the constant infiltration that makes Alexandria’s indoor air quality problem worse than inland. Call (571) 520-6317 for a humidity and leakage assessment.
Yes. All repair and sealing work follows NADCA assessment and cleaning standards, with Abatement Technologies HEPA filtration running during any disturbance that could release particulate. In older homes with degraded duct liner or plaster dust, this matters more, not less. The HEPA unit runs continuously, and we photograph the filter condition before and after as part of the Documented Photo Record. Haven Standard Clause 2: Containment Protocol. Call (571) 520-6317 to confirm procedures for your property.
Written by Tomas Reyes, Owner at CleanRun Duct Repair & Cleaning, serving Alexandria since 2013.