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 Alexandria
Duct repair and sealing in Alexandria typically costs $280-$650 for most residential jobs, with full-system sealing in historic properties running toward the higher end. We dispatch crews daily from our Washington, DC office to Alexandria homes, and most appointments are scheduled within a week. Call (240) 318-7712 for a written estimate before any work starts.
We’ve been working in Alexandria since 2013, and the ductwork we encounter here is unlike what we see in newer Northern Virginia suburbs. Our Duct Repair & Sealing team knows the difference between a Del Ray Cape Cod with original 1950s sheet-metal runs and a Federal-era rowhouse on Prince Street where HVAC was shoehorned into walls built before mechanical systems existed. That local knowledge changes what we find, how we access it, and what fix is actually possible.
Why CleanRun Air Duct Cleaning Alexandria Is Alexandria’s Preferred Duct Repair & Sealing Company
CleanRun has served more than 52,000 homes since 2013, and a significant share of those have been right here in Alexandria, including many seeking Alexandria Dryer Vent Cleaning. Our reputation in this city was built on documentation, not promises. Every job concludes with a photo record of every duct run, before and after, delivered to the customer as a standard deliverable. Homeowners in Old Town, Del Ray, and the West End can see exactly what was found and what was changed.
Our crews are background-checked, uniformed, and identified by name before arrival - Haven Standard Clause 3: Verified Crews. Scheduling is coordinated from our Washington, DC office, with crews serving Alexandria locally. The 365-Day Done Right Promise backs every job in writing: if the work is not right, we make it right. No manager approval required. We also offer a Free Second Opinion on any written estimate from a competitor; bring us the quote and we’ll put our number next to it, in writing, at no cost.
Our Duct Repair & Sealing Services in Alexandria
Duct Sealing with Mastic Sealant
Mastic sealant is the standard for permanent, code-compliant duct sealing, and it’s often the only fix available in Alexandria’s historic district. In Old Town rowhouses where the Board of Architectural Review restricts exterior alterations, we cannot always reroute or replace deteriorated runs. Mastic sealing - a thick, fiber-reinforced compound brushed onto joints and seams - closes leaks from the inside or at accessible points without structural changes. A typical mastic sealing job in Alexandria runs $320-$580 for a standard residential system, depending on how many joints need treatment and how accessible they are in original plaster cavities.
Flex Duct Repair
Flex duct, the ribbed plastic tubing common in retrofitted systems, fails predictably in Alexandria’s older housing stock. It crushes at bends where original chases were never sized for ductwork, disconnects at collars after decades of vibration, and sags in humid attic cavities. We were called to a Federal-era brick rowhouse on Prince Street in Old Town where the upstairs registers barely moved air; a camera inspection showed a crushed 5-inch flex run in the original plaster-and-lathe wall cavity that had been jury-rigged in decades after the house was built. We reconnected and mastic-sealed the run, wrapped it with duct insulation, and the second-floor supply finally held pressure - the homeowner told us it was the first time that bedroom had heated evenly since they bought the house. Flex duct repair in Alexandria typically runs $180-$340 per run, with full replacement of multiple runs in the $450-$720 range.
Metal Duct Repair
Sheet-metal ductwork from the 1950s-1970s still supplies many Del Ray, Arlandria, and West End homes. These systems were never sealed at installation - joints were simply screwed together - and decades of thermal cycling have opened gaps that pull humid Potomac-side air into the supply side every summer. We seal accessible metal joints with mastic and replace corroded sections with matching gauge metal. Metal repair in Alexandria averages $260-$520, with costs driven by how much of the system is accessible without disturbing finished surfaces.
Duct Insulation and Air Leak Repair
Air leak repair in Alexandria often means addressing the gaps where conditioned air escapes into wall cavities, attics, or crawl spaces. In mid-century homes with shallow attic cavities, we regularly find supply leaks that have been heating or cooling the wrong space for decades. Duct insulation - typically fiberglass wrap or closed-cell sleeve - prevents condensation on cold supply lines during humid summer months. Combined leak sealing and insulation in Alexandria runs $380-$650 for most systems.
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 Alexandria
Our equipment roster includes professional-grade tools from Abatement Technologies, Guardsman, and Rotobrush - brands customers can look up independently. We stock common fittings, collars, and sealants for Alexandria jobs to avoid delays. When a historic-district repair requires specialized materials that must match existing fabric, we source through trade suppliers with next-day delivery to our Washington, DC office. Technicians carry Aprilaire and Honeywell components for compatible air-quality upgrades when access work is already underway.
Common Duct Repair & Sealing Problems We See in Alexandria Homes
- Crushed flex runs in Old Town plaster cavities. Retrofitted flex and fiberglass-lined runs in pre-Civil War rowhouses disconnect or crush at bends where the original chase was never sized for ductwork, silently starving upper-floor registers. Camera inspection is usually the only way to locate the obstruction without opening finished walls.
- Unsealed metal joints pulling humid outside air. Mid-century sheet-metal ductwork in Del Ray, Arlandria, and the West End has never been sealed, so joints pull humid Potomac-side air into the supply side every summer, feeding mold on the lining. The RH spikes regularly above 75-80% in this waterfront zone, worse than inland Fairfax County.
- Historic-district restrictions blocking replacement. The Board of Architectural Review blocks rerouting or replacing badly deteriorated runs in Old Town’s protected structures, so sealing and source removal become the only code-legal fixes instead of replacement. This is not a preference - it’s a regulatory constraint that shapes every repair decision in the district.
- Condensation and mold in shallow attic cavities. Alexandria’s position directly along the Potomac and tidal Hunting Creek keeps ground-level humidity elevated even by DC metro standards. Repeated summer humidity spikes followed by forced-air heating in winter create ideal cycling conditions for mold colonization inside duct lining, especially in older flex duct and fiberglass-lined systems.
Pricing for Duct Repair & Sealing in Alexandria, VA
We publish ranges because Haven Standard Clause 1 requires a written price before any work starts, every time. Here is what duct repair and sealing costs in Alexandria’s market:
| Service | Typical Range in Alexandria |
|---|---|
| Mastic sealant application (standard system) | $320-$580 |
| Flex duct repair (per run) | $180-$340 |
| Flex duct replacement (multiple runs) | $450-$720 |
| Metal duct repair and resealing | $260-$520 |
| Air leak repair with insulation | $380-$650 |
| Full system assessment with photo documentation | Included with any repair |
Historic-district jobs in Old Town often run toward the higher end of these ranges due to limited access and the extra time required to work within protected structures. Jobs in Del Ray and the West End with accessible basements or crawl spaces tend toward the lower end. Every estimate is free, written, and delivered before any work begins. Call (240) 318-7712 to schedule.
We Also Serve Cities Near Alexandria
Our crews work throughout Northern Virginia, including Arlington, Springfield, Falls Church, and Vienna. Each city has distinct housing stock and ductwork challenges, and our Alexandria team applies the same documentation standards and written pricing wherever we go. Scheduling is coordinated from our Washington, DC office with local dispatch to each community.
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
In Old Town’s historic district, the Board of Architectural Review often makes it illegal or structurally infeasible to reroute or replace deteriorated duct runs, so sealing is frequently the only permitted fix. New Fairfax construction has accessible, code-compliant ductwork that can simply be replaced when it fails. Sealing in Alexandria’s rowhouses is not a maintenance preference - it is often the only path to better air quality within regulatory constraints. Call (240) 318-7712 for a written assessment of what’s possible in your specific property.
We use a combination of pressure testing and camera inspection. A duct blaster or calibrated fan measures total system leakage, then we isolate sections to pinpoint where pressure drops. For buried runs, we feed a camera through accessible registers or at the plenum - the main distribution box - to visually locate crushed flex, disconnected collars, or gaps at joints. The photo record is included with every visit. Call (240) 318-7712 to schedule a documented inspection.
It is a measurable condition, not a sales line. Alexandria’s position directly along the Potomac and tidal Hunting Creek keeps ambient relative humidity regularly above 75-80% RH in summer, higher than inland Fairfax or Loudoun County. When unsealed duct joints pull this humid air into cool supply lines, condensation forms on fiberglass duct lining. Repeated seasonal cycling between humid summers and dry heated winters creates conditions where mold colonizes. We photograph this when we find it, and the images are part of your delivered job record. Call (240) 318-7712 if you want to see what your camera inspection reveals.
Yes, and it is often the most cost-effective improvement for these systems. Original sheet-metal ductwork in Del Ray was installed with unsealed screw joints and no mastic. We access the plenum and trunk lines - usually in the basement or crawl space - brush mastic onto every joint and seam, and replace any corroded sections with matching metal. The system stays original in character but performs at modern efficiency standards. Typical cost is $260-$520. Call (240) 318-7712 for a written estimate.
Uneven heating or cooling between rooms is the most reliable indicator. If one bedroom on Prince Street stays cold while the living room overheats, or if a Del Ray second floor never reaches thermostat setpoint, the issue is usually airflow restriction from a crushed or disconnected run, not just debris buildup. Cleaning improves air quality; repair restores pressure and distribution. We determine which is needed through pressure testing and camera inspection, documented in the photo record. Call (240) 318-7712 and we’ll put the diagnosis in writing before any work starts.
Ready to see what’s actually happening inside your ductwork? Call (240) 318-7712 for a free, written estimate. Every CleanRun job in Alexandria includes a Documented Photo Record of every duct run, a written price agreed before work begins, and the 365-Day Done Right Promise backed in writing. Tomas Reyes and our team will answer your call directly and schedule a time that works.
Written by Tomas Reyes, Owner at CleanRun Duct Repair & Cleaning, serving Alexandria since 2013.