Fast, Reliable Duct Repair & Sealing Across Portland
Duct repair and sealing in Portland typically runs $280–$650 for most residential jobs, with same-day or next-day scheduling available across the metro. We’re familiar with the vented crawl spaces beneath your bungalow, the detached workshops on your acreage property, and the particular way Portland’s 144-day rain cycle attacks ductwork from the outside in. Call (877) 335-1974 for a free estimate — we’ll dispatch from our Seattle base with owner-led crews who’ve handled Portland’s moisture-laden conditions for 11 years.
Our Duct Repair & Sealing team knows the difference between a quick patch and a repair that survives Portland’s marine-layer humidity. Richard Anderson oversees every job personally, whether we’re sealing metal plenum leaks in a Kenton foursquare or replacing collapsed flex duct in a West Hills workshop.
Why Landmark Air Duct Cleaning Service Washington Is Portland’s Preferred Duct Repair & Sealing Company
We’ve earned our reputation in Portland through 732 verified reviews averaging 4.9 stars — a volume that reflects hundreds of real homes across the metro, from Raleigh Hills ranches to SE Portland Craftsman bungalows. Portland customers consistently mention the same things: Richard Anderson showed up himself, diagnosed the actual problem (not just the symptom), and fixed it without needing a return trip.
That owner-led accountability matters especially here. Portland’s housing stock — dense with pre-1945 bungalows and foursquares in ZIP codes 97201–97210 — presents duct configurations that rotate crews simply don’t encounter often enough to read correctly. Richard’s 11 years of exclusive air-duct focus means he’s seen the undersized galvanized retrofits, the 1970s flex-duct collapses, and the mold-saturated crawl-space runs that define Portland’s older neighborhoods.
Response time to Portland averages same-day or next-day, depending on whether we’re routing from our Seattle base or coordinating with scheduled stops in Kenton or West Haven-Sylvan. We carry Rotobrush and Nikro professional-grade equipment plus mastic sealants rated for Pacific Northwest humidity, so we’re not making supply runs mid-job.
Portland’s market has plenty of generalist HVAC companies that added duct sealing as an upsell. We’re the opposite — a dedicated indoor-air-quality specialist where duct repair is core work, not a sideline. That distinction shows up in how we assess crawl-space moisture before sealing, how we spec insulation for 144-day rain exposure, and how we warranty our work.
Our Duct Repair & Sealing Services in Portland
Duct Sealing
Leaky ducts in Portland homes don’t just waste energy — they pull crawl-space moisture and mold spores directly into your living air. We seal supply and return plenums with mastic sealant rated for marine-layer conditions, then pressure-test to verify closure. In SE Portland bungalows off Division Street, we regularly find original galvanized trunk lines with separated seams that have been leaking for decades; our sealing restores design airflow without tearing out walls.
For detached workshops on acreage properties in outer East County or the West Hills, we seal duct runs independently from the main house system. These outbuildings often have heavier-duty equipment and irregular usage patterns that standard residential approaches miss.
Flex Duct Repair
Flex duct in Portland’s crawl spaces faces a brutal combination: chronic humidity from 37+ inches of annual rainfall, plus the temperature differentials of unconditioned spaces. The result is jacket degradation, internal liner collapse, and active mold colonization — sometimes all three simultaneously.
In a SE Portland bungalow off Division Street, we replaced a collapsed flex-duct run through a damp crawl space where moisture had eaten through the jacket; we sealed the remaining metal plenum with mastic and installed a new insulated flex line from Rotobrush that can handle the 144-day rain cycle. That job took one trip because Richard assessed moisture source and duct replacement together — not as separate visits.
Metal Duct Repair
Galvanized sheet metal in Portland’s pre-1960 homes corrodes from the outside in, where crawl-space moisture condenses on cold duct surfaces. We repair separated seams, patch rust-through sections, and rehang sagging trunk lines. Where metal has reached end of life, we transition to insulated flex with proper vapor barriers — a repair strategy that accounts for Portland’s humidity rather than ignoring it.
Duct Insulation & Mastic Sealant
Insulation in Portland crawl spaces must do two jobs: prevent condensation on cold air supply ducts, and resist moisture absorption from ambient humidity. We specify closed-cell or properly jacketed insulation materials that won’t become mold substrates. Our mastic sealant application includes full surface prep — we don’t seal over active mold or damp metal, because Portland’s humidity will defeat that bond within a season. We address the moisture source first, then seal.
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.
Trusted Brands We Service in Portland
We work with professional-grade equipment and products from Rotobrush and Nikro for duct cleaning and repair prep, and we specify air quality components from Honeywell, Aprilaire, and Abatement Technologies when your repair project includes filtration or sanitizing upgrades. For Portland’s moisture-challenged crawl spaces, we stock Guardsman-treated materials where appropriate. Parts availability means faster turnaround on your repair — we’re not waiting on Seattle supply runs to finish a mastic seal job in Kenton or Raleigh Hills.
Common Duct Repair & Sealing Problems We See in Portland Homes
- Mold-saturated flex duct in SE Portland bungalows. The combination of vented crawl spaces and 144-day rainfall creates near-permanent dampness. Flex duct installed in the 1970s–80s is often simultaneously coated in mold and partially collapsed from moisture-related material breakdown — routine here, almost unheard of in Bend or Medford.
- Failed mastic bonds from moisture-blind sealing. Competitors seal ducts without addressing the chronic crawl-space humidity source. In Portland, those bonds fail within a season. We assess moisture first, then seal.
- Undersized galvanized retrofits in pre-1945 homes. Portland’s inner ZIP codes are packed with Craftsman bungalows and foursquares that received forced-air systems decades after construction. Ducts are irregularly routed, frequently too small for modern equipment, and corroding from external condensation.
- Workshop airflow imbalance on acreage properties. Upgrading a workshop’s door springs or opener without verifying the ductwork to the shop is sealed leads to wasted energy and poor temperature control. We treat outbuilding ducts as independent systems requiring separate assessment.
Pricing for Duct Repair & Sealing in Portland, OR
Most residential duct sealing jobs in Portland run $280–$480 for accessible trunk lines and plenums. Flex duct replacement through a crawl space typically falls between $340–$650 per run, depending on length and whether we need to address active mold remediation first. Metal duct repair — seam sealing, patch work, rehanging — generally ranges $220–$420. Full duct insulation replacement in a crawl space runs $450–$890 depending on square footage and vapor-barrier specifications.
What moves you within these ranges: accessibility (crawl space height and condition), extent of moisture damage, whether mold remediation precedes sealing, and whether we’re coordinating with other indoor-air-quality work. Acreage properties with detached workshops may require additional line-item pricing for independent system assessment.
We provide upfront, itemized estimates before any work begins. Call (877) 335-1974 — estimates are free, and Richard Anderson will walk your specific situation personally.
We Also Serve Cities Near Portland
Our service radius includes Kenton, Raleigh Hills, West Haven, and West Haven-Sylvan — communities where we regularly encounter the same moisture-challenged crawl spaces and pre-war housing stock that define Portland’s duct repair needs. Whether you’re in a Kenton foursquare or a West Hills acreage property, the same owner-led crew handles your job.
Serving Portland, OR — Our Local Coverage Area
We’re based in the Portland 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 Portland
Yes — detached workshops on Portland acreage properties should be treated as independent duct systems with their own sealing assessment. We regularly find that workshop ducts leak significantly more than main-house runs due to longer exposed paths and less frequent maintenance, and sealing them separately prevents airflow imbalance that wastes energy. Call (877) 335-1974 to schedule a workshop-specific assessment — estimates are free.
Portland’s marine-layer humidity and 144-day rainfall cycle will degrade mastic bonds applied over damp or mold-active surfaces within one season. We always address crawl-space moisture sources and verify surface dryness before applying sealant, and we specify humidity-rated mastic formulations designed for Pacific Northwest conditions. For a lasting seal in your Portland home, call (877) 335-1974 — we warranty our prep work.
Closed-cell insulation with a robust vapor barrier performs best in SE Portland’s chronically damp crawl spaces, where standard fiberglass absorbs ambient moisture and becomes a mold substrate. We specify materials rated for exterior-grade humidity exposure, not residential lightweight products that fail in this environment. Call (877) 335-1974 and we’ll assess your specific crawl space conditions.
Collapsed flex duct requires full replacement — the internal wire helix and liner are structurally compromised and cannot be restored to design airflow. In Portland’s moisture-saturated crawl spaces, we also trace the moisture source to prevent repeat failure, then install new insulated flex rated for humid conditions. Call (877) 335-1974 for same-week replacement scheduling.
No — heavy-duty doors on Portland acreage workshops require opener and spring specifications matched to actual door weight and cycle frequency, not standard residential hardware. We verify load requirements and coordinate with any workshop duct sealing to ensure your HVAC system isn’t compensating for an improperly sealed space. Call (877) 335-1974 for owner-led assessment of your workshop setup.
Ready to fix your Portland home’s duct leaks for good? Richard Anderson and our owner-led crew are scheduling now across Portland, Kenton, Raleigh Hills, and West Haven-Sylvan. Whether you’re dealing with mold-saturated flex duct in a SE Portland crawl space or need your acreage workshop’s system sealed independently, we’ll diagnose the actual problem and fix it in one trip. Call (877) 335-1974 today for your free estimate.
Written by Richard Anderson, Owner and Lead Technician at Landmark Air Duct Cleaning Service Washington, serving Portland since 2014.