Fast, Reliable Duct Repair & Sealing Across North Hollywood
Duct repair and sealing in North Hollywood typically costs $180–$650 depending on whether we’re patching a single flex-duct joint or resealing an entire galvanized system, and most jobs are completed in a single visit. If you’re seeing uneven temperatures between rooms, dust pouring from vents, or your energy bill climbing through another Valley summer, the problem is almost always leaking or deteriorating ductwork — not your HVAC unit itself.
We work all across North Hollywood, from the post-WWII bungalows near Tujunga Avenue to the classic 1960s dingbat apartments off Lankershim Boulevard and Vineland Avenue in the 91605 and 91606 ZIP codes. Richard Anderson, owner and lead technician at Landmark Air Duct Cleaning Service California, personally handles every duct repair and sealing job we take on — you’ll never get handed off to a subcontractor crew you’ve never met. We’ve spent 14 years focused specifically on air duct systems, and we know how North Hollywood’s unique combination of aging housing stock and brutal Valley heat destroys ductwork faster than almost anywhere else in Los Angeles County. Call (833) 958-5022 for a free estimate — we’ll show up when we say we will, diagnose the actual problem, and give you upfront pricing before any work starts.
Why Landmark Air Duct Cleaning Service California Is North Hollywood’s Preferred Duct Repair & Sealing Company
Our Duct Repair & Sealing team has built a 4.9-star average across 364+ verified customer reviews — and a significant share of those come from repeat North Hollywood homeowners and property managers who’ve learned they can count on Richard to show up personally and fix the problem without upselling. We’re not a franchise operation cycling through different technicians every season; Richard has been the same face on every job for 14 years.
Response time to North Hollywood is typically same-day or next-day because we’re based in nearby Bell, CA — close enough to reach the 91605, 91606, 91609, and 91611 ZIP codes quickly without the scheduling delays you get from companies dispatching from the Westside or Orange County. We know the local building stock: the original galvanized sheet-metal ducts in 1950s Valley Village cottages, the accordion flex runs in 1960s Toluca Woods apartment buildings, the retrofit challenges in NoHo Arts District lofts. That local knowledge means faster diagnosis, fewer return trips, and repairs that actually last through the next heat wave.
Our equipment reflects our focus. We run professional Rotobrush and Nikro systems — the same rotary brush and negative-air extraction tools used by commercial restoration contractors — not consumer-grade shop vacs with HEPA attachments. When we’re sealing ductwork, we use industrial-grade mastic and proper application techniques, not foil tape that’ll peel off by August.
Our Duct Repair & Sealing Services in North Hollywood
Mastic Sealant Application
In North Hollywood, mastic sealant is often the difference between an efficient HVAC system and one that’s bleeding 20–30% of its conditioned air into attics and crawlspaces. Here’s the local reality: the combination of post-WWII galvanized ductwork and the Valley’s high summer heat load causes mastic sealant to dry out and crack within 2–3 years rather than the typical 5–7, making annual sealing inspections critical. We apply mastic by hand to every accessible joint, collar, and seam, then verify with pressure testing where appropriate. For the older systems common in 91605 and 91606, we often find original installations that were never sealed at all — just raw metal joints that have been leaking for decades.
Flex Duct Repair
Flex duct in North Hollywood’s 1960s–70s dingbat apartments is almost always past its service life. The insulation degrades, the wire helix corrodes, and the accordion sections sag between supports until they collapse entirely — sometimes blocking airflow completely, sometimes tearing open to dump cooled air into the attic. We recently repaired a collapsed flex duct in the attic of a 1960s dingbat apartment on Lankershim Boulevard in 91605. The original accordion flex had separated at the joint, dumping conditioned air into the crawlspace, while the return plenum was clogged with the telltale reddish-gray Valley dust. We replaced the damaged section with new insulated flex duct and applied mastic sealant to all accessible joints, restoring airflow and reducing the tenant’s electric bill by roughly 15%.
Metal Duct Repair
Original galvanized metal duct joints in North Hollywood’s post-WWII homes corrode and separate after decades of exposure to high heat and airborne particulates, causing massive air leaks. We can often repair these systems rather than replace them — resealing joints, patching small corrosion holes with proper metal patches and mastic, and reinforcing weak supports. Replacement only becomes necessary when the metal itself has thinned to the point of structural failure or when the original design is so poorly configured that no amount of sealing will deliver even airflow. Richard will tell you straight which situation you’re in.
Duct Insulation
North Hollywood attics hit 140°F+ in summer. Uninsulated or degraded duct insulation means you’re paying to cool air that heats back up before it reaches your vents. We replace damaged insulation with proper R-rated materials, paying special attention to flex duct runs that pass through unconditioned attic spaces — a common scenario in the single-story ranch homes near Magnolia Boulevard and the apartment conversions in the NoHo Arts District.
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 North Hollywood
We stock parts and service components from Honeywell, Aprilaire, and Abatement Technologies — brands that hold up under the demanding conditions we see in North Hollywood. Honeywell media air cleaners and Aprilaire humidifier components integrate directly with the ductwork we’re sealing, so we can address air quality and leakage in the same visit. For property managers with multiple units in the 91605 and 91606 ZIP codes, this means one vendor relationship instead of separate calls for duct repair and IAQ equipment. We don’t have to order parts from a warehouse two counties away — we carry the common fittings, collars, and sealants on the truck, which keeps turnaround tight and your tenants comfortable.
Common Duct Repair & Sealing Problems We See in North Hollywood Homes
- Original galvanized metal duct joints corrode and separate after decades of exposure to high heat and airborne particulates, causing massive air leaks. We find this constantly in the 1950s-era homes between Victory Boulevard and Oxnard Street — metal that was never properly sealed in the first place, now rusted through at the seams.
- Flex duct in 1960s–70s dingbat apartments sags and collapses at supports due to degraded insulation, blocking airflow entirely. The heat in North Hollywood attics accelerates the breakdown of the plastic vapor barrier and fiberglass insulation, leaving the wire helix exposed and eventually kinked.
- Mastic sealant applied to older ductwork in North Hollywood fails prematurely because the extreme summer heat accelerates drying and cracking. A seal job that might last six years in Santa Monica needs checking every two to three years here — it’s not poor workmanship, it’s physics.
- Return-air plenums packed with reddish-gray Valley dust — a distinctive mix of desert soil, smog particulates, and degraded flex-duct insulation that we see in nearly every older North Hollywood apartment we open up. This debris restricts airflow, strains the blower motor, and recirculates fine particles every time the system cycles.
Pricing for Duct Repair & Sealing in North Hollywood, CA
Here’s what duct repair and sealing actually costs in the North Hollywood market:
| Service | Typical Range |
|---|---|
| Single flex duct section repair/replacement | $180–$320 |
| Mastic sealant — partial system (up to 10 joints) | $220–$380 |
| Mastic sealant — full system reseal | $450–$650 |
| Metal duct patch and reseal (per section) | $200–$350 |
| Duct insulation replacement (per linear foot) | $8–$14 |
| Return plenum cleaning and reseal | $280–$420 |
What moves you up or down within these ranges: accessibility (crawlspace vs. walk-in attic), extent of corrosion or damage, whether we need to remove and replace versus seal in place, and whether the system needs cleaning before we can properly seal it. We don’t quote over the phone for repairs — we need to see the actual ductwork, because two “1960s dingbat apartments on Vineland” can have completely different conditions. Estimates are free, detailed, and delivered on the spot. Call (833) 958-5022 to schedule.
We Also Serve Cities Near North Hollywood
Our service area extends naturally from our Bell base into the full San Fernando Valley and adjacent communities. We regularly handle duct repair and sealing calls in Studio City (similar vintage housing with hillside access challenges), Universal City (condo and rental properties with compact attic spaces), Burbank (mix of historic homes and newer construction with different duct standards), and Valley Glen (dense apartment stock with the same dingbat-era flex duct issues we see in North Hollywood). If you’re in these areas and dealing with leaking ducts, rising energy bills, or uneven cooling, we cover you with the same owner-led service.
Serving North Hollywood, CA — Our Local Coverage Area
We’re based in the North Hollywood 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 North Hollywood
The extreme and sustained heat in the San Fernando Valley — attic temperatures regularly exceeding 140°F for months at a stretch — accelerates the curing and eventual cracking of mastic compounds that would remain flexible for years in milder climates. In North Hollywood specifically, the mountain-ringed basin traps heat and extends the cooling season from April into late October, giving duct systems far more annual thermal cycling than coastal LA. We recommend inspection every two to three years rather than the five-to-seven-year interval that works in cooler areas. Call (833) 958-5022 to schedule a seal check — estimates are free.
Many original galvanized systems in North Hollywood can be repaired if the metal itself is still structurally sound — we reseal joints, patch isolated corrosion, and reinforce supports. Replacement becomes necessary only when the metal has thinned to the point of collapse or when the original design is so poorly routed that no repair will deliver balanced airflow. Richard Anderson evaluates each system in person and will tell you straight which path makes sense for your budget and your home’s layout. Call (833) 958-5022 for an honest assessment.
Sagging flex duct in 1960s North Hollywood apartments almost always indicates degraded insulation and a compromised wire helix — temporary fixes like zip-tying it back up won’t last through the next heat wave. We replace the damaged section with new R-8 insulated flex duct, properly support it at code-required intervals, and seal all joints with mastic. For multi-unit buildings, we coordinate with property managers to minimize tenant disruption. Call (833) 958-5022 — we know these buildings and can quote accurately after a quick attic inspection.
The reddish-gray dust is a mix of Valley desert soil, smog particulates from the 170/101 interchange, and degraded flex-duct insulation — it’s a visual indicator that your return system is pulling contaminated air and that your ductwork likely has leaks drawing in attic or crawlspace debris. This dust accumulation complicates sealing because we need to clean the surfaces for mastic to bond properly; we often pair duct cleaning with repair work in North Hollywood homes. The dust also means your filters are working overtime and your blower motor is straining. Call (833) 958-5022 and we’ll assess whether you need cleaning, sealing, or both.
Yes — filters catch only the largest particles, and wildfire smoke carries ultrafine particulates that pass straight through standard media and deposit deep in your duct system. After any nearby Verdugo Hills or Santa Susana fire event, filters can go from clean to completely blackened inside a week, a signal that smoke has already infiltrated the duct system and remediation is overdue before the next cooling season cranks up. We inspect return plenums and main trunk lines for soot deposition, check seals for smoke infiltration points, and clean or repair as needed to protect your indoor air quality. Call (833) 958-5022 for post-fire duct assessment — estimates are free.
Ready to stop losing conditioned air to your attic and start getting what you’re paying the utility company for? Call (833) 958-5022 now for a free, no-pressure estimate. Richard Anderson will show up personally, inspect your duct system, and give you straight answers about what needs fixing now, what can wait, and what it’ll cost. We’ve been keeping North Hollywood homes breathing clean and cooling efficiently for 14 years — let us show you why 364+ homeowners have rated us 4.9 stars.
Written by Richard Anderson, Owner at Landmark Air Duct Cleaning Service California, serving North Hollywood and the greater Los Angeles area since 2010.