Duct Sealing in Baltimore - Tested First, Written Price Second

Fast, Reliable Duct Sealing Across Baltimore

Baltimore Duct Sealing typically runs $800 – $2,400 for a whole-home system, with most rowhouse jobs landing between $1,200 and $1,800 depending on whether we’re sealing accessible basement trunk lines or chasing leaks through shared party-wall chases. We dispatch from our Baltimore office and serve neighborhoods from Federal Hill to Hampden to Canton, usually scheduling within a week and arriving inside our quoted window. Call (361) 326-5060 for a free written estimate before any work starts.

Call (361) 326-5060

Baltimore’s housing stock is unlike anywhere else in the country. The 19th-century rowhouse corridors that define this city, from Fells Point to Station North, share wall cavities that original galvanized ductwork often runs through. That means duct sealing here frequently begins with camera inspection of party-wall chases that leak conditioned air directly into neighboring units. Because those same cavities once vented coal furnaces, gaps at floor registers in Hampden and Federal Hill can pull legacy coal ash into the supply stream, making sealing in Baltimore as much about cross-unit containment as efficiency. Our Duct Sealing crews are trained for exactly this reality.

Why Hollis Air Duct Cleaning Is Baltimore’s Preferred Duct Sealing Company

We’ve been part of the Garrison Partners family since 2004, and our Baltimore operation runs on The Garrison Standard: written prices, written guarantees, and a 365-Day Done Right Promise that competitors rarely match in writing. Our technicians are background-checked and uniformed, and our phones are answered by a live person 24 hours a day, seven days a week. No voicemail loops. No callback queues.

Our Baltimore customers come back because we price the job before we touch it, and that price doesn’t move at the door. The 365-Day Done Right Promise means if our sealing work fails within a year, we return and make it right at no charge, including a free second visit. We’ve earned our reputation in this city by showing up squared away and leaving sites clean.

We know the local conditions that break ductwork here: the humid subtropical summers that make ducts sweat and harbor mold, the freeze-thaw cycles that crack poorly insulated runs, and the restricted parking and narrow basement access that come with rowhouse living. Our crew coordinates dispatch from the brand’s Baltimore office, and we serve Baltimore with equipment sized for tight urban jobs.

HVAC Duct Sealing in Baltimore

HVAC Duct Sealing in Baltimore addresses the pressurized leaks that force your air handler to run longer, push utility bills up, and pull unfiltered basement or wall-cavity air into your supply stream. In a typical Baltimore rowhouse, we find 20 – 35% of conditioned air never reaches the rooms it’s supposed to serve. Instead it escapes through gaps at plenum connections, register boots, and the longitudinal seams of original galvanized trunk lines. Our process starts with a pressure test to quantify the leakage, followed by camera inspection of inaccessible runs, then mechanical cleaning of joints before we apply mastic and reinforced mesh. Sealing supply and return ducts without addressing the floor-register gaps common in Hampden rowhouses leaves the largest leakage path open, so pressure imbalances and neighbor odors persist. We close those gaps too.

When Sealing Becomes a Containment Job

We were called to a Federal Hill rowhouse where the upstairs bedroom smelled like the neighbor’s kitchen every time the air handler ran. Camera inspection showed a 2-inch separation in the original galvanized return trunk inside the shared party-wall chase, so we sealed the joint with mastic and mesh while running negative pressure to keep dust out of the living space. After we rebalanced the registers and verified with a smoke test, the cross-unit odor was gone and the blower motor was no longer short-cycling. This is standard work for us in Baltimore’s attached housing.

Mastic Over Dirty Joints Won’t Hold

Mastic and mesh applied over dirty galvanized joints in shared-wall chases fail within a season because coal-era dust and plaster grit prevent adhesion. Our source removal and agitation tools clean the substrate first. We use Rotobrush rotary systems and Nikro negative-air machines to prep the surface, then seal with products that bond to bare metal. The job lasts.

Duct Repair in Baltimore

Duct Repair in Baltimore fixes what sealing alone cannot: crushed flex runs, disconnected collars, rusted-out galvanized sections, and pest damage in crawlspace trunks. We see a lot of this in the unheated basements and narrow crawlspaces beneath Baltimore’s rowhouses, where decades of moisture exposure have corroded original metalwork. Repair costs in Baltimore typically range from $400 for a localized collar replacement to $1,500 for trunk-line section replacement in tight access conditions. We always inspect with a camera first, so you know exactly what failed and why before we quote the fix.

Replacing Failed Sections

When galvanized trunk lines have rusted through or flex duct has been chewed by rodents in a Canton crawlspace, we cut out the damaged section and splice in new material rated for the application. We match the gauge and diameter to maintain system balance. Every repair is pressure-tested before we leave.

Register Boot Rebuilds

The floor registers in older Baltimore homes often sit in rotted or detached boots that leak into the wall cavity below. We rebuild or replace these boots, seal them to the subfloor, and verify with a smoke pencil. It’s tedious work in tight quarters, but it’s what stops the basement smell.

Trusted Brands We Service in Baltimore

We carry professional-grade equipment from Rotobrush, Nikro, and Abatement Technologies, and we stock filtration and sealing products from Honeywell, Aprilaire, and Guardsman, plus we can handle Lennox repair in Baltimore. For Baltimore customers, that means we don’t wait on parts shipped from out of state. Our van inventory includes mastic, reinforced mesh, collar hardware, and register boots sized for the original ductwork common in local rowhouses. When we find a failed component during inspection, we can usually repair it same visit. The tools we use are the same ones commercial crews deploy in hospitals and schools, and we’ll explain what each one does while we’re working in your home.

Common Duct Sealing Problems We See in Baltimore Homes

• Shared-wall chase leakage: In rowhouse corridors from Hampden to Patterson Park, original ductwork runs through party-wall cavities that were never designed for airtight HVAC. We camera-inspect these chases and seal separation points that leak air, and sometimes odors, between units.
• Coal-dust contamination at registers: Gaps at floor registers in pre-1950s homes pull legacy coal ash and basement dust into the supply stream when the blower kicks on. Sealing the register boot to the floor and the duct to the boot stops this.
• Summer mold in sweating ducts: Baltimore’s humid subtropical climate means uninsulated or poorly insulated ductwork in unconditioned spaces sweats heavily from June through September. We seal the leaks that draw humid air in, and we flag insulation gaps that need addressing.
• Dryer vent stacks defeating nearby sealing work: Ignoring the dryer vent stack shared through Baltimore rowhouse walls means lint builds in an inaccessible run, creating both a fire risk and a backdraft that defeats nearby duct sealing work. We inspect these runs and recommend proper independent venting where code allows.

Pricing for Duct Sealing in Baltimore, MD

We Also Serve Cities Near Baltimore

Our crews work throughout the Baltimore metro, including Duct Sealing in Baltimore proper and the surrounding communities of Catonsville, Rosedale, Dundalk, and Parkville. Scheduling and dispatch are coordinated from our Baltimore office. Whether you’re in a Catonsville split-level with crawlspace access issues or a Dundalk rowhouse with shared-wall concerns, we bring the same written pricing and 365-Day Done Right Promise.

FAQs About Duct Sealing in Baltimore