Masonry repair
Sweep & inspection
Caps & crowns
Flue relining
Gas fireplace serviceLevel 1 sweep and inspection to the NFPA 211 annual standard - flue, crown, cap, and flashing checked and photographed
Chimney sweep logs do not sweep chimneys. They loosen some creosote - which then falls where a brush and vacuum still have to collect it.
Gelco Damper Repair: The San Antonio Owner’s Guide
We stock and install Gelco-compatible damper repair parts across San Antonio, with most top-sealing damper swaps running $340 – $620 installed, depending on flue size and access. If your Gelco damper has seized, the cable has snapped, or the plate won’t seal, you’ll typically notice it as a draft in the living room, a faint smoky smell after a fire, or rainwater streaking down the firebox walls. Most owners catch it the first cold front of fall, when the house won’t hold heat and the fireplace starts acting like an open window.
Which Gelco Models This Applies To
Gelco dampers fall into two main lines: the older cable-operated top-mount models and the newer lever or worm-drive series found on many pre-fabricated fireplaces in San Antonio neighborhoods like Stone Oak, Alamo Heights, and Helotes. The compatibility gotcha is the control handle: Gelco changed the cable housing diameter between generations, so a handle from a 1990s unit won’t thread onto a cable made after 2010, even if the damper plate itself looks identical.
To identify yours, look inside the firebox for a Gelco label or a stamped serial prefix on the damper frame. If the label is gone, measure the flue opening across the narrowest point: Gelco dampers are built for 8-inch, 10-inch, and 12-inch flues, and a plate that’s even half an inch off will never seal correctly. We install genuine Gelco components when the unit is still under a manufacturer warranty, and we carry equivalent aftermarket hardware when it isn’t. In our experience the aftermarket plates and cables hold up just as well for San Antonio’s climate because the failure is almost never the metal itself. It’s the cable, the silicone blade edges, or the mounting hardware.
Styles & brands we work with





Signs Your Gelco Damper Repair Is Failing
- The handle spins without resistance. This usually means the cable has snapped inside the conduit or detached from the damper plate. The handle feels dead because it’s no longer connected to anything.
- You feel a draft even when the damper is closed. Gelco plates seal against the flue rim with a flexible silicone edge. After eight to ten years of San Antonio heat cycling, that silicone hardens and shrinks, leaving a gap the damper can’t close.
- Rainwater streaks appear below the damper. A top-mount damper that won’t fully seat lets water run down the flue and into the firebox. You’ll see rust stains or water marks on the refractory panels.
- The damper sticks half-open or needs hard force to move. Creosote and Texas oak soot build up on the pivot points and the cable track, especially if the chimney hasn’t been swept in a few seasons.
- You smell smoke days after a fire. A damper that won’t close lets flue gases and the smell of cold ash settle back into the room. This one gets worse at night when the house cools and air pressure shifts.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
In San Antonio, a complete Gelco damper repair the way we do it runs $340 – $620 depending on whether we’re replacing just the cable and handle assembly or the full damper plate with a new mounting ring. The lower end covers a cable replacement and handle re-mount on a 8-inch flue; the upper end covers a new plate, new silicone seal, and hardware on a 12-inch flue where we have to work from the roof. Every quote includes parts, labor, and a written price before we touch anything, so you know the number before the work starts.
We only install materials we’d put in our own homes: genuine Gelco components when they’re the right call, or the equivalent trade-grade hardware from suppliers like DuraFlex and HeatShield when an aftermarket part is the smarter money. And every Gelco damper repair carries our 365-Day Done Right Promise: a written guarantee on the repair, and if it fails within the year, we come back and fix it free.
DIY or Call Us?
You can safely check two things when your Gelco damper won’t close. First, look up the flue with a flashlight for obvious obstruction like a bird’s nest or a creosote chunk jammed in the plate. Second, try moving the handle through its full range to feel whether the cable is attached or spinning loose. Beyond that, this is not a DIY job, and here’s why: the cable runs through a conduit up the flue, and replacing it usually means working from the roofline. That’s a fall hazard most homeowners shouldn’t take on with a ladder and a flashlight. The blade tension also matters, a plate that’s mounted slightly off-square will warp and fail again within a season.
If the handle spins free or you see water streaks, call us at (903) 515-5079 and we’ll bring the parts the first trip.
FAQs
Expect eight to twelve years from a Gelco top-mount damper in this climate. The silicone seal degrades faster in San Antonio’s heat than the steel does, and the cable routing through a clay tile flue tends to chafe where the conduit bends. Call (903) 515-5079 for a quote on a replacement that fits your flue size.
Yes, if the failure is the cable, the handle, or a fouled pivot, we repair the existing damper. If the silicone blade has hardened or the plate is warped, replacement is the honest call, because a patched seal will leak air and water again within a season or two.
Most Gelco damper repairs take 60 to 90 minutes from start to finish, including verifying the seal and testing the handle from inside the firebox. Jobs that require rooftop access on a steep pitch or a flue with internal obstructions can run longer, but we’ll tell you that before we start, not after.
We keep Gelco-compatible cables, handles, plates, and mounting hardware on the truck for the most common sizes in San Antonio homes: 8-inch, 10-inch, and 12-inch flues. Occasionally a specialty plate has to be ordered, and we’ll let you know the timeline before you commit to anything.
Written by Ruben Castellano, Owner, Alcott Chimney San Antonio at Alcott Chimney San Antonio, serving San Antonio and nearby areas.