Flue relining
Sweep & inspection
Caps & crowns
Masonry repair
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 Flue Liner Replacement: The San Francisco Owner’s Guide
We stock Gelco-compatible flue liner replacement parts and install them across San Francisco, typically for $1,400 to $2,600 including the liner, connectors, labor, and a written guarantee. Most Gelco liner replacements take one visit, roughly four to six hours, and we carry common sizes on the truck so there’s no second trip for parts. The way most San Francisco homeowners find out their Gelco liner has failed is a chimney inspection that shows cracked or separated stainless steel, often in the upper third of the flue where coastal moisture and years of heating cycles have done their quiet work.
You might not see smoke or smell anything unusual yet. That’s exactly why we recommend a camera inspection before anyone quotes you a replacement. In older San Francisco homes, a Gelco liner can fail internally while the exterior brick and cap look perfectly fine from the street.
Which Gelco Models This Applies To
Gelco manufactured rigid and flexible stainless steel chimney liners in a range of diameters, most commonly 5.5″, 6″, 7″, and 8″, and these are the sizes we see throughout San Francisco’s Victorian-era chimneys and mid-century prefab fireboxes. The compatibility issue that catches people off guard is this: a Gelco liner is matched to the appliance it vents, not just the flue opening it slides through. So a liner that physically fits down the chimney might be the wrong diameter for the furnace or water heater feeding into it.
When we arrive, we check the data plate on your appliance or the markings on the liner itself before matching a replacement. Gelco liners typically carry a stamp on the outer wall with diameter and grade. If that’s worn or inaccessible, we measure the inner diameter and confirm the appliance BTU rating. For Gelco specifically, we prefer a true 316L stainless steel replacement when the liner serves a gas appliance, because San Francisco’s fog and coastal air accelerate corrosion on lesser alloys. We also work with DuraFlex and HeatShield systems, so if your existing setup is a mixed-brand install or you’re weighing a full resurface instead of a liner swap, we can lay out both paths honestly.
Styles & brands we work with
Signs Your Gelco Flue Liner Replacement Is Failing
- Visible rust streaks or staining on the chimney exterior. This usually means moisture is getting through a corroded liner section and leaching out through brick or mortar. In fog-belt neighborhoods like the Sunset District, this shows up earlier than in drier parts of the city.
- Flakes of metal in the firebox or at the cleanout door. When a Gelco liner’s inner wall begins to delaminate, small pieces of stainless or coating break free and settle at the lowest point of the system. We find these during cleanings in homes near Alamo Square where the flues are long and steep.
- A smell like damp metal or exhaust in the room when the appliance runs. This points to a crack or separated seam letting combustion gases escape the liner before they reach the top of the chimney.
- Increased condensation on windows near the chimney or on the flue cap itself. Gas appliances produce water vapor. A healthy liner carries it out. A failed one lets it collect inside the flue, and in San Francisco’s already-damp air, that persistent moisture accelerates rust.
- The liner shows gaps or separation at the seams during a camera inspection. This is the most reliable sign, and it’s why we never recommend a liner replacement based on a visual-only roof check. We put a camera down the flue and show you exactly what we’re seeing on our screen before any work is quoted.
Replacement Cost & What’s Included
A full Gelco-compatible flue liner replacement in San Francisco runs between $1,400 and $2,600 installed. The range comes down to three things: liner length, diameter, and how much of the surrounding connector hardware needs replacing at the same time. A short 6″ liner on a one-story Outer Richmond bungalow lands near the bottom of that range. A 35-foot, 8″ liner serving both a furnace and water heater in a three-story Victorian near Noe Valley is closer to the top.
Every quote we give is a written, flat price before the job starts. It includes the liner itself, all necessary connectors and top plate, removal and disposal of your failed Gelco liner, installation, and a camera re-inspection afterward. We carry 316L stainless liners in the most common San Francisco sizes on our trucks, which keeps most jobs to one visit. The work is covered by our 365-Day Done Right Promise: if the repair fails within one year, the second visit is free. Gelco is not affiliated with Alcott Chimney San Francisco. We’re an independent service provider, so you get an honest read on whether you actually need a new Gelco part or a different solution entirely.
See the difference
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AfterDIY or Call Us?
Here’s the straight truth: flue liner replacement is not a handyman project, and it’s not a YouTube project. You’re working at height on a San Francisco roof, often on a steep pitch, handling 20 to 35 feet of stainless steel that can bind, kink, and tear the interior of your chimney if it’s not fed correctly. A liner that’s improperly connected or sized creates a carbon monoxide risk you can’t see or smell. This is one of those jobs where the cost of getting it wrong is too high to learn on your own house.
What you can do safely is look at the signs above and tell us what you’re seeing. Tell me what you’re seeing, and I’ll tell you straight what it means. We’ll send a background-checked, identity-verified technician, and you’ll know their name and see their photo before they arrive. If you’re not sure whether your Gelco liner has failed or just looks rough, call (831) 534-3789 for a camera inspection first. The estimate is free, and we’ll show you the footage before we recommend spending a dollar.
Frequently Asked Questions
A Gelco flue liner typically lasts 15 to 25 years, but San Francisco’s coastal moisture and fog can pull that toward the lower end if the liner is a lighter stainless grade or regularly exposed to a salt-air roof environment. Gas appliances run cooler and produce more condensation than wood, which also shortens liner life. If your liner is past year 20 and showing rust or seam separation, replacement is usually cheaper than waiting for a full failure. Call (831) 534-3789 and we’ll tell you whether yours has life left in it.
Small isolated damage can sometimes be addressed with a HeatShield resurfacing treatment rather than a full liner pull, but seam separation or corrosion in multiple sections usually means the liner has reached the end of its service life. The honest answer depends on what the camera shows: a single rust spot is one thing, a liner flaking along its entire length is another. When we inspect, we’ll show you the footage and tell you plainly whether repair buys you time or throws good money after bad.
Most Gelco liner replacements in San Francisco take four to six hours on site, including removal of the old liner, installation of the new one, and a camera re-inspection. If your chimney is especially tall or the roof angle is steep, plan for a longer visit. We book the job as a single-day appointment, and because we carry common liner sizes on the truck, most homeowners don’t wait through a second parts trip.
Yes, we carry 316L stainless flue liners in the most common San Francisco diameters, along with top plates, connectors, and termination caps, so most Gelco replacements happen in one visit. If your liner is a less common size or length, we’ll order the right piece and schedule the install once it’s in hand. We’ll never substitute a different size just to finish faster; the liner has to match your appliance’s BTU rating or it doesn’t go in.
Get an Honest Quote for Your Gelco Liner Replacement
If your Gelco liner is showing signs of failure, or you just want a professional camera inspection to know where you stand, call Alcott Chimney San Francisco at (831) 534-3789. Ruben Castellano and our crew have been serving San Francisco homeowners since 2002, and we’ll give you a written price before any work begins. You’ll know who’s coming, what you’re paying, and exactly what’s wrong with your liner before we touch a thing.
Written by Ruben Castellano, Owner, Alcott Chimney San Francisco, serving San Francisco and nearby areas.