Level 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 Fairfax Owner’s Guide
We stock and install Gelco-compatible flue liner replacement parts for Fairfax homes, with most full relines running between $2,400 and $4,800 installed depending on flue height and access. We carry common Gelco liner diameters on our trucks, so many Fairfax replacements are done in a single visit. Most owners discover the problem either during a chimney sweep when the camera shows cracking, or after noticing flue tile fragments in the firebox. You won’t feel a liner failing from the living room. You’ll see it on camera, or you’ll see the debris. The camera tells you what the chimney is; the written quote tells you what the fix costs. Everything else is just conversation.
Key Takeaways
- Gelco flue liner replacement in Fairfax runs $2,400 to $4,800 installed, and we quote it in writing before any work starts.
- We stock standard Gelco diameters on the truck and identify what you need by camera scan and measurement, not guesswork.
- A failed liner is a fire and carbon monoxide risk, not just a nuisance. We document what we find with photos before recommending anything.
- Every Gelco replacement includes a Level 2 camera inspection, written scope, written warranty, and a documented photo record when we’re done.
Which Gelco Models This Applies To

Gelco makes stainless steel flue liners in diameters from 4 inches up through 12 inches, in both smooth-wall and corrugated profiles. Most Fairfax fireplaces and furnaces we service use either the 6 inch or 8 inch diameter, though smaller wood stoves sometimes take a 5.5 inch liner and larger open fireplaces can run 10 to 12 inches. The compatibility gotcha most owners miss is the appliance collar size: your stove or furnace has a specific outlet diameter, and the liner needs to match it, not the old clay flue’s measurement. A stove with a 6 inch outlet vented into an 8 inch clay flue still needs a 6 inch Gelco liner, plus an insulated wrap if clearance to the masonry is tight.
Gelco liners are sized by inside diameter and sold in lengths matched to your flue. To identify what you have, look for the metal tag attached to the liner top plate at the chimney crown, or check the original install paperwork if it came with the house. Most Fairfax homes we service don’t have that paperwork, which is why we camera-scan and measure before quoting. On OEM versus aftermarket: Gelco is a mid-market liner brand that holds up well for typical VA wood-burning use. We install Gelco liners where the appliance and flue size suit them, and we also stock DuraFlex and HeatShield for cases where a heavier-gauge or hybrid system is the better call. We’re an independent service provider in Fairfax, not affiliated with Gelco, so our recommendation is based on what measures correctly and lasts, not brand loyalty.
Before
AfterSigns Your Gelco Flue Liner Replacement Is Failing
- Rust streaks or pinholes visible on the liner surface. Gelco liners are 316L stainless in most cases, but condensation from high-efficiency gas appliances creates acidic moisture that eats through thinner gauges over time. We see this most often in Fairfax colonials where the furnace was upgraded but the flue wasn’t.
- Flue tile fragments or metallic flakes in the firebox or cleanout. That’s not always the liner itself. Sometimes it’s the old clay tiles spalling behind it. Either way, something structural is shedding and it needs a camera to know which.
- Smoke backing into the room during startup. Cold flues draw poorly, which is normal for the first few minutes. If it persists or gets worse year over year, the liner may be partially collapsed or separated at a joint.
- A sulfur or chemical smell near the furnace or water heater. Exhaust gas escaping a cracked liner joint. Carbon monoxide travels with it. This one is not a “wait and see.”
- Visible gaps or separation at the liner seams. Gelco liners are joined with rivets or a locking seam depending on series. If a seam opens, hot gases hit the masonry directly, and the liner stops doing its job.
Replacement Cost & What’s Included

In Fairfax, a Gelco flue liner replacement typically runs $2,400 to $4,800 installed. The spread comes down to flue height (two-story homes cost more than single-story), roof pitch and access difficulty, whether we’re removing a failed liner first, and whether insulation wrap is needed for clearance. A straightforward one-story reline with a 6 inch Gelco liner tends to land near the bottom of that range. A two-story Fairfax colonial with a steep roof, a failed liner to extract, and an insulated wrap will land at the top.
| What’s Included | Notes |
|---|---|
| Level 2 camera inspection before work | We document the current liner condition in photos before pricing anything |
| Written scope and price | Delivered before work starts, never after. Haven Standard Clause 1. |
| Gelco liner, cut and fitted to your flue | Correct diameter and length, not a one-size attempt |
| Top plate, rain cap, and connector if needed | All quoted line-item so you see what each part costs |
| Documented photo record on completion | Every job since 2009. Haven Standard Clause 4. |
| Written warranty | Statement of what’s covered and for how long, in writing before work begins |
Our pricing is flat and written. You’ll see the liner cost, the labor, and any access equipment line by line. If you already have a written estimate from another Fairfax chimney company, bring it to us. We’ll give you a Free Second Opinion on that quote, no charge.
DIY or Call Us?
What you can safely do yourself: look inside the firebox for debris, check the cleanout door at the base of the chimney for accumulated material, and note any smell or discoloration around the furnace flue connection. That tells you something changed. It doesn’t tell you the cause.
What you shouldn’t attempt is pulling a liner or replacing one. A failed liner means combustion gases are getting where they shouldn’t be. Working on a chimney also means roof work, often on Fairfax roofs with pitches that make a ladder feel honest. High-angle work, hot flue gases, and carbon monoxide exposure are all part of the job. This is not a part where watching a video and saving money on labor pays off. If your Gelco liner is suspect, call us at (571) 443-8256. We’ll camera-scan it, show you the photos, and hand you a written price. If the liner has life left, we’ll tell you that too and you keep your money.
FAQs

A Gelco liner installed for wood burning in a Fairfax chimney typically lasts 15 to 20 years with regular sweeping, though that drops to 10 to 15 when venting a gas appliance without proper insulation. The real variable is condensation: Virginia’s humid shoulder seasons mean more moisture in the flue, and a liner that never gets hot enough to dry out fails from the inside first. When we camera-scan a liner, we’re looking at wall thickness and seam integrity, and we can usually tell if you’re looking at years versus months. Call (571) 443-8256 and we’ll put you on the schedule for a Level 2 scan with photos.
Sometimes a single seam can be re-secured, or a short section replaced, if the rest of the liner measures within spec. That’s the exception, not the rule. Most Gelco liners we see in Fairfax fail by thinning across a wide area, not at one identifiable point. A camera scan tells us which situation you have, and the written quote tells you the cheapest honest fix. We won’t recommend a full reline if a section repair is safe. We also won’t patch a liner that should be replaced and call it good.
Most Fairfax relines are done in one day, typically 4 to 6 hours. That includes removing the old liner, dropping the new Gelco liner, securing the top plate, connecting the appliance, and running a final camera scan to document the install. If the job requires scaffolding or the roof pitch demands extra rigging, it may run a second day. We’ll tell you that in the written scope before we start, and that timeline is part of the written warranty.
We carry common 5.5 inch, 6 inch, and 8 inch Gelco liners on our trucks, along with connectors, top plates, and rain caps. If you need a less common diameter or a specific length we don’t have on hand, it’s usually one to two days to source. That’s part of why we camera-scan and measure first, so we arrive on install day with the right liner. No ordering after we tear things apart. Call (571) 443-8256 for a written estimate.
Written by Corrine Halstead, Owner, Level Two Chimney Fairfax at Level Two Chimney Fairfax, serving Fairfax and nearby areas.





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