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.
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Before
AfterDuraFlex Flue Liner Replacement: The Yonkers Owner’s Guide
DuraFlex flue liner replacement in Yonkers typically runs $1,850-$3,400 installed, depending on liner diameter, length, and whether the old liner needs to be broken out of a masonry flue. We stock DuraFlex 316L and AL29-4C liner kits on the truck and can usually complete a straight swap the same day we diagnose it. Most Yonkers homeowners discover the problem one of two ways: a Level 2 camera inspection that shows cracks, pitting, or separation at the liner seams, or a furnace or water heater that starts tripping rollout switches because the flue can’t draft. Either way, the fix is the same: get the right liner matched to the appliance, sized to the flue, and installed so the exhaust has nowhere to go but up.
Which DuraFlex Models This Applies To
DuraFlex makes two liner families we see in Yonkers homes, and they are not interchangeable. The 316L alloy liner is for natural gas and oil appliances, including furnaces, boilers, and standard water heaters. The AL29-4C liner is built for high-efficiency condensing appliances that produce acidic condensate, and it’s marked with a distinct blue or silver label at the collar. You can identify what you have by looking at the liner cap on the roof or the exposed section above the appliance: 316L will show a dull gray finish, AL29-4C will have a stainless band with the alloy printed on it. If you’re not sure which one you have, don’t guess. A mismatched alloy is a corrosion failure waiting to happen: 316L on a condensing furnace will pin-hole through in three to five years because it can’t take the acid. As for OEM versus aftermarket: DuraFlex is the OEM here, and we use their components because the seam locks and couplers are specific to the system. We’re an independent service provider, not a DuraFlex dealer, but we’ve found that generic aftermarket liner sections don’t always mate cleanly with existing DuraFlex couplers.
Signs Your DuraFlex Flue Liner Replacement Is Failing
- Exhaust smell in the basement or utility room. When the liner develops a crack or separation, combustion gases leak into the living space around the appliance instead of venting outside. This is not a smell to wait out; it means the liner has already opened up.
- Rust or water staining on the liner’s exterior. Condensation is a normal byproduct of gas combustion, but a cracked liner traps moisture against the metal. Over time, Yonkers humidity and roof runoff make this worse, especially in older chimneys without a rain cap.
- Furnace or water heater rollout trips. If the flame pushes out the front of the burner instead of drafting up the flue, the safety rollout switch shuts the appliance down. The appliance is doing its job; the liner is the problem.
- Crumbling or flaking at the liner seams. Look up from the appliance connection with a flashlight. If you see metallic flakes or gaps where sections join, the liner has started to de-laminate. This is what we find most often in homes along the Hudson River corridor, where salt air accelerates metal fatigue.
- Camera inspection shows Class III creosote or liner rust-through. Class III creosote is the heavy, baked-on, tar-like stage that can burn like fuel inside the flue. If the camera shows it built up on a liner that’s already showing rust, you need a replacement, not a sweep that’s going to leave you with a patched-up shell.
BeforeAfterReplacement Cost & What’s Included
For a straight DuraFlex liner swap in Yonkers, where we’re pulling the old liner out of a masonry flue and dropping a new one in, you’re looking at $1,850-$2,600 for a typical 4-inch or 5-inch gas liner up to 30 feet. A 6-inch liner for a larger furnace or a wood-burning fireplace insert runs $2,400-$3,400. Every quote includes the liner sections, couplers, rain cap, and top plate; the foam insulation wrap if your flue is oversized for the liner; and the labor to remove the old liner and verify draft with a camera before and after. What drives the range is height, roof pitch, and whether we need a lift or ladder access on a three-story Yonkers rowhome. Every job gets a written price and written scope before we start, and a photo record of the installed liner when we’re done. That’s Haven Standard Clause 1 and Clause 4, no exceptions.
DIY or Call Us?
You can check a few things yourself without touching the liner: look at the exposed section above the appliance for rust, shine a flashlight up from the thimble to spot seam gaps, and check whether the rain cap is still in place on the roof. From there, call us. Liner replacement involves disconnecting the appliance from the flue collar, pulling a metal liner out of a vertical masonry chase, and lowering a new one down without kinking or scraping it. A kinked liner can’t carry the draft and becomes a condensation trap; a torn liner section leaves you with the same leak you started with. This is also a job where the wrong alloy - 316L on a condensing furnace, say - can fail silently for years while feeding carbon monoxide back into the home. The camera doesn’t lie, and neither does the quote. If you’ve got a suspect DuraFlex liner in Yonkers, call (551) 212-3526 and we’ll run the camera first, name what we found, and put the price in writing before anything else happens.
FAQs
A 316L DuraFlex liner on a gas furnace in Yonkers usually lasts 15-20 years before pitting or seam fatigue starts to show on camera, while an AL29-4C liner on a condensing appliance typically runs 20-25 years. Roof runoff, salt air near the Hudson, and how often the appliance cycles all pull that number down. If your liner is past year 18, a camera inspection is the only honest way to know whether it’s still serviceable. Call (551) 212-3526 for an inspection and a written replacement quote if it’s time.
In most cases, no. Liners fail at the seams or from pinholes that can’t be effectively patched once corrosion has started; a section repair on a gas liner leaves you with a weak point at the coupling that fails again. If the liner is otherwise sound and the only issue is a loose joint or a missing rain cap, we can fix that. But if the camera shows rust-through or cracks along the liner body, replacement is the repair. We’ll show you the footage so you can see exactly what we’re seeing.
A straight DuraFlex liner swap in a typical Yonkers masonry chimney takes four to six hours from removal to final camera verification. Most jobs are done in a single day. If we have to remove the old liner that’s rusted or locked into the flue, or if the roof access is difficult, we’ll tell you that upfront in the written quote, so the timeline is on paper before we start.
We keep DuraFlex 316L and AL29-4C liner sections, couplers, top plates, and rain caps on the truck, so most replacements don’t require a second trip. We also carry HeatShield and Gelco materials for cases where a flue can be resurfaced instead of fully relined. If we need a specific size or length we don’t have on hand, we’ll have it in 24-48 hours and complete the job the same day it arrives.
Written by Corrine Halstead, Owner, Level Two Chimney Yonkers at Level Two Chimney Yonkers, serving Yonkers and nearby areas.