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.
DuraFlex Chimney Liner & Rebuild in Baltimore: What to Know First
We provide independent DuraFlex chimney liner and rebuild service throughout Baltimore, with most jobs completed in a single visit and upfront pricing agreed before we start. A typical DuraFlex liner replacement runs $2,800 to $4,500 depending on flue length and accessibility, and we don’t recommend work you don’t need. If your DuraFlex liner is showing gaps, corrosion at the collar, or draft problems that started after a harsh winter, we’ll tell you straight what’s wrong and what it takes to fix it. Call (410) 849-6273 - a live person answers, 24 hours a day.
This page is for Baltimore homeowners with a DuraFlex stainless or flexible liner installed in the last 10 to 25 years, especially in older brick rowhouses from Canton to Hampden, where freeze-thaw cycles and original masonry settling test these systems harder than the manufacturer specs assume.
How DuraFlex Products Fail - and How We Fix Them
- DuraFlex SW (smooth-wall) liners crack at the flex-to-rigid transition collar. We’ve pulled dozens of these in Federal Hill and Fells Point homes where the collar weld failed after repeated expansion cycles. The fix isn’t a patch - we replace the collar with an OEM-grade stainless fitting or, when the homeowner prefers, a heavier-gauge aftermarket transition from Olympia Chimney that outlasts the original. We pressure-test before we leave.
- DuraFlex Pro liners corrode from the outside in when flue gases condense in unlined chimney cavities. Baltimore’s spring and fall temperature swings create more condensation cycles than southern climates, and we’ve seen Pro liners in Patterson Park-area homes lose wall thickness in under eight years. We pull the damaged section, inspect the surrounding masonry with our camera, and reinstall with proper insulation wrap to keep the flue warm enough to stay dry.
- DuraFlex flexible liners kink or ovalize during pulls in tight Baltimore flues. Old Baltimore chimneys, especially the narrow 8×8 flues common in pre-1950 rowhouses, don’t give much room. A kinked flex liner kills draft and traps creosote. We use a mandrel-sized pull head and, when needed, remove a course of interior brick rather than force the liner - the masonry goes back right, and the liner runs true.
- DuraFlex SW tee connections separate at the snout in heavily used woodstove installations. The tee takes the most thermal shock in the system. In homes near Lake Montebello where homeowners burn cordwood all winter, we’ve found tee snouts cracked clean through. We replace with a DuraFlex-compatible tee from our stock or a Gelco equivalent when the flue geometry demands it, and we reseal with high-temp silicone rated to 1,000°F - not the hardware-store stuff that cooks off in a season.
- DuraFlex liner top plates leak where they meet deteriorating crown mortar. This isn’t the liner’s fault, but it kills the liner. Water runs down the flue, pools at the bottom, and rusts out the connector. We fix the crown first with proper crown seal or rebuild, then reset the plate with a stainless storm collar - done right, so the fire takes care of itself.
Our DuraFlex Chimney Liner & Rebuild Process
- 1
Call and schedule. A live person answers, day or night. We ask what you’re burning, what you’re seeing, and when the liner was installed if you know. We book a Level-2 camera inspection, not a sales visit.
- 2
Camera inspection and photos. Our technician runs a camera the full length of your DuraFlex liner and the surrounding flue. You see the footage on a tablet. We explain what’s wrong, what caused it, and what happens if you wait. No verdict gets delivered without a picture to back it.
- 3
Parts decision - OEM or quality aftermarket. We stock DuraFlex-compatible components and equivalents from HeatShield, Gelco, and Olympia Chimney. If your warranty is still active and requires OEM, we source it. If not, we’ll recommend the part that solves the problem best, with no markup games.
- 4
The repair or rebuild. Our background-checked, uniformed techs complete most DuraFlex liner replacements and partial rebuilds in one day. We protect floors, contain dust, and work methodically - one thing at a time, no shortcuts.
- 5
Pressure test and draft check. Every liner gets a smoke test or pressure test depending on the job. We verify negative draft at the appliance and confirm no spillage. The numbers get noted on your invoice.
- 6
Cleanup, documentation, and guarantee. We leave the work area cleaner than we found it. You get photos, a plain-English summary, and our 90-Day Done Right Promise in writing - if it’s not right, we come back, no arguing.
What DuraFlex Chimney Liner & Rebuild Costs in Baltimore
These are real ranges for DuraFlex work we’ve completed in Baltimore neighborhoods from Roland Park to Highlandtown. Your exact estimate comes after inspection - and it’s free.
| Service | Typical Range | What Moves the Price |
|---|---|---|
| DuraFlex liner repair (sectional) | $850 - $1,400 | Accessibility, height of chimney, whether we need scaffolding |
| DuraFlex flexible liner replacement | $2,800 - $4,500 | Flue length, diameter, insulation requirements, number of appliance connections |
| DuraFlex SW smooth-wall replacement | $3,200 - $5,100 | Corrosion extent, transition collar condition, masonry prep needed |
| Partial chimney rebuild with liner | $4,500 - $7,800 | Courses to rebuild, crown condition, flashing integration |
| Full chimney rebuild with new DuraFlex liner | $8,500 - $14,000 | Height, scaffolding, liner spec, exterior finish matching |
Factors that raise or lower your price: chimney height above roofline (Baltimore’s three-story rowhouses add material and labor), whether the original liner was properly insulated (uninsulated liners fail faster and often reveal masonry damage), and how many appliances tie into the flue. We give you the number upfront - the number on the estimate is the number on the invoice. Call (410) 849-6273 for your free estimate.
Why Baltimore Homeowners Call Hearthstone Chimney Co. for DuraFlex Work
We’ve been answering the phone with a live person for over 42 years, and we’ve learned that Baltimore homeowners - especially those who’ve owned their house long enough to replace a roof and a furnace - don’t want a pitch. They want someone who reads the flue honestly and stands behind the work.
Our 90-Day Done Right Promise isn’t a slogan. It’s in writing. If the DuraFlex liner we installed pulls loose, if the draft doesn’t hold, if anything isn’t right - we come back. No paperwork to dig up, no arguing about whose fault it was. That’s the K.E.Y.S. code: Krafted right, Every time, Your home first, Standing behind it.
Russell Haines and our technicians know DuraFlex products specifically because we’ve pulled, inspected, and replaced them in Baltimore’s actual chimneys - the narrow flues, the offset smoke chambers, the freeze-thaw damage you won’t find in the manual. And when a DuraFlex part isn’t the right answer, we work with HeatShield, Gelco, and other professional-grade brands to solve the problem rather than force a brand match that doesn’t fit.
Photos you can see. A plain-English verdict. A square deal. That’s why they call back.
FAQs
No, independent service by a qualified technician does not automatically void your DuraFlex warranty, though using non-OEM parts for a covered repair can complicate a future claim. As an independent DuraFlex service provider, we document every part we install and will use OEM components when your warranty status requires it - just ask during the estimate.
The camera inspection tells the story. Isolated damage - a cracked tee, a separated collar, a single corroded section - often repairs cleanly. Widesale thinning, multiple cracks, or corrosion along the full length means replacement is the honest call. We’ll show you the footage and explain which category you’re in. Call (410) 849-6273 for a free inspection - estimates are free.
We stock common DuraFlex collars, tees, and flex sections, and our supply chain pulls specialty items within a few business days. Most DuraFlex liner replacements we book in Baltimore are completed in a single visit because we inspect first, order what we need, and arrive prepared.
Eight years is young for a properly installed, properly maintained DuraFlex liner, but we’ve seen it in Baltimore when the original installer skipped insulation, used an undersized liner, or left gaps at the top plate that let water run. The camera inspection shows whether the liner failed or the installation failed - two different problems with two different fixes. We’ll tell you which you have.
The National Fire Protection Association recommends annual inspection for all chimney systems, and DuraFlex liners are no exception. In Baltimore, where we burn hard and weather hard, we agree - especially if you’re burning cordwood in a pre-1950 masonry chimney. An annual Level-2 inspection catches collar fatigue, tee cracks, and crown leaks before they become liner replacements. Call (410) 849-6273 to schedule - estimates are free.
Written by Russell Haines, Owner, Hearthstone Chimney Co. at Hearthstone Chimney Co., serving Baltimore and nearby areas.





Before
After
Before
After
Before
After