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.
HeatShield Flue Liner Replacement: The Allentown Owner’s Guide
We stock and install HeatShield-compatible flue liner replacement in Allentown, with most jobs running $1,800-$3,400 installed depending on liner diameter, height, and whether the existing clay flue tiles need extraction. Our trucks carry common HeatShield cerfractory flue liner diameters from 5.5″ to 8.5″ for same-day replacement on standard residential chimneys up to 25 feet. Most Allentown owners discover the problem after a Level-2 inspection turns up spalling tile, glazed creosote behind a cracked liner, or smoke leaking into wall cavities through a compromised flue in homes built before 1980.
Which HeatShield Models This Applies To
HeatShield manufactures two distinct product lines that get called “flue liner replacement” in conversation, and mixing them up leads to mismatched parts and second trips.
The HeatShield Cerfractory Flue Liner is a standalone, cast-in-place replacement system. It arrives as a dry mix that our technicians spray-coat onto a custom form inserted in your chimney. Finished interior diameters run 5.5″, 6.5″, 7.5″, and 8.5″ - critical because an oversized form leaves too thin a wall, and an undersized form chokes draft in Allentown’s older masonry chimneys, many of which were built to 8×8 or 8×12 exterior clay dimensions. The model designation is stamped on the original installation tag, usually found on the smoke shelf or inside the damper frame. No tag? We measure the existing flue at three points - top, middle, and below the smoke chamber - because clay tiles often taper or swell from decades of heat cycling.
The HeatShield Resurfacing System is a repair coating, not a structural liner. It fills gaps and smooths pitted clay but cannot replace a fully collapsed or missing flue liner. We’ve seen Allentown homeowners order the wrong system after confusing these names on parts sites. We clarify before anything ships.
Hearthstone Chimney Co. is an independent service provider, not affiliated with HeatShield. We source through authorized distribution and also stock DuraFlex and Gelco stainless liners for situations where a cast-in-place cerfractory liner isn’t the right fix.
Signs Your HeatShield Flue Liner Replacement Is Failing
- White efflorescence or spalling brick on the chimney exterior. This means moisture is migrating through cracked mortar joints in the flue liner, freezing in Allentown’s January-February cold snaps, and pushing brick faces off from the inside out. The liner has lost its watertight seal.
- Bits of clay tile in the firebox or cleanout door. These shards indicate the original clay flue liner is disintegrating, often from thermal shock when a chimney fire occurred years ago and went unnoticed. The HeatShield liner beneath may be compromised if it was installed over unstable substrate.
- Smoke odor in upstairs rooms during heavy rain. A cracked cerfractory liner or failed crown seal lets water follow the flue path, saturating surrounding masonry. Allentown’s spring storms and freeze-thaw cycles accelerate this.
- Draft problems that worsen on humid summer days. A liner with internal scaling or delamination creates turbulence instead of smooth draw. We’ve traced this to HeatShield liners installed in the early 2000s that weren’t fully cured before first firing.
- Your home inspector flagged “recommend Level-2 evaluation” at sale. This is the most common discovery path. The visible flue from the roof or firebox shows enough distress that a camera inspection is warranted before closing.
Replacement Cost & What’s Included
HeatShield cerfractory flue liner replacement in Allentown typically breaks down as follows:
| Component | Price Range |
|---|---|
| HeatShield cerfractory material (per flue) | $680-$1,100 |
| Custom form rental/fabrication | $240-$380 |
| Labor: extraction, prep, spray application, cure | $740-$1,600 |
| Level-2 camera inspection with photo report | $180-$260 |
| Typical total installed | $1,800-$3,400 |
Taller chimneys, multiple flues, or extraction of collapsed clay tile add labor hours. We price this upfront, not after we’re inside. The 90-Day Done Right Promise covers the installation in writing - if it’s not right, we come back, no arguing. HeatShield’s material warranty runs 20 years; our workmanship backs the first 90 days with the same certainty.
Current standing offers: $50 off any repair over $250, free second opinion on any written estimate, and a permanent 5% senior and veteran discount.
DIY or Call Us?
Here’s where we’re direct. A homeowner can safely check the damper operation, shine a flashlight up the flue for visible tile damage, and note any debris in the cleanout. What you cannot safely do: extract fractured clay tile from a confined flue, operate the pneumatic spray equipment that applies HeatShield material at proper density, or verify cure integrity without a borescope camera.
The cerfractory mix must reach 1,900°F service temperature tolerance through precise thickness - too thin and it spalls, too thick and it chokes draft. We’ve been called to redo DIY-adjacent jobs where the form was mis-sized or the cure was rushed before Allentown’s damp weather allowed proper drying. The chimney doesn’t care what it looks like from the street. We check what’s inside.
Call (610) 632-1394. A live person answers, even at 10 PM on a Sunday.
FAQs
A properly installed HeatShield cerfractory liner lasts 20 years or more, per the manufacturer’s warranty. Allentown’s freeze-thaw cycles and occasional chimney fires from green firewood are the main accelerators of wear, which is why we recommend annual inspection after year five. Call (610) 632-1394 to schedule - estimates are free.
Surface cracking under 1/8 inch can sometimes be addressed with HeatShield’s resurfacing system if the underlying structure is sound. Anything deeper, or cracking that follows the mortar joints of original clay tile beneath, requires full replacement - resurfacing over unstable substrate fails within two seasons. We document this with camera footage you can see before you decide.
Most single-flue HeatShield replacements in Allentown are completed in one day, with a 24-hour cure period before the first fire. Multi-flue chimneys or those requiring clay tile extraction may extend to a second day. Our technicians arrive background-checked and uniformed, and we confirm the schedule the morning of - we’ll be there when we say.
We stock common HeatShield cerfractory diameters and maintain forms for 5.5″ through 8.5″ liners on our Allentown service vehicles. Uncommon sizes or multi-flue configurations may require a 24-hour parts pull from distribution. We’ll know after the initial inspection and tell you before anything is ordered.
Written by Russell Haines, Owner, Hearthstone Chimney Co. at Hearthstone Chimney Co., serving Allentown and nearby areas.





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