Liner Sized to Your Appliance Before Any Material Is Ordered
Wrong diameter produces condensation. Right sizing produces reliable draft.
We Order Any Liner
Liner Sized to Your Appliance Before Any Material Is Ordered
The liner is sized before it is ordered. An oversized liner causes condensation. An undersized liner causes backdrafting. Neither is acceptable.
A chimney relining replaces a failed or inadequate flue liner with a new one matched to the connected appliance. The liner is the interior channel running the height of your chimney. It contains combustion gases, protects surrounding masonry from heat, and establishes the correct flue diameter for your appliance to draft efficiently.
Relining is not the same as installing a new liner in a new fireplace. It is a replacement, removing or bypassing the existing liner and installing a new one that meets current conditions. Those conditions include the fuel type the appliance burns, the BTU output it produces, and the vertical height of the flue. At Novak Chimney Masters, every relining project starts with those three numbers. The liner is sized before it is ordered. That sequence matters because an oversized liner causes condensation. An undersized liner causes backdrafting. Neither is acceptable.
What most homeowners don't realize about chimney relining: the liner that came with the house was sized for the original appliance. If that appliance changed, and in most Houston homes built before 1990, it did, the liner was not changed with it.
Houston's Short Fire Seasons Crack Clay Tile Liners Faster Than Most Climates
Houston's clay tile liner failures follow a pattern specific to this climate and housing stock. Most homes built between 1950 and 1985 in this market have clay tile flue liners. Those liners were installed for wood-burning fireplaces. They are fired ceramic sections joined with refractory mortar, designed for exactly that use.
Decades ago, most of those homes converted to natural gas heat. The furnace, the water heater, and sometimes the fireplace itself switched fuels. The liner stayed. Natural gas combustion produces acidic condensate, water vapor and carbon dioxide that cool inside the flue and form weak carbonic acid on contact with the tile surface. Clay tile was not designed for that chemistry. The acid eats the mortar joints between sections first. Then the tile faces begin to fracture from the inside out.
In Houston, cold-start firing, lighting a fireplace that has been cold for eight or nine months, creates rapid thermal expansion in rigid clay tile. That expansion is more severe than what liners in continuously heated climates experience. The result: joint separation and hairline fractures invisible from the firebox but visible on camera during a Level 2 inspection.
Richmond, Rosenberg, and the broader Fort Bend County corridor contain significant mid-century housing stock where this pattern is among the most common findings our crews document. We reach those communities regularly from our North Post Oak Road dispatch.
What We Found During a Liner Assessment in Missouri City
I've been doing liner assessments long enough to know that the hardest conversation is the one where the homeowner looks at a clay tile liner on camera and asks why it looks fine from below but has four separated joints in the upper third.
We ran a camera through a flue in Missouri City last fall, a 1971 house, original clay tile liner, gas furnace connected through a combination flue. The homeowner had called because the furnace was producing a faint sulfur smell during heating cycles. Nothing dramatic. Just wrong.
The camera showed what the firebox couldn't. Three mortar joints in the upper flue section had fully separated. One tile had a through-crack running its full width. Hot combustion gases and trace carbon monoxide were bypassing the liner at those points and contacting the surrounding masonry, specifically, the framing at the attic level where the chimney passed through the ceiling.
We recommended a full stainless steel flex liner installation sized to the furnace's BTU output and the flue's vertical height. The homeowner had been using that system for at least two heating seasons with a liner in that condition. The smell was the first symptom.
The repair scope was a flex liner from the appliance connection to the termination cap. Clean installation, correct diameter, insulated. The smell stopped after the first heating cycle.
That story matters because the homeowner had no reason to suspect the liner. The furnace was running. The house was heating. The only signal was a smell that was easy to dismiss as seasonal. A Level 2 camera inspection found what a Level 1 visual inspection cannot.
What Happens When the Liner Diameter Is Wrong
Getting the liner diameter right is the technical requirement that determines whether the system works. This is the most common question we get after presenting a relining scope: why does the diameter matter so much?
A liner that is too wide for the appliance cannot maintain flue gas temperature above the condensation point. The gases cool before they exit. Condensate forms on the liner walls. That condensate is acidic for a gas appliance. It begins deteriorating the new liner immediately.
A liner that is too narrow restricts the volume of gas the appliance can push through the flue. Draft suffers. The appliance struggles to exhaust completely. In a worst case, combustion gases back up into the living space.
We calculate liner diameter from the appliance's BTU output and the flue's effective vertical height, two measurements specific to your system, not estimated from average figures. The liner is ordered after that calculation. Not before.
Our Standards for Chimney Relining in Houston
Our liner installations follow a defined standard:
Liner type selected by application
Stainless steel flex liner for most residential relining projects, it navigates minor flue offsets common in older Houston masonry without requiring a straight path. Rigid stainless for straight, tall flues where flex would reduce effective diameter through compression. Cast-in-place for severely deteriorated or irregularly shaped flues where neither flex nor rigid seats correctly.
Insulation included on all gas appliance liner installations
Liner insulation maintains flue gas temperature above the condensation point. In Houston's mild-climate chimneys, where firing temperatures are lower than in colder markets, uninsulated liners are more susceptible to condensate formation during normal operation.
Sizing calculated before ordering
BTU output and vertical flue height confirmed before any liner is specified. No estimating from visual inspection alone.
Termination cap matched to liner diameter and fuel type
The cap at the crown must be compatible with the liner system. An oversized cap opening allows weather and debris entry. An undersized one restricts flow at the termination point.
Post-installation inspection before appliance connection
The liner is inspected from top to bottom after installation and before the appliance is connected to the flue.
The Relining Process at Novak Chimney Masters
Diagnostics
Every relining project begins with a Level 2 camera inspection if one has not already been completed. The camera confirms which liner sections have failed, identifies any mortar joint separations, and documents the full condition of the flue from appliance connection to termination. The inspection also measures the flue's effective height and interior dimensions. Those measurements are the inputs for the sizing calculation.
We also review the connected appliance, fuel type, BTU output, and venting configuration. For gas appliances, we confirm whether the existing venting connection is compatible with the new liner system or whether the connection point needs to be modified.
Installation
The liner is installed in a single operation. For a stainless steel flex liner, the liner is assembled at the top of the chimney and lowered into position. Insulation is wrapped or poured around the liner as it seats. The bottom of the liner is connected to the appliance flue collar. The top is terminated at the crown with the matched cap.
For a cast-in-place liner, an inflatable form is positioned in the flue and the refractory mortar mix is poured or pumped into the space between the form and the existing flue walls. The form is removed after cure, leaving a seamless, smooth interior surface.
Post-Service Testing
After installation, the liner is inspected by camera from termination to appliance connection. We confirm the liner is seated correctly, the insulation is continuous, and the termination cap is secured. The appliance is not connected until the inspection is complete. The homeowner receives a written record of the liner type, diameter, installation date, and post-installation findings.
Chimney Relining Across Greater Houston
Novak Chimney Masters serves chimney relining appointments across Greater Houston. We regularly schedule liner assessments and installations in the communities below. Call (832) 701-0196 to confirm availability in your area.
The Conversation Starts With a Sizing Calculation, Not a Product Selection
If a Level 2 inspection identified liner damage, or if your appliance has changed since the chimney was built, the relining conversation starts with a sizing calculation, not a product selection. Contact Novak Chimney Masters at (832) 701-0196 or email in**@*****************rs.com to schedule your liner assessment. We serve the full Greater Houston Area from our North Post Oak Road dispatch.
- ✕ Separated mortar joints
- ✕ Cracked clay tile faces
- ✕ Acidic condensate damage
- ✕ Wrong diameter for appliance
- ✓ Sized to BTU and flue height
- ✓ Insulated stainless liner
- ✓ Matched termination cap
- ✓ Camera-verified installation
Wrong diameter produces condensation. Right sizing produces reliable draft. Every reline starts with the numbers.
Customer review coming soon.
Frequently Asked Questions
◆ How do I know if my chimney needs relining?
A Level 2 camera inspection is the reliable way to confirm liner condition. Separated mortar joints, cracked clay tile, or a change in the connected appliance since the chimney was built are all common reasons a reline is recommended. Faint odors during heating cycles can also be an early symptom.
◆ Which liner type is right for my chimney?
Stainless steel flex works for most residential relining projects and handles minor flue offsets in older Houston masonry. Rigid stainless suits straight, tall flues. Cast-in-place is used for severely deteriorated or irregularly shaped flues. We select the type after inspecting your flue.
◆ Why does liner diameter matter so much?
A liner too wide cannot hold flue gas temperature above the condensation point, causing acidic condensate. A liner too narrow restricts draft and can push combustion gases back into the living space. We calculate diameter from your appliance's BTU output and the flue's vertical height before ordering.
◆ Do gas appliance liners need insulation?
Yes. We include insulation on all gas appliance liner installations. It maintains flue gas temperature above the condensation point. In Houston's mild-climate chimneys, where firing temperatures run lower, uninsulated liners are more susceptible to condensate formation.
◆ Do you inspect the liner after installation?
We inspect the liner by camera from termination to appliance connection after installation. We confirm correct seating, continuous insulation, and a secured termination cap. The appliance is not connected until the inspection is complete, and you receive a written record of the work.
Ready to Get Started?
Contact our team today for a free consultation. Don't run an appliance through a damaged liner.
© 2026 Novak Chimney Masters • in**@*****************rs.com • Serving Greater Houston, TX
What this work is measured against
- NFPA 211Standard for Chimneys, Fireplaces, Vents and Solid Fuel-Burning Appliances.
- UL SolutionsListing standards for chimney liners, factory-built chimneys and venting components.
- Chimney Safety Institute of AmericaCertification body for chimney sweeps and the source of the homeowner guidance we work to.
- CPSC Carbon Monoxide Information CenterFederal hub for CO hazards, alarms and appliance maintenance.
- National Fireplace InstituteCertification standard for technicians working on fireplaces, gas systems and venting.
Schedule Liner Sized to Your Appliance Before Any Material Is Ordered in Houston
Every visit starts with a written scope confirmation before the work is booked. Serving Greater Houston from a single dispatch point on N Post Oak Rd.