How To Reline a Chimney Flue

* Cost data in this article sourced from contractor estimates used by Angi.

Over time, the flue lining in your chimney can deteriorate, turning your cozy fireplace or wood stove into a serious safety hazard. When this happens, relining the chimney flue is crucial to prevent gas leaks, house fires, and structural damage. While this task is best left to professionals, it’s still helpful to understand the process. In this guide, we’ve rounded up everything homeowners should know about how to reline a chimney flue.

Understanding Chimney Flue Liners

Chimney flue liners play a crucial role in protecting your home from the heat and byproducts of combustion. They serve three main purposes:

• Contain combustion gases and direct them outside
• Protect the chimney walls from heat and corrosion
• Improve the efficiency of your heating appliance

Over time, these liners can deteriorate due to factors such as age, weather exposure, and the corrosive nature of flue gases. When this happens, relining becomes necessary to maintain the safety and efficiency of your chimney system.

Preparing for Chimney Flue Relining

Rellining your chimney flue starts with a thorough chimney inspection to identify any structural issues or damage that need to be addressed before installation. Professional chimney sweeps can perform this inspection and provide recommendations for repairs or cleaning.

Types of Chimney Flue Liners

Once any structural problems have been addressed any structural problems, you’ll need to choose a chimney flue liner. There are several types of chimney flue liners available, each with its own advantages:

• Cast-in-place liners: Pouring a cement-like product into the chimney creates a seamless, insulated cast-in-place flue.
• Clay tile liners: Though durable and cost-effective, clay tile liners can be difficult to install in existing chimneys.
• Stainless steel liners: These versatile liners are both durable and easy to install.

For this project, Mark Schaub used a stainless steel liner, which is an excellent choice for retrofitting an existing chimney.

Chimney Flue Insulation

Proper insulation will improve the performance and longevity of your chimney liner. In the video, Schaub used ceramic wool insulation wrapped with foil and protected by armor mesh. This insulation serves several purposes:

• Improves draft and reduces creosote buildup
• Protects the liner from thermal shock
• Increases the overall efficiency of the heating appliance

To install this type of insulation, wrap the ceramic wool insulation around the stainless steel liner. Cover the insulation with foil to create a moisture barrier, then wrap the foil-covered insulation with armor mesh to protect it during installation.

Materials and Tools Needed to Reline a Chimney Flue

To reline a chimney flue, you’ll need the following materials and tools:

• Armor mesh
• Ceramic wool insulation
• Chimney cap
• Heat-resistant masonry adhesive
• Rope and weight
• Safety equipment (gloves, goggles, dust mask)
• Screwdriver
• Silicone sealant
• Stainless steel chimney liner (sized appropriately for your chimney)
• Tin snips

Steps To Reline a Chimney Flue

Relining a chimney flue is a complex process that requires careful attention to detail, which is why we recommend hiring a professional. Here’s a step-by-step guide:

1. Prepare chimney top: Apply heat-resistant masonry adhesive to the top edge of the fireplace flue.
2. Install steel cap: Set the stainless steel cap into the wet adhesive at the top of the fireplace flue.
3. Extend flue (if necessary): Attach a 12 to 16-inch-tall section of clay flue tile with heat-resistant masonry adhesive to extend the flue, as Schaub did with the water heater flue in the video.
4. Feed liner through flue: Drop a weighted rope down the water heater flue to an assistant inside the house. From the roof, tie the rope end to the stainless steel chimney liner and feed it down the flue. Have the assistant pull the rope, guiding the chimney liner down the flue and into the house.
5. Secure flashing: Seal the chimney liner flashing to the flue extension with silicone sealant.
6. Connect flue to heating appliance: Inside the house, trim the end of the chimney liner and connect it to the vent pipe (for gas appliances), connector pipe (for wood stoves), or smoke chamber (for fireplaces). Secure the liner with clamps and sealant as needed.

Schaub emphasizes the importance of proper sealing and insulation to ensure the liner functions effectively and safely.

Safety Considerations When Relining a Chimney Flue

Relining a chimney flue is a job that requires expertise and attention to safety. Here are some important safety considerations:

• Work with a professional: Chimney relining is not a do-it-yourself (DIY) project. It requires specialized knowledge and skills to ensure proper installation and safety.
• Use appropriate safety gear: When working on the roof or handling materials, use proper safety equipment such as harnesses, gloves, and eye protection.
• Ensure proper ventilation: During the installation process, make sure the area is well-ventilated to prevent the buildup of any fumes from adhesives or sealants.
• Follow local codes: Be aware of and comply with local building codes and regulations regarding chimney liners and venting systems.

Maintenance After Relining a Chimney Flue

After relining your chimney flue, proper maintenance is crucial to ensure its longevity and continued safe operation. Here’s what to do:

• Schedule regular inspections. Have your chimney and liner inspected annually by a certified chimney sweep.
• Keep the chimney cap clean. Regularly check and clean the chimney cap to prevent debris buildup.
• Monitor for signs of damage. Watch for signs of deterioration or damage, such as rust on the liner or water stains on the chimney.
• Clean the chimney regularly. Depending on use, have your chimney cleaned at least once a year to prevent creosote buildup.

Cost Considerations for Relining a Chimney Flue

The cost of relining a chimney can vary depending on several factors, including your chimney size, the liner type used, your roof’s height and pitch, and your location. For a stainless steel liner, you can expect to pay around $65 per square foot for the liner itself, plus $400–$1,250 for professional installation.

Clay and cast-in-place liners are less expensive at $10 and $25 per square foot, respectively. However, they require more labor and specialized equipment to install, driving up the total project cost.

Don’t forget to account for the cost of a professional chimney inspection, which costs an average of $250. You may also need a building permit. If your chimney needs to be cleaned or repaired, that will add to the cost.

Our Conclusion

Relining a chimney flue is not a cheap or DIY-friendly project, but the benefits of a properly lined chimney far outweigh the costs. With professional installation and regular maintenance, you can enjoy a safe and efficient chimney for years to come.