Keeping your chimney in top shape helps preserve the chimney’s structural integrity, and regular inspections are critical to identifying and fixing defects and potential problems early. In the end, you prevent creosote build-up and, by extension, potential fires.
Lining your chimney with a chimney liner is an extra step you can take to protect your chimney, the house, and the people inside the property.
Like regular inspections and proper maintenance, adding a chimney liner prevents the build-up of unsafe elements inside the chimney while promoting the efficient release of combustion gases and entry of fresh air for the combustion process.
The rest of this guide is designed to help you learn more about chimney liners, what they do, and the benefits of installing a liner. We’ll also discuss the different chimney liner types, chimney liner installation, maintenance, and general tips.
What is a Chimney Liner?
The chimney exists to help direct combustion gases and excess heat from the fireplace outside the house. The liner is a material that creates a barrier between the flue and the walls of the chimney to protect the chimney.
According to the Chimney Safety Institute of America, the chimney liner is “a clay, ceramic, or metal conduit installed inside a chimney to contain the combustion products and direct them to the outside atmosphere to protect the chimney walls from heat and corrosion.”
What Does a Chimney Liner Do?
The chimney liners serve a range of functions to ensure effective heating while protecting the chimney structure. These functions include;
Protecting the Chimney from Excess Heat
Fireplaces and stoves produce lots of heat. The flue walls will always absorb some of this heat. Where a liner is missing, there’s always the likelihood that the flue and chimney masonry absorbs too much heat. This can compromise the structural integrity of the chimney.
Worse still, remember that some chimneys may be very close to the woodwork in the roof. Excessive heat in an exposed chimney would result in some of the heat transfer to the adjoining woodwork, creating a massive fire risk.
The tests carried out by the US Bureau of Standards found that some unlined chimneys transfer heat so fast that adjacent woodwork can catch fire in under three minutes!
A chimney liner is made from fire-resistant material, thus reduced the transfer of heat to the chimney and, by extension, adjoining woodwork.
Protection from Mordant Byproducts
Masonry chimneys are susceptible to the corrosive effects of combustion. Flue gases are caustic, thus can chomp the mortar joints inside the chimney. Corrosive byproducts found inside the chimney can also cause the inside of the chimney to erode.
Now, consider this happening in an actively used heater. The hot air would only move through the chimney masonry faster, reaching adjoining masonry in record time. It may also cause leakage of carbon dioxide and other harmful combustion gases into the home’s living areas.
Installing a liner protects the flue and chimney from the corrosive, acidic combustion gases to protect home occupants from harmful gases.
Increases Heating Efficiency
Finally, the liner forms an insulation layer inside the chimney that’s critical in preventing heat loss. This insulation layer reduces downdrafts during periods when the chimney isn’t in use. The result is less cold in your home.
Also, downdrafts often mean you need to generate more heat no cancel out the cold air. The greater the amount of cold air entering from the chimney, the greater the amount of heat needed to raise indoor temperatures to the desired setting. By eliminating downdrafts, therefore, chimney liners reducing the cost of heating.
Finally, the liner also prevents heat loss via the chimney walls. In masonry chimneys, especially, a substantial amount of heat is lost via the brick walls and mortar. The liner insulation prevents this form of heat loss.
Benefits of a Chimney Liner
The best chimney liners keep you and your family safe, protect your home, and guarantee a long and efficient chimney life with fewer repairs. The following are four key reasons you should strongly consider lining your chimney;
Protect yourself and your Family
Cracked tiles and missing mortar is a common feature in most masonry chimneys. This can allow noxious smoke and gases to enter your attic and living spaces, creating a massive health risk for you and your family.
Additionally, chimneys create the risk of creosote build-up that increases the risk of fire. The chimney liner is the perfect remedy for these two issues.
Protect your Chimney
The combustion products from the furnace or stove down below can corrode the chimney cause quick and massive deterioration.
From smoke to creosote to smoke and carbon dioxide to water, these elements easily penetrate mortar and brick, which could leave you with a damaged chimney.
Chimney repairs are very expensive, often in the range of several hundred dollars or even a few thousand. The chimney liner protects your chimney from the causative agents.
How to Tell If you Need a Chimney Liner
The easiest way to tell whether you need a chimney liner is to ask yourself if you have one in the first place. If the answer is no, then you need to install a chimney liner.
The following are other signs you need a chimney liner;
Your State Requires so
Yes, some states chimney lining for safety reasons. One such state is Connecticut. The CT state building code interpretation no. I-22-03 of 2003 states that “all masonry chimneys, interior or exterior, be lined.” Another state that demands the chimney lining is Chicago.
Moreover, even in states where chimney lining isn’t mandatory state-wide, some municipalities may demand it. If your state or local municipality requires one, you need to abide by the law.
The Chimney Walls are Deteriorating Fast
The chimney walls eventually deteriorate due to wear and tear. However, the pace of deterioration is typically higher where the liner is missing. That’s because the chimney liner protects the masonry from damaging agents such as moisture and smoke.
A deteriorated chimney exposes you and your family to all kinds of health and safety issues. It also necessitates regular and expensive repairs, such as tuckpointing. Installing a lining can slow down the rate of damage.
There’s Significant Condensation in the Chimney
Finally, you also need to install a chimney lining if you notice significant condensation in the chimney area. Water and moisture are the chimney’s biggest enemies. Seeping water can cause the damper and firebox to rust. It also affects the mortar of the bricks.
Chimney lining prevents water from reaching the chimney walls. It also helps protect the damper and other components of the chimney from moisture damage.
Types of Chimney Liners
There are three main types of chimney liners – clay liners, metal liners, and cast-in-place liners. Here’s what you need to know about each;
Until recently, clay chimney liners were the most common chimney lining solution. The liners are inexpensive as clay tiles are readily available. Clay also performs incredibly well in open fire chimneys as long as there’s proper maintenance.
On the flip side, however, clay liners are also the most labor-intensive of all chimney liner types. Installing the liners can take days. Repair is another difficult process.
Moreover, clay tiles don’t absorb heat fast, neither can they distribute heat fast. This often causes them to crack fast and split apart.
Finally, clay tiles cannot adequately contain liquid combustion byproducts produced by modern gas appliances.
Metal liners have taken the place of clay tiles as the most popular lining type in modern chimneys. They handle gas heaters a lot better and, if properly installed, are durable and very safe. Some even come with a lifetime warranty. Stainless steel and aluminum are the two metals most used in chimney liners.
The only notable downside of metal chimney liners is the cost. Most homeowners pay in the region of $2,500 for stainless steel chimney liners whereas some clay tile liner installations cost under $700.
Finally, cast-in-place is the gold standard for chimney lining. These liners are lightweight cement-like products poured in the chimney passageway along the outer walls, forming a smooth path for flue gases.
The primary advantage of the cast-in-place liner is unmatched strength. These liners are pretty much permanent installations that may not need replacement. They also boost the structural integrity of the chimney.
The only downside here too is cost. If you think stainless steel liners are expensive at around $2,500, cast-in-place liners can cost up to three times more. The cheapest cast-in-place chimney liner installations cost around $4,000.
Can I Install a chimney Liner Myself?
Yes. If you have basic masonry and HVAC skills, you can DIY install your chimney liner and save at least a few hundred dollars in the process. Stainless steel liners are particularly not difficult to install.
All you need to do is buy the right liner, snake it down your chimney, and connect it to the stove. Don’t forget to connect it to the top plate and rain cap at the other end.
That said, though, chimney liner installation is best done by a professional. Any gaps between the liner and stove or top plate can lead to massive air and heat leakage. Also, climbing on the roof and handling the liner while up there is a risky undertaking.
If you trust your DIY skills, though, feel free to give it a try. The other two liner types – clay tiles and cast-in-place are best installed by a licensed professional.
Best Chimney Liner Reviews
1. HY-C ShelterPro NCDB435KIT Aluminum Liner and kit 35-Foot x 4-Inches
This 2-ply 3003 aluminum liner from HY-C Shelter Pro is a tough, durable liner designed to resist corrosion and help expel combustion gases with minimal fuss.
As with all other Shelter Pro line of products, it’s manufactured for appliances with an AFUE value of 83% or lower and U.L. listed for safety.
It features an aluminum collar for slipping the liner through the thimble and comes with an aluminum top plate that measures 16 x 16 inches.
The collar is 2-inch high around the holding diameter. All Shelter Pro appliances are U.L. listed to UL441 and backed by a 15-year warranty.
- Durable aluminum material
- Aluminum cap included
- U.L. listed
- 15-year warranty
- Installation is a two-person job
2. Rockford Chimney Supply RockFlex Model 625S-AC Flexible Chimney Liner (25’x6”)
This second liner from Rockford Chimney is a 0,006 inches thick stainless steel unit with exceptional flexibility and strength.
It’s water and airtight and features seven seams, with 10 corrugations between each seam. When it heats up, it expands to allow even more air out. When it cools down, it contracts.
Inside the kit, you’ll find a vertical appliance connector where the liner fits the female side. Use the quick connect band for this process.
You’ll also find a 13 x 13-inch top plate with a quick connect collar. Feel free to trim it to suit your needs. You can install the unit on your own and save up to $1,200
- Easy DIY chimney liner
- Constructed from 316- stainless steel
- UL 1777 Listed in the USA
- Warranty transferable to next homeowner
- Professional installation recommended
3. Forever Vent SW625SSK SmoothWall Double ply Stainless Chimney Liner (25’x6”)
The model SW625SSK smooth-wall liner from Forever Vent is a double-ply flex-all liner made from a single strip of 316-grade 0.006 stainless steel.
It’s characterized by a corrugated interlocked seam on the outside that provides for maximum strength and flexibility.
Meanwhile, the smooth inner ply walls create positive airflow, increasing drafting by as much as 20% while minimizing creosote buildup. It features unbreakable seam locks that are leak-proof and air and watertight.
This liner is an excellent choice for relining all types of masonry chimneys and can be used with gas, wood pellet, firewood, or oil heaters and stoves. The kit includes a 2-part tee, tee cap, 14 x 14 top plate with a drip collar, a round cap, and fasteners.
- Durable stainless steel construction
- Air and water-tight
- Works with all masonry chimneys
- Lifetime warranty
- Professional installation required
4. WestaFlex Model 9516 Chimney Liner Kit, 25-Feet x 6-Inches
The model 9516 chimney liner from WestaFlex is made from aluminum. Some quick research will tell you that aluminum is one of the best lining materials.
It’s incredibly resistant to the impacts of combustion gases and doesn’t rust. It’s also weather-resistant and can last many years. This particular model is a 25-foot liner that can withstand temperatures up to 500 degrees Fahrenheit.
The kit includes flashing, a rain cap, a B-vent connector, and a mortar sleeve with a maximum length of 45 feet aside from the liner itself. The unit has a bend angle of 36 degrees.
Make sure to pick the right length as you don’t want to come short or see valuable liner go to waste. Depending on your needs, you can choose the 10-foot liner or 25-foot liner. All the two have a 6-inch diameter.
- Durable aluminum construction
- Withstands temperatures up to 500°F
- Kit includes flashing and rain cap
- 36-degree bend angle
- No mention of warranty
5. Fireside FireFlex Flexible Chimney Liner Tee Kit, 15-Foot x 6-Inches
Although many people love aluminum, even more, they prefer stainless steel. This unit from Fireside is constructed from 316Ti stainless steel and used for all fuels. It can also be used for relining or in new constructions.
It’s manufactured using the highest grade certified alloys, with a continuous strip of stainless steel, interlocked and diagonally crimped to ensure 100% gas and water tightness and unmatched strength.
Each FireFlex chimney liner kit includes a Fireside E.Z. connect system comprising a top plate, or flue fit to top plate for chimneys with clay tile liner, E.Z. connects collars, a rain cap, and a 2-part stainless steel tee with a removable snout.
- Durable stainless steel construction
- Kit includes E.Z. connect system.
- Usable for all fuel types
- Lifetime transferable warranty
- Professional installation required
- It’s only 15 foot long
6. Stove Builder International VOLKA-625 6-Inch, 25-Foot Stainless Steel Liner
The VOLKA 625 is designed specifically for wood stoves and is one of the pricier products on this list at about $500. However, it’s also an excellent liner choice that guarantees long-term use with minimal maintenance.
It’s designed for new masonry chimneys, lined or unlined, with at least 4-inch masonry all-round or existing properly built masonry chimneys with cracked clay tile liner.
It’s a 6-inch liner (diameter) made from stainless steel and compatible with Drolet /Osburn wood stoves. The kit also contains a tee cap, tee body, liner cap, tee take-off leg, and chimney liner support plate. It’s backed by a lifetime warranty.
- Stainless steel build
- All installation components included
- Works with new or existing chimneys
- Lifetime warranty
- It’s a bit pricey
7. Fireside Chimney Supply FireFlex Insulation Wrap for ½-3-6-Inch, 25-Foot Liners
It’s strongly recommended that you insulate your stainless steel chimney liner to minimize creosote buildup.
When you install the right liner insulation, your reline job provides zero clearance and achieves a 1777 UL rating. This is a chimney liner insulation blanket kit for liners ranging from 3-14 inches.
Included inside the insulation kit are a ½-inch premier wrap chimney flue liner insulation blanket with protective foil-faced insulation wrap, a 16oz can of adhesive 25/30/35-inch roll of retractable mesh, 150-foot foil tape, and two S.S. clamps to sure the insulation from top to bottom.
- A 150-foot roll of foil tape
- Adhesive included
- Installation clamps included
- Ideal for 3-14 –inch liners
- Requires professional installation
8. Rockford Chimney Supply Chimney Liner Insulation Blanket Kit, 3-6-Inch by 25 Feet
Finally, this Rockford is another chimney liner insulation blanket. It’s a ½-inch insulation blanket that helps homeowners meet 1777 UL listing standards in the U.S. It also provides zero clearance to combustibles.
However, it’s slightly limited compared to the above liner blanket as it’s only designed for liners up to 6.0 inches in diameter. Using the liner blanket adds about 1.5 inches to the overall diameter of the liner.
Remember that Rockford chimney liner blanket kits include everything you need for the installation. These are a ½-inch x 24-inch x 25-foot foil face insulation wrap, stainless steel retractable mesh, 3M insulation spray adhesive, and a good HVAC foil tape roll. Two clamps for holding the mesh in place are also supplied.
- Stainless steel retractable mesh included
- Insulation spray adhesive included
- Installation clamps included
- HVAC foil tape included
- Requires professional installation
Indeed, the National Fire Protection Association (NFPA) recommends that masonry chimneys that burn solid fuels are inspected at least once a year by a licensed professional.
The chimney liner is an invaluable component of the chimney system. Without the lining, the chimney is exposed to attack from combustion gases, which can accelerate chimney deterioration.
An unlined chimney also serves as a pathway for downdraft, often resulting in heating inefficiency. If you haven’t installed one, speak to your HVAC contractor about it to discuss your options.