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Friday, January 8, 2021

What is a Flue Liner and Why do You Need One?

Flue liners are an important part of any furnace, water heater, boiler, or fireplace system. Liners have been required by code since 1927, but have been in use since the 1870’s. In a nutshell, the purpose of a flue liner is to keep toxic flue gasses such as Carbon Monoxide, other aldehydes, and tar vapors inside the flue and allow them to exit the house. It was found early on that with masonry chimneys, the mortar joints tend to deteriorate over time and develop cracks and gaps that allow gasses to leak through them. So, liners were invented. Vitreous clay tile flue liners were created to line the interior chimney so that flue gasses could not escape the flue. This is extremely important for the health and safety of the occupants of a home.

However, over time, rainwater, moisture, and acidic flue gasses eat away at mortar joints between the liner sections. Clay tile flue liners are made in two-foot sections and installed ahead of the exterior masonry chase. They have a bed of mortar between each section. When these mortar joints erode, they create gaps between the liner sections – and we are back to square one with toxic gasses leaking into the house. 

A liner has been removed and one remains

When rehabbing a house, a contractor may find that there is no liner installed in a masonry chimney. This is more common in older homes with utility flues serving heating appliances and water heaters, but occasionally is found with fireplaces as well. It is extremely common, however, to find a flue liner with missing mortar joints. This can be remedied in most cases with a method using a ceramic joint filler, which is applied using a heavy-duty vibrating bell sponge while pouring the mix from above the flue liner. It involves special equipment and trained professionals to do the job. In cases with large gaps between liners this method cannot be used, and relining is necessary.

A second common issue with flue liners is incorrect sizing. If a liner is not correctly sized to the appliance, smoking or backup of toxic gasses can result. This often occurs when a high efficiency furnace is installed, leaving a water heater to vent on its own, which it cannot do in an oversized flue. A liner for the water heater will be necessary unless a replacement water heater that vents out the side is used instead. An incorrectly sized flue liner serving a fireplace will cause backup of smoke and toxic gasses into the home.

Stainless steel liner with a single flue tile on top
The third common issue with clay tile flue liners is damage from a chimney fire. As fireplace inspectors we see this on a daily basis, and in most instances, the homeowner had no idea that they had a chimney fire unless they caught it at the time, or a neighbor knocked on their door after they saw flames shooting out of the chimney. Most chimney fires are of short duration because as flammable creosote burns it expands to ten times its size and snuffs out the fire. But even a short duration chimney fire can cause a lot of damage to flue liners, usually leaving vertical and sometimes horizontal breaks behind. These breaks open to as much as ¾” when the appliance is used, once again allowing gasses to escape. The only solution is to reline the flue. Fortunately, homeowner’s insurance covers chimney fire damage since it is considered a “hostile” fire. If a home was purchased within 12 months prior to finding the damage the new owner may have recourse with the seller, who can file a claim on their insurance. Chimney repair can be expensive, and the last thing a new homeowner wants is a huge un-budgeted-for expense after a home is purchased. This is why an inspection of all flues in a home is so important prior to purchase. 99% of Home inspectors do not inspect chimneys, only a chimney sweep with the proper equipment can, and should, do a chimney inspection using a chimney camera system. If timing does not allow for an inspection, figure in extra cost in your rehab estimate based on the size of the chimney.

Clay tile flue liners being installed as masonry is built up
Relining involves removal of the cement cap and extraction of the clay tile flue liner, installation of a replacement stainless steel liner with insulation, and rebuilding the cement cap. Other demolition such as removal of a damper casing, firebrick, or a wall may be necessary. Smoke chambers are often in poor condition and need to be parge coated with insulating mortar.  It is important to use a liner with the same I.D. dimensions as the previous liner, or in some cases, larger, and the only way to do that is to take the old liner out first. In rare cases, the flue is oversized so installation of a new liner may be possible without extracting the old liner.

Codes must be followed with flue liners – Chapters 10 and 18 in the International Residential Code cover most of this information, and the National Fire Protection 211 Standard for Chimneys, Fireplaces, Vents, and Solid Fuel Appliances also applies since it is the industry standard. We also follow the NFPA 54 National Fuel Gas Code.

A stainless steel flue liner being prepped   

A professional chimney contractor should do this type of work since they are familiar with the codes and standards and have the equipment and expertise to do the job. In the greater Kansas City area and other jurisdictions across the U.S., a Class DM Master Mechanical (HVAC) Contractor License is needed in order to reline flues, and a permit is required for the work, with an inspection by the building codes inspector.


The cost to reline a flue can very greatly and is determined by the type, size, and length of liner needed and difficulty level of the job.


Marge Padgitt is a 35-year chimney industry veteran. She trains professional chimney technicians across the U.S. and is the author of The Chimney and Hearth Pro’s Resource Book, and Wood-Fired Heating and Cooking, along with many training DVDS and presentations. Contact her at, 816-461-3665, or

Monday, October 5, 2020

Chopping Therapy

By Audrey Elder


That’s right, chopping therapy. Me, a nice warm red and black flannel, my
hiking boots, my axe and wedge. Out to the woodpile I go, find a nice wide chunk of walnut, lift the axe up over my right shoulder…. and whack! I remember why I brought the wedge. Either way, after a full wheelbarrow load of fresh split logs for the fire… I feel better.

Full disclosure here, I own a gas-powered log splitter. That’s not the point. There are just those moments in life that require a break from everything, a little exercise induced endorphins and a zoned in focus on a simple task. For me, there is no better way to achieve this than chopping firewood.

 Imagine this scenario. It’s a beautiful chilly Saturday in October. A crisp cool north wind pours across the yard carrying hundreds of gold and red leaves from summers fading trees with each gust. Inside, a full house filled with the sounds of individual activity. Kerplunk, boink, swoosh, boink, ahh someone is playing a game on their tablet. Someone else is having a lively conversation on their phone. Another is cranking up the volume on the television, this is their favorite part of the movie! You clutch the book in your hand, your eyes roll slightly, the plot has just begun to reveal itself. You count to ten. The words blur as if they refuse to be legible amongst ALL THE NOISE. See? This, this my friends, is when the woodpile calls to save your sanity.  

 It could be a needed break from a frustrating event like trying to put a dresser together that came in a flat box. It could be when your computer decides to update everything the moment you’re about to send the email that was due an hour ago.  Or, in 2020, it could just be because it’s 2020. Whatever it is that brings you to the brink of allowing your inner five-year-old who didn’t get a puppy to show up around any other human, nothing works better than chopping therapy. Not to mention the added bonus of never having to leave your home, spending NOTHING, and actually getting something accomplished.

 The first log that splits all the way through creates an inner celebration. A joy of nearly primal accomplishment. There I stand above my TWO pieces of firewood holding my axe to the sky, steam pouring from each breath into the frigid air as I think about how this act may please my flannel wearing ancestors who chopped wood or froze. Depending on what level of angst brought me to this place, I may keep chopping! I might look down at those two pieces of firewood and think, those are a bit large. I might decide to split each of them as well. I of course negate the wedge with at least the first whack. Even this will provide a place to pound the wedge in. The first piece splits! Ah Yes! I am still dominating this wood pile! The second piece….whack…wedge….whack….wedge stuck…whack….wedge stuck further….wood turned sideways….attempt to push wedge out with axe…axe is stuck….lift axe with log attached and beat log on another log… At this point, whatever has brought me to this place is gone and forgotten. It’s just me and the impossible piece of wood. It’s war and I’m determined to win. So, whether I actually do win and leave pushing my wheelbarrow full of firewood pridefully to the front porch or I end up having the emotional outbreak I likely needed to in the first place, its over. I’m ready to return to the task inside that awaits me. Refreshed, clear headed and completely physically exhausted.*

 These kinds of days end the same way all days do, the sun goes down. We all gather in the living room after dinner to watch a show, cozy and warm as the fire flickers through the glass door of the woodstove. My husband lovingly reaches over and taps my shoulder, “You look like you feel much better now.” I smile with tranquility, “I do feel better dear, much better.”

Chop safely, chop often, and always chop for inner peace. In some odd way, I’m sure this helps make the world a better place.


*For the same results in the summertime, spend half an hour trying to start a gas-powered lawnmower.

Audrey Elder is a free-lance writer and owner of Past to Present Research in Independence, Missouri. She lives on a 14-acre homestead with her husband and a few million honeybees.


Saturday, September 26, 2020

The CSIA Shares Fire Safety Tips In Honor Of National Chimney Safety Week


PLAINFIELD, Ind., Sept. 24, 2020 /PRNewswire/ -- Each year, the Chimney Safety Institute of America (CSIA) and thousands of industry professionals spend the last week in September sharing chimney safety tips and educating homeowners on how to best maintain and use their chimneys and fireplaces.

Designated National Chimney Safety Week by the CSIA back in 1978, this annual observance serves as a reminder to homeowners to take fire safety into their own hands and to schedule annual maintenance services prior to using their fireplaces each year.

According to the latest numbers from the U.S. Consumer Product Safety Commission, an average of 22,300 U.S. residential structure fires were caused by chimneys, fireplaces, or chimney connectors between 2012-2014, resulting in an average of 60 injuries, 20 deaths, and $116.4 million in property loss each year.

The mission of the CSIA and the goal of National Chimney Safety Week is to lower these numbers dramatically by training industry professionals and educating homeowners on the importance of proper chimney maintenance.

Annual maintenance should include:

  • A yearly chimney inspection by a CSIA-certified chimney technician
  • A yearly chimney cleaning, if needed

It only takes a matter of minutes for a chimney fire to spread to other areas of the home, but a few minutes of proactive care can reduce that risk, so homeowners can safely enjoy their fireplaces this fall and winter.

Chuck Roydhouse, President of CSIA shares,

"It's not just wood-burning chimneys that can be hazardous. Gas fireplaces, gas or oil heating furnaces and water heaters, and other fuel-burning appliances can create unsafe chimneys, too. External factors other than fire source can cause dangerous situations, including: weather, animals residing in the flue, aging structure, and foreign obstructions. So, inspect chimneys every year."

To find a CSIA-certified sweep in your area, head to

About CSIA
The Chimney Safety Institute of America (CSIA) is a nonprofit organization governed by a volunteer board of directors dedicated to the education, training, and certification of chimney and industry related professionals. Additionally, we strive to advance public awareness about the dangers of chimney fires and other problems related to the maintenance and performance of chimney and venting systems.

CSIA is the only non-profit national training academy for chimney technicians, and the CSIA-Certified Chimney Sweep® credential is acknowledged by industry organizations, insurance underwriters, local, state, and federal agencies as the measure of a chimney and venting technician's knowledge about the evaluation and maintenance of chimney and venting systems. CSIA is the standard of excellence in the chimney and venting industry.


Saturday, September 19, 2020

Don't Fire Up that Fireplace Too Soon!

Just because the calendar says it is Fall, doesn't mean that homeowners should light up their wood stove or fireplace. Each year, many people light a fire without considering the consequences of doing so.

And this year due to the pandemic many people are staying at home and look for some form of entertainment. A nice crackling fire would set the mood just right - but don't do so until a few things have been addressed. 

- Did you open the damper?  This is the first thing people forget to do when lighting a fire. The house will fill up with smoke quickly. Open the damper fully before starting a fire in a fireplace, and if you forget, open it and do NOT turn on the attic fan or the problem will get much worse. Open a door instead.

- Did you have the chimney inspected and swept after the last wood burning season?  If not, don't start a fire yet. Call a professional chimney sweep to service the chimney first. And next year, do this in the spring. 

- Do you have a cover on the flue to keep birds and animals out?  If not, birds and squirrels may have built flammable nests in the chimney. A chimney sweeping will usually take care of it, then have a proper stainless steel cover installed. Don't buy a cheap cover that will rust - get stainless steel.

- Are you prepared with dry seasoned cordwood?  This should be purchased or cut and split at least six months in advance of the season so it is properly dried out to 20% or less moisture content. Buy a moisture meter online or from your chimney sweep. Wet wood takes longer to burn and creates more creosote and Carbon Monoxide so don't use it. 

- Do you have the right type of wood? Use almost any type of hardwood (Oak is a favorite) or softwood, but don't ever use soft pine which burns too hot and too fast and is a fire hazard. Also, keep the use of Hedge down to one piece of wood to two pieces of another type. Hedge also sparks and burns very hot and can be a chimney fire hazard.   

 - Don't start a fire unless it is 40 degrees F or less. Yes, you read that correctly. There needs to be enough of a temperature differential between the outdoors and indoors for the chimney to function correctly and draft smoke and flue gasses out of the house. If you simply must have a fire in warmer weather put some candles in the fireplace. 

- Warm the flue up with a very tiny fire before lighting a big fire. This gets draft going. For wood-burning stoves and inserts a Draw Collar can prevent smoking backup at start up and cool down. Ask your chimney sweep about this product. 

- Constant annoying smoking or smoke smell? This could be a sign that the house is under negative pressure, which is extremely common. There are several possible solutions based on your particular house layout. This should be discussed with a professional chimney sweep or venting specialist. One solution which often works well is a Whole House Ventilator. 


Marge Padgitt is the owner and President of HearthMasters, Inc. in Kansas City, Missouri. She is an author, publisher, and educator.


Wednesday, July 8, 2020

Get Your Chimney Ready for Fall and Winter:

By Marge Padgitt, President of HearthMasters, Inc.

The following are tips for keeping your chimney and fireplace in good order for the season:  

  •  Have all chimneys inspected annually by a professional chimney sweep to be sure they are in good working order. The sweep will inspect the interior with a chimney camera and the entire exterior wood or masonry structure visually.  He/she will look for cracks, gaps, or missing mortar joints in the flue, check for proper flue size, check the smoke chamber and fireplace condition, flashing, crown, and chimney cover. The best time to have this completed is in the spring or summer when chimney sweeps are not as busy.
  • Have flues serving wood-burning appliances swept annually or bi-annually to remove flammable creosote and reduce the risk of chimney fire. All wood creates creosote - even dry hardwoods. 
  • Have the furnace or water heater flue inspected annually by a professional chimney sweep to be sure it is not a Carbon Monoxide risk. Blockages or flues in poor condition can be a CO risk. Even a CO detector does not register all levels of toxic CO gas so it is important that these flues are maintained and are functioning properly. 
  • Have gas direct vent fireplaces or stoves tuned up and serviced annually to assure

    Gas direct vent fireplace
    proper performance. Dirt, dust, and spiders clog orifices and can make the unit inoperable. Annual service is required by the manufacturer for warranty coverage on all brands. This is often overlooked by homeowners and these appliances will malfunction if not
    maintained properly. Change batteries in the sending unit and in the remote control every 3 - 6 months.
  • Make sure that a chimney cover is installed on top of each flue to keep damaging rain and animals out of the flue. A cover should be installed on each flue or a custom-cover can be made to cover all flues and the cement crown. Use a heavy duty stainless steel chimney cover because black steel rusts and will need to be replaced.
  • Masonry problems such as cracked mortar or bricks, deteriorating mortar or spalling bricks should be repaired in the spring and summer months to allow for proper cur

    ing, so plan accordingly.
  • Cement cap with a drip edge prevents
    damages to the bricks belowAdd caption
    Have an elastomeric sealant applied to the cement crown to protect it from weather damage. Cement crowns/caps keep damaging rain water out of the chimney chase. If the crown is in poor shape, it may need to be rebuilt.
Marge Padgitt is a writer and industry veteran. See more information at


Wednesday, June 17, 2020

How an Outdoor Oven can Complement the Rest of Your Backyard Space

By Matt Lee

An outdoor oven can truly complement the rest of the backyard space, as it brings another social element to the backyard and creates a memorable experience. Outdoor kitchens and ovens drastically add to a home’s value, as it makes the space great for entertaining. Below, we’ll chat about how an outdoor oven will exactly enhance the rest of your yard. 

Add Aesthetic Value 

When you integrate an outdoor oven to an entire outdoor kitchen space, your home’s value increases dramatically. You can match the texture and finish to your existing home to ensure that it provides a continuous experience as you’re entertaining. This may mean choosing quartz countertop colors that complement the oven and painting cabinets to match the roof and house color combinations. When it comes to the countertops, they truly must serve a dual purpose in functionality and aesthetic value, as they’ll be exposed to the changing seasons and elements. 

Set Your Home Apart

Now, while more and more homeowners are impressed by an outdoor kitchen space, that doesn’t mean that many homes already have them. Having an outdoor oven will set your home apart and give it a unique touch that your neighbors

are unlikely to have. Furthermore, who doesn’t love pizza?! Wood-fired outdoor pizza ovens are quickly becoming more and more popular, as they’re easy to install and can fit into the design of any existing outdoor backyard. You can take the oven a number of ways, whether you prefer a stainless steel, stucco, or brick look (which pairs well with vinyl cedar shake siding). Homeowners love cooking in wood-fired ovens, as they invite a number of cuisine possibilities and can also help you get outdoors during wintertime. 

Increase Practicality

Aesthetics outside, having an oven and/or kitchen space outdoors makes mealtimes more efficient and facilitates seamless entertaining. While many designers are opting for sliding glass panels between the kitchen and outdoor living spaces, constructing an outdoor kitchen instead brings your home to the next level.

An outdoor oven can add tremendous value to your home. With more and more focus on cohesive living spaces, the outdoor oven will invite your guests outside and add a value room to your home. 


Matt Lee is the owner of the Innovative Building Materials blog and a content writer for the building materials industry. He is focused on helping fellow homeowners, contractors, and architects discover materials and methods of construction that save money, improve energy efficiency, and increase property value.

Tuesday, June 2, 2020

Spring and Summer Bring Pesky Animals into Chimneys

Birds nest inside chimneys where they can cause problems Birds look for dark and safe places to nest and lay eggs in the spring and an open chimney can be an irresistible location for expecting bird parents.

Unfortunately for homeowners, nesting birds inside chimneys can mean big problems. Besides the obvious fire hazard from flammable nests, there may be the constant annoying chirping of baby birds.  And perhaps not so obvious, the health hazard from bird droppings which can contain the disease histoplasmosis.

Squirrels and raccoons also like to keep house inside chimneys and these creatures can cause even more havoc for homeowners. Squirrels are noisy and build large nests that block flues, and raccoons carry roundworm and rabies. If either escapes into the house through a damper, , they may damage the interior of the house.

Therefore, it is best to stop birds, squirrels, and raccoons from entering masonry or prefabricated chimneys in the first place. This can be accomplished by having a heavy duty stainless steel chimney cover with bird screen installed on top of the flue liner of a masonry chimney, or a proper cover installed on a prefabricated chimney pipe. Some older prefabricated chimney pipe covers were not adequately designed to keep birds out of the inner and outer chimney walls, making this type of pipe an even more serious fire hazard.  The addition of a screen in this area will stop the birds from entering but any nesting materials should be removed if found between the chimney walls.

According to the National Chimney Sweep Guild and Midwest Chimney Safety Council, all chimneys should be inspected annually and swept as necessary by a CSIA Certified Chimney Sweep. During the inspection, the sweep will look for nesting materials, dead birds, flammable creosote, and other issues and remove them. Chimney sweeps can install chimney covers that will keep birds and other animals out of flues. Covers come in different sizes and shapes such as individual covers to fit on a single flue or multi-flue covers that cover two or more flues.

It is important to get a chimney cover installed in early spring before birds and squirrels start to nest.  According to the Migratory Bird Act, no nesting birds may be removed from chimneys, and to do so can result in a hefty fine for the homeowner and chimney sweep. If birds do get in a chimney flue before a cap is installed homeowners need to wait until the birds leave in order to have the flue cleaned out and a chimney cover installed. The MCSC advises against using inexpensive black steel chimney covers found at box stores because they rust and stain the chimney. Stainless steel chimney covers are long-lasting, are a deterrent to animals such as squirrels and raccoons, and will never rust. For these reasons it is worth the extra expense to purchase stainless steel chimney covers rather than black steel covers. 

Marge Padgitt is the CEO of HearthMasters, Inc. in Kansas City Missouri. The company designs and builds and maintains masonry heater, brick ovens, chimneys, and fireplaces. Marge is the author of the Chimney and Hearth Pro's Resource Book and others.