Posts tagged with "Chimney Liners"

Chimney Liners: Description, Types, and Importance


At High’s Chimney we’ve found that chimney liners are perhaps the most under-appreciated part of the fireplace and flue system. That’s why we decided to write a little piece giving an overview of their function and importance.

What is a Chimney Liner

A chimney exists to carry dangerous gasses out of the home, and it needs to do so without getting over-heated. A chimney liner creates a barrier between the flue and the walls of the chimney, and its purpose is to insulate and protect the chimney. According to the Chimney Safety Institute of America, a chimney liner is defined as:

“A clay, ceramic, or metal conduit installed inside of a chimney, intended to contain the combustion products, direct them to the outside atmosphere, and protect the chimney walls from heat and corrosion.”

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Why You Should Not Remove 3rd Degree Creosote from Tile Liners

In part 1 of this series, we explained the three stages of creosote buildup. In part 2, we explained how to remove creosote.

Now for the case for not removing 3rd degree creosote from tile chimney liners.

In tile-lined chimneys, it’s the exceptional chimney that has good mortar joints.  In fact, if I were to blindly bet ten people $10 that their chimneys have poorly sealed mortar joints and then we investigated with a closed circuit chimney inspection camera, I stand a good chance of making $100.  I might lose one or two $10 bets, but that’s about all.

The problem with having openings in the system is that liquid creosote can and does go through the joints and/or cracks and accumulates outside of the flue tile.  This is a very serious problem because in a chimney fire this creosote ignites as well and becomes a slow-burning creosote fire not contained inside of a liner.  A house fire becomes a much greater possibility.

It is probably best to consider unsafe any chimney that has had 3rd degree creosote in it, especially if there has been a chimney fire.  Frankly, even if servicemen remove as much creosote as possible, the cleaning does not yield as much safety you’d hope for.

In short, it’s probably best to remove the old tiles completely (getting rid of creosote on the outside of the tiles as well) and replace the liner with a new insulated stainless steel liner.  Here’s why.

The reasons there are bad mortar joints or cracks in chimneys are numerous, including:

  • Some masons “work too fast” and don’t think it’s actually important to seal the joints.
  • The wrong mortar is very often used, or dries too quickly and falls out after construction.
  • The earth is always shifting and the stack of tiles moves over time.  This can open mortar joints and sometimes even crack the tiles.  No matter how good the original job may have been, no one can protect against this.
  • Flue tiles that have contained a chimney fire almost always crack.  They protect the home from fire, but the tiles themselves usually break and mortar is demolished.  This is actually to be expected; it’s the exception if it doesn’t happen.

Before the 1970’s wood heating appliances had lower heating efficiencies.  This was partly because the wood was not as fully consumed, but also because a lot more heat went up the chimney.  This combination usually produced 2nd degree creosote, which is manageable.  Today’s wood burning stoves are very well engineered to get more heat from less wood, and houses are tighter than ever.  Chimneys routinely create 3rd degree creosote (because of the lack of combustion air and the low flue gas temperatures.)

This is why you see so much stainless steel chimney lining done these days.  The chimneys of America are undergoing change as they are being properly sized to their appliances, either by upgrade or by repair.  The stainless steel liners are:

  • The right size for whatever appliance they serve.
  • Flexible enough to shift with the earth.
  • Able to withstand chimney fires without breaking.

Installing Chimney LiningOne reason why more people don’t reline is that reline jobs may cost more than people were planning for; another reason is that many folks just don’t understand the need.  It’s going to take a long time to convert America’s chimneys if either insurance companies or building codes don’t speed up the process by insisting that people change over to a stainless steel liner (or not be allowed to burn wood).

About Chimney Creosote – Part 1: The 3 Stages of Creosote

What is Creosote?

Creosote is actually just one of the components in the stuff (aside from the ash) that’s left over when wood is burned.  The whole mix of tar and creosote and soot is commonly called creosote.  The term is almost exclusively used when talking about burning wood.  If discussing soot resulting from burning oil, or even gas, this is just soot and it’s just called soot.  Though the black residue in the chimney from burning wood is called creosote, it is in fact mostly tar.

There are, generally speaking, three types of creosote are found in chimneys and they are usually called ‘stages’ or ‘degrees.’  All three forms are all combustible and should be removed.

First Degree Creosote Buildup

First degree creosote has a high percentage of soot and can be removed from a chimney effectively with a chimney brush.  First degree creosote develops when there is a relatively good combustion of the wood and/or relatively high flue gas temperatures.

This describes an open fireplace.  The burning wood had lots of air for the combustion process and the heat flies up the chimney.  These are best conditions for a chimney.

Second Degree Creosote Buildup

Second degree creosote is a bit trickier.  This creosote buildup is generally in shiny black flakes.  Imagine dry, hard tar corn flakes, and in greater volume than first degree creosote.  It’s not as easy to brush away, but still fairly removable.  It would be difficult to describe all the situations where 2nd degree creosote develops, but suffice to say it will occur where the incoming air is restricted.   This describes woodstoves and fireplaces with glass doors.

Third Degree Creosote Buildup

Third degree creosote buildup is the worst of them all.  This occurs when the flue temperatures are low and/or combustion is incomplete.  This is common when any of, or a combination of, these conditions exist:

  • On woodstoves with the air controls turned way down
  • Un-insulated chimneys (or any other reason the chimney is cold)
  • When using unseasoned wood
  • If the flue is oversized for the appliance
  • When the house is tight and can’t draw sufficient combustion air

Third degree creosote looks like tar coating or running down the inside of the chimney.  It is extremely concentrated fuel.  It can get very thick as it hardens and is recoated over and over.  An inch thick would be unusual, but it’s not unheard of.

And worse yet is third degree creosote that fills up “chimney fire fluff.”  If creosote buildup catches fire in a chimney, maybe it burns away completely but more often it does not.  More frequently the creosote partly boils, partly burns and leaves a dried out light-weight “sponge,” often more than 2” thick which is actually very easy to remove.  But if it is not removed, new third degree creosote fills that sponge you can have well in excess of 100 pounds of creosote in a chimney.

The first chimney fire may not have damaged the house, but that next chimney fire will be fiercer than the first and exceptionally dangerous.  The really tough part is that third degree creosote, in any form, is very hard to remove.

We’ll discuss ways to remove creosote in Part Two.

Masonry Chimney Repair & Relining

Masonry Chimney Repair & Relining

The Washington DC area has a rich history of architectural styles. From brick farmhouses in Fairfax to Victorian row houses in Georgetown, Washington DC has preserved much of its architectural history. These homes have weathered decades (or centuries) of use, remodels and updates while still possessing an undeniable charm. The sturdy construction of these historical buildings plays a large part in their continued existence, but constant monitoring and maintenance is what keeps these charming homes instead of quaint historical exhibits.

Routine inspections and preventative maintenance can help keep houses old and new running smoothly. For many components of your home this can be a simple process. For example, wear around your windows and persnickety plumbing are easy to spot. For other parts of your home, such as your chimney, a little effort is required.

Chimney Masonry Maintenance

Most responsible home owners ensure they have a proper flue with optimal draft and that the major components of the fireplace are functioning properly. This diligence causes the illusion of security; so long as no major problems occur, their chimney must be healthy. In reality, without a watchful eye, water damage can compromise the integrity and safety of your chimney long before you notice the problem. While the rest of your roof is protected from the elements, your chimney is exposed to the worst of Mother Nature.

While the brick itself generally fares well against such odds, without water proofing the mortar is heavily susceptible to water damage. Specifically, mortar absorbs moisture. As the temperature changes, freezing and thawing cycles cause this water to expand and contract, which will cause cracking. This damage is often subtle, and by the time you notice crumbling mortar you will likely need masonry chimney repair. As it progresses the mortar will erode out from between the bricks, causing their weight to shift. This causes additional stress on the masonry, and exacerbates any existing cracks or stress points. Without proper care, mortar erosion will cause an unsafe and unsightly chimney that will need major masonry chimney repair. At this point a chimney professional will need to repoint the brick, and apply a waterproof sealant to prevent future water damage.

Masonry Chimney Relining

Chimneys suffering from masonry damage can let an excessive amount of water into your chimney’s interior. If you actively use your chimney as a vent, this can affect your flue, fireplace, and any appliances that vent into the chimney. For example, rain running down a used flue will mix with creosote and other deposits, causing a corrosive solution that can deteriorate your flue. This corrosive solution can drip down onto fireplace hardware, such as dampers, and rust them. Even if your chimney is perfectly clean, rain water will settle into any joints or cracks in your flue, where temperature changes will cause it to expand or contract, causing damage. This will cause a premature need for chimney relining.

Even if you don’t use your chimney as a vent, masonry chimney repair is important. Crumbling mortar allows moisture to permeate to the interior of a chimney. Inside the chimney, it will run down the joints in the masonry, leaking into cracks. This compromises the structural integrity of your chimney, which is never safe. Relining and repointing the interior of a masonry chimney is an expensive and time consuming process. To be able to work in such tight spaces, it’s often necessary to punch holes in the chimney to be able to ensure the proper work has been done.

If you have questions about masonry chimney repair or suspect you might need masonry chimney relining, contact us at High’s Chimney. We want your home to be a healthy, safe place to live. We offer free consultations on masonry repair, and our real time online scheduling service makes it easy for you to pick a time that works with your schedule. Being proactive about problems as they arise, such as masonry chimney repair and relining, is the best way to ensure your home remains a safe and stylish place for you and your loved ones to enjoy for years to come.

Types of Chimney Liners

About Chimney relining: Types of Chimney Liners

No matter what sort of chimney lining you have, in time it will need to be maintained or relined. Understanding the three major types of chimney liners will help you discuss with a trusted professional the best way to line your chimney and keep your home safe and sound.

Clay Tile Chimney Liner

Clay Tiles have been a historical favorite for lining chimneys. As such, most older homes have clay tile liner. These were popular for a variety of reasons, the most important being that clay tile insulation with properly finished mortar joints can withstand most types of smoke and can last up to 50 years.

In today’s world, however, these tiles are not the perennial favorite. Studies show that during a chimney fire, even the most well finished mortar joints are likely to crack, and usually break apart. Any crack in your chimney lining makes it more likely that the fire could spread to the rest of the building.

Clay Tile Chimney Liner

Clay Tile Chimney Liner

Additionally, repairing or relining a chimney with clay tile is a very difficult task. Punching holes in the chimney to ensure the tiles are aligned and joined correctly is often necessary, and such effort is costly. For this reason, when most home owners notice cracks or problems with their clay tile chimney liner, they transition to a different liner entirely.

Cast in Place Chimney Liner

Cast in place liners were created around 60 years ago. While initially they were highly-regarded, over time their popularity has decreased due to a high likelihood of cracks.

One benefit of the cast-in-place chimney liner is the insulative properties of the material. The insulation helps keep heat from leaking from the chimney, and higher temperatures in the chimney helps ensure creosote, soot and combustive gases are more fully consumed, which means less accumulation inside your chimney, and fewer emissions from your chimney.

The downside to this chimney liner is again cost. Installing the liner can be expensive, and if you have any bends in your chimney, the price is just going to go up. A professional will also need to determine if any existing chimney liners need to be removed prior to chimney relining. Also, as cracking develops, the process of relining is expensive and time consuming.

Metal Chimney Liner

Relining Chimney with Metal Liner

Lining Chimney with Metal Liner

Metal liners are by far the current favorite of the construction world. They come in a vast array or shapes and sizes, and can either be rigid of flexible. Installation and parts are generally inexpensive, and with proper maintenance metal liners often outlast the house. Also, as appliances within your home change and chimney liners adapt to meet these changes, replacing your chimney liner with an up to date metal liner is an easy and logical process.

Reasons for Relining
The largest reason for chimney relining is improper liner sizing. Improperly sized lining can lead to soot and creosote deposits and improper draft, both of which are safety hazards. Proper chimney lining size is a difficult variable to determine, so if you have any questions about the best size chimney lining for your home, contact a chimney professional.

The second largest cause of chimney relining is cracks and breaches in the lining itself, which is a large fire hazard. At the first sign of cracks or damage, call in a professional to ensure your home is safe. Remember, even if you stop using your fireplace, other appliances may vent into your chimney exposing you to potential danger.

Benefits Of A Stainless Steel Chimney Liner

Chimney liners are a vital element in the operation of your fireplace or wood stove. And when the liner has deteriorated, cracked or aged beyond its limit you have a choice of materials for the replacement chimney liner. Clay tile is a traditional choice for the liner, although you can also choose cement or aluminum. Stainless steel chimney liners are a popular and durable choice that delivers various benefits.

Long Lasting

Because stainless steel is corrosion resistant you can expect this liner to last for years virtually problem free. And the complete seal applied to the liner keeps nasty emissions away from your masonry, allowing them to last longer and cutting down on required repairs.

Affordable

A stainless steel chimney liner an affordable alternative to most traditional chimney liners. Easier to install than clay tile liners, the initial installation of stainless steel liners is less expensive. Also, chimney sweeps have an easier time cleaning this type of liner thanks to the round shape. No square corners to catch deposits of creosote makes for a faster, more effective clean. In the end, this should cost you less.

Sealed and Smooth

Aged clay tile chimney liners will crack and split, which allows noxious fumes to leak into your home. With a stainless steel liner you will effectively seal those cracks and drastically reduce the chance of them happening ever again.

Added Insulation

Insulation can be fitted around the stainless steel liner or stuffed between the liner and the chimney walls. This insulation cuts down on creosote build up by keeping the air hot all the way up the chimney. It also helps to reduce the cold air draft that could come down the chimney when the fireplace or wood stove is not in use.

Replacing your existing liner with a new stainless steel chimney liner is a wise choice, offering your home all of these benefits and not to mention, a whole lot more.

All About Your Chimney Lining

Lining your Chimney

Why are so many people having their chimneys relined these days? As cold weather approaches and you fire up your heating system, wood stove or fireplace, are you thinking about the inside of your chimney system?  In a perfect world, the inside of a chimney is something you’d never have to think about. Unfortunately the world isn’t perfect and many masonry chimneys aren’t either! Let’s discuss what can go wrong inside of a chimney and how chimney liners figure into it.

A chimney’s purpose is to carry the flue gases out of the home, and it needs to do this without getting over-heated. The problems with the inside of chimneys falls into two general categories: the problems that cause flue gasses to back into a house (smoke or carbon monoxide) and the problems that can cause house fires.

Most masonry chimneys are lined with fireclay tiles. This material has been used for 100 years and was a huge improvement to unlined chimneys of the 1800’s and before. In fact they served well enough until the 1970’s. Here’s what happened.
chimney lining

As people became conscious of the cost of heating, they started to put glass doors on the front of their fireplaces. This changed the fuel-air ration that had existed for eons. Suddenly masonry fireplaces that had never had problems before got full of soot and creosote in a matter of months.

Fireplace inserts caused the same problems, only even more so. The stoves were engineered for flue openings of six or eight inches round but were venting into chimneys built for open fireplaces. And fuel-air ratio was now so low that many chimneys collected a thick, wet, gooey tar. In some cases, chimneys were catching on fire within weeks after the stoves were installed!

Obviously the same was true for freestanding woodstoves.

And what about central heat flues, that is gas and oil? Well, those appliances changed too: they became much more efficient. The problem there isn’t creosote, as these fuels burn much cleaner. But it takes a certain amount of heat loss in the chimney to take the fumes up the flue and it wasn’t there anymore.

Three bad things happened to the masonry chimneys:

  1. More heat was delivered into the home and the flues didn’t have enough heat to carry the gasses up and out!
  2. The water in the exhaust condensed in the flues (instead of in the atmosphere). The inside of gas heaters in particular got very wet. Very, very wet indeed: so wet that they could freeze in the winter and block up, or so wet the wall paper inside the house was peeling where the chimney passed by. So wet that the freezing and thawing deteriorated the outside bricks themselves!
  3. And carbon monoxide levels in the houses skyrocketed! Tens of thousands of people a year are affected by CO poisoning and many don’t even realize it. They just don’t feel so great; lethargic or as if they have a cold. And of course there are even deaths… it’s a bad situation.
    • For reasons more technical than this article will cover, a properly sized liner will extend the appliance life and its heating efficiency. This is true for both central heaters or wood burning appliances.
    • For gas flues you can use aluminum but it often doesn’t have a very long life with modern appliances. The best material for lining a chimney, whether gas, oil or solid fuel, is stainless steel. #316 is a very good alloy for chimney lining and is readily available.
    • The liner must be properly sized to the appliance for it to work properly. Either too big or too small is not good enough. Don’t get this wrong.
    • There are three systems in your home that can kill you: electrical, plumbing and venting.  Unless you really know what you’re doing, unless you’re the kind of do-it-yourselfer who’d dig up his own sewerage system etc. don’t try to do it yourself. While anybody who can work with tools can theoretically do anything, there are enough things to go wrong with a venting system that this isn’t something you should tackle yourself. Hire a professional.

    Add to this that in most cases tile chimneys are not particularly well sealed in the first place, just because that’s the way they’re built. Also, many homes now operated under “negative pressure.” That means that our airtight windows and doors, our weather stripping, and our fans in the house all conspire to prevent good draft in chimneys. All of these factors combine to create the need for smaller, positively sealed venting systems.

    This is where chimney liners come in. The info above pretty well describes why you need a modern chimney liner. Lining your chimney with a good stainless steel liner will pay you and your family dividends both in dollars and in vastly increased safety.  Make it your next home improvement!