Posts made in July 2012

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).

How to Remove Creosote – About Creosote Part 2

As mentioned before in this series’ first post about creosote, there are three degrees, or stages, of creosote buildup. Chimney brushes are the standard method for removing first and second degree creosote.

chimney brush

However, sometimes second degree creosote will be hard enough to remove that other methods would work better:

  • There are flat wire brushes which are pretty effective.  They are expensive.  If there’s a very thin coat of creosote on the chimney wall a flat wire brush will do a fair job of removing that too.
  • There is special equipment for just this type of creosote.  A rotary loop which is a stainless steel cable fixed to a hub that is put on special metal rods turned by a powerful drill (this process burns up regular drills) This method is quite effective.
  • There are chemical creosote removers.  They come in two kinds: the ones that take time and the ones that work fast.  So said, “fast” still means a couple days.  Fast chemicals definitely work, but they are not used much just because of the safety considerations and the expense of the return trip involved.  They are very caustic and they can make a very big mess.
  • Other chemicals, such as ACS or CreAway are effective over time, but are most useful as good maintenance.  CreAway can actually reverse many problems given some time (weeks to months) provided one changes his burning habits.  Continuing to burn the same way as you did to develop the problem in the first place has to stop if you want your chimney to clean up.  (Consult your chimney sweep or the stove’s owner’s manual for best burning practices)

Third degree creosote removal is the most challenging of all.  And sometimes it’s not worth removing the creosote- there’s often a very good case to be made for taking out the old chimney liner and putting in a new and different one.  But first the removal options:

  • The chemicals mentioned above can work if the creosote hasn’t been on fire.  If the chimney walls just look like they have been coated with tar, the chemicals can work.  The caustic chemicals, if used at all, are usually reserved for this type of problem.
  • The flat wire brush and the rotary loop don’t stand a chance.
  • If the creosote is hard there is a rotary head with chains that will do a rather effective job.  Contrary to intuition, the chains will not break flue tiles.  However, in chimneys that have been abused so that there is 3rd degree creosote the tiles are very often already broken.  As a general statement it’s hard to find a sweep that will do rotary-chain-cleaning because he’ll get blamed for breaking the tiles.  Even so, this is an option, and probably the most effective immediate-removal option.
  • And sadly, you should probably have low expectations for how clean the chimney can ever be again.  Once it’s been full of 3rd degree creosote, even specialized removal tools can get the chimney only so-clean.

In Part 3 we’ll discuss why it’s not a good idea to try to remove 3rd degree creosote from a tile chimney and then reuse it.

High’s Chimney Service named a 2012 Best Pick by EBSCO Research

Recently, High’s Chimney Service has been named a 2012 Best Pick by EBSCO Research, an independent consumer research firm that produces the publication Best Pick Reports. Currently, High’s Chimney Service is a 2012 best pick for Chimney & Fireplace work in the Montgomery County region, as seen here. As of right now, we’re the only chimney company in the area to earn that distinction.

We’re pretty proud of that.

A little while ago, Best Pick Reports shared with us 15 pages worth of reviews from customers of High’s Chimney that it had independently compiled. We’re happy to say that most are grade A reviews, and we received an A average, although we’ll admit there are some reviews that indicate room for improvement. But we take feedback seriously. Making the perfect chimney company is a never-ending process. By the way, if you’d like to share your experiences on High’s Chimney Service, please visit

And, if you’d like to see the full list of reviews compiled by Best Pick Reports, read on, because we’ve included each and every one of them below, unedited.

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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.