Avoiding Litigation: Chimneys

By Keith Swift, PhD
InterNACHI member/InterNACHI Report Writing Consultant
President, Porter Valley Software

The word chimney is actually a misnomer that has come to include every component from the crown to the footing and everything else in between. However, there are two basic types of chimneys, prefabricated metal ones, and masonry ones that are either built on-site or pre-cast in factories to be trucked to a site or erected as a finished unit. Chimneys are primarily heating systems that sustain the combustion process and the release of heat. Their use, and certainly our inspection of them, involves a certain degree of risk that is generally proportionate to their age and type, and to the climate in which they function. For instance, an old, coal-burning, single-walled, brick chimney on the East coast is far more likely to be suspect than a similar unit on the West coast that vents an ornamental fire. Regardless, chimneys are complicated and feature prominently in lawsuits. For this reason, I include an educational narrative with every chimney that I inspect.  I don’t regard the narrative that follows as being the best possible, but if you don’t have one that is better you are certainly welcome to use it, and any others that appear in this article for that matter. My report writer includes literally thousands and thousands of narratives that I am constantly revising in one way or another, in order to better educate my clients and to shield myself from the ever-present threat of lawsuits. This is what my reports say about chimneys in general:   

“There are a wide variety of chimneys, which represent an even wider variety of interrelated components that comprise them. However, there are three basic types: single-walled metal, masonry, and pre-fabricated metal ones that are commonly referred to as factor-built ones. Single-walled metal ones should not be confused with factory-built metal ones, and are rarely found in residential use, but masonry and factory-built ones are a commonplace. Our inspection of them is that of a generalist, not a specialist, and meets industry standards. However, significant areas of chimney flues cannot be adequately viewed during a field inspection, as has been documented by the Chimney Safety Institute of America, which reported in 1992: ‘The inner reaches of a flue are relatively inaccessible, and it should not be expected that the distant oblique view from the top or bottom is adequate to fully document damage even with a strong light.’ Therefore, because our inspection of chimneys is limited to those areas that can be viewed without dismantling any portion of them, and does not include the use of specialized equipment, we will not guarantee their integrity and recommend that they be video-scanned before the close of escrow.”

Such narratives are essential to any report, and although most of our clients really don’t need to be told that there are parts of a chimney that cannot be seen with the naked eye, it doesn’t hurt to remind them and their prospective attorneys. However, the real problem with disclaimers is that they can leave inspectors with a false sense of security and prevent them from doing a more conscientious inspection. Besides, a disclaimer is no defense against a charge of negligence. Therefore, inspectors should decide in advance which chimney components represent a threat, and which are worthy of a careful evaluation, so that a disclaimer does not also become a trap. For instance, just because inspectors might disclaim an evaluation of a flue because portions of it may not be visible, this should not stop them from getting their head and shoulders inside a fireplace to get the best possible view of the smoke shelf. I’ll illustrate this by telling you about a chimney that I inspected recently in an expensive and completely remodeled house. Viewed from the roof, there was nothing remarkable about the chimney. It was a lined type that met the 3-2-10 drafting rule, and included a cricket, tight flashings, and a spark arrestor-weather cap combination. I had a perfect view of the liners, which were pristine and doubtless hardly ever used. The hearth and its surround appeared to be new, as you can see in the first picture. I didn’t get my head and shoulders inside the fireplace because I was satisfied with everything that I had seen so far, and was hesitant to remove and replace the objects that you can see on the hearth. Besides, the back and sidewalls appeared to be perfect, and the log-starter not only responded but also included an ornate, gold-plated key. Someone had obviously spent a ton of money on the renovation. However, just as I was about to get on with the rest of inspection, I imagined hearing the voice of an attorney: “Tell me, Sir, did you even attempt to look at the smoke shelf?” I hesitated, and then imagined hearing the voice of my wife: “Well, did you?” Goaded into action, I cleared the hearth, slid my head and shoulders inside the firebox, and saw what you can dimly see in the second picture: which is a separation adjacent to the lintel that is big enough to qualify as an attic access! The first fire in this fireplace certainly would have been the last, because it would have likely burned the house down! Later, I showed the picture to my wife, and basked in her praise, knowing that even a schoolboy could have identified such a mind-boggling hazard! Oh the power of paranoia and the voice of my pretty wife!

Needless to say, every visible chimney component should be examined carefully. The single-walled metal flues that remain in use today are rare, and are mostly found in rural areas. They can get hot enough to burn the skin, and represent a significant hazard. Therefore, inspectors would be well advised to disclaim an evaluation of them, unless or course they are well acquainted with their parts, and with the local ordinances governing their use. Even then, I recommend including a cautionary narrative warning clients about such dangers. By contrast, modern factory-built metal chimneys are among the safest, but because they are assembled on-site, and not always with factory-approved components, they tend to generate a disproportionate number of disputes. Interestingly, many of the defects that I’ve heard about were readily apparent without dismantling any portion of them. One that I i nspected recently was missing the transition between the firebox and the flue, which was plain enough for anyone to see. However, the chimney had been signed off five years earlier when it was installed, and presumably when the firebox and flue were exposed to view. Furthermore, I was told that it had also been approved by an inspector who still remained liable under a four-year statute of limitation.

Masonry chimneys can be equally suspect. There are three basic types, one that is lined, and one that is unlined, and a third that is pre-cast in a factory as an integral unit and trucked to the site to be erected. Obviously, regional concerns dictate which chimney is best. In earthquake country, people would obviously prefer not to have a two-story masonry chimney towering above them, or a single-brick one for that matter. And in regions where fossil fuels are burned continuously, one would rather have a lined flue to resist the corrosive effects of degenerative flue gases. However, before we elaborate on the distinction of lined and unlined chimneys, we should consider the pre-cast one, which is also referred to as a tilt-up, and which I describe to my clients, as follows:
 
Pre-cast concrete chimneys are built in factories and then trucked to a building site and erected, as distinct from masonry chimneys that are built on site with individual bricks and mortar. In this respect, pre-cast chimneys are unique. However, like masonry chimneys, they are vulnerable to seismic activity, but unlike masonry chimneys they are also subject to cracks that are induced by the interaction of moisture and a chemical additive called calcium chloride that causes the reinforcing steel within the chimney to expand and crack the chimney wall. Such cracks can be small, but they are nonetheless subject to stringent repair methods that are stipulated by the manufacturer. However, if any crack penetrates the chimney wall it cannot be repaired and the chimney must be removed. For this reason, we recommend that all pre-cast chimneys be video-scanned or certified by a specialist before the close of escrow.

This narrative is self-explanatory and needs no further comment, so we can move on to a discussion of the inspection process, which typically begins on the outside. Based on the age of the residence, you will have an idea of how old a chimney is likely to be, which could affect your evaluation of it. However, you should identify it as being interior or exterior, single-story, two-story or multi-level, metal or masonry, lined or unlined, so that you can select an appropriate narrative from your report-writer to include with your evaluation of its components. Next, you should look for cracks in the walls or bent flashings that could confirm structural damage. Then you should examine it from on the roof. The first thing that you want to make sure is that it meets the 3-2-10 rule used to predict drafting, which states that in order to draft well a chimney should extend at least three feet above the roof, and two feet above any point measured in a ten foot radius. If the chimney is an exterior type, you may wish to test it for movement by rocking it gently. Strength is not a factor in this regard, and you should exercise extreme caution. Exterior masonry chimneys will permit some movement, but you should be able to decide that which seems normal and that which seems excessive, and what might be described as a hinge-effect, and to decide whether any such movement is being permitted by common structural breaks at the roofline or further down at the shoulder, and report it as such. It is also important to examine the chimney walls for any evidence of cracks or washed out mortar joints. Something as simple as reporting on washed-out mortar joints could prove to be an important observation, and especially when there is little else to report on, because it would confirm that you examined the chimney walls carefully enough to make a detailed observation. Although not exposed to weather, the chimney walls inside an attic should also be examined carefully. Chimneys are structurally independent, and there should be two inches of airspace between an interior chimney and any combustibles, and one inch of airspace on exterior ones. Now, let’s consider some of the common components.

The mortared crowns on masonry chimneys are shaped to shed the moisture that can deteriorate flues. They should be examined to insure that they’ll perform well, and recommended for service if they are damaged or deteriorated. Weather caps and spark-arrestors need no explanation. I always attempt to remove them to get a better look at the flue, or I indicate in my report that I was unable to so. However, for aesthetic reasons, some builders elect to enclose the top of factory-built chimneys with a decorative shroud, which is usually not part of the installation package. Such shrouds can inhibit drafting and convectional cooling, which is essential for the performance of chimneys, and should be removed if it they are not a factory-approved component. Regardless of the chimney type, the liner is the most critical component. Chimneys that have liners are the most dependable, whereas unlined and single-walled chimneys remain suspect. For instance, The Chimney Safety Institute of America states: “all unlined chimneys, irrespective of fuel used, are very liable to become defective through disintegration of the mortar joints.” And this is equally true of the mortar that is used to parge the walls of unlined flues. However, this is not a reason to condemn all unlined chimneys. Those in warmer climates that are in good condition, and are used either infrequently or only to vent ornamental fires, should not be categorically condemned. Regardless, inspectors are ethically obligated to report everything that they know about a particular chimney type, if only to safeguard their clients from dishonest people who might try to take advantage of them. Some real estate agents don’t appreciate such information, and typically dismiss it as being boiler-plate, when in point of fact it can be essential information that confirms an inspector’s professionalism.

They are different types of flue liners, but the most common are made of metal or vitreous clay. Such liners provide a vent to the exterior and a thermal barrier that protects the chimney walls from the degenerative effects of flue gases. Although the flues of unlined chimneys are commonly plastered with mortar, which is intended to have the same effect as a liner, it is generally agreed that mortar is a poor substitute that is in no way comparable. Significantly, flue failures are the most common cause of chimney fires, but liners that were either installed incorrectly, degraded by weather, seismic activity, or thermal extremes, have also contributed to such failures, and it is critical that they be examined carefully. Damage is typically apparent in two forms, either as a loss of material, which is referred to as spalling, or as longitudinal cracks. Both typically result from moisture contamination, thermal extremes, or both, which could predicate a chimney fire, and should be reported. Remember, a crack in a liner might appear to be small and insignificant, but they can become extremely wide and vent combustible gases, when a fire is raging.

Damage or separations to prefabricated metal flues are equally dangerous. Such damage could be apparent from within the attic where the flue might be exposed, but many chimneys installed since 1992 are required to have their flues enclosed in insulated chases. If the flue is exposed, examine it carefully, and make sure that each section is supported and that there is a sheet metal fire-block surrounding it on the attic floor to isolate it from the oxygen-rich atmosphere of the attic. The best possible view of a flue, other than from the top down with the termination cap removed, is from within a fireplace. You would need a strong flashlight, and position your head and shoulders inside the fireplace. However, before you wiggle inside and look up, test the damper to make sure that it is functional and releases any debris that might be present, such as soot, twigs, and the occasional rodent, reptile, or dead bird. When you do look up, you should confirm that there is a smooth transition between the firebox and the flue, and that there are no gaps between the flue and the chimney wall that would permit flames or combustible gases to penetrate. If angles or anything else obstruct your view of the entire flue, you should make sure that your report indicates this and disclaims an evaluation of it. However, before moving on to a discussion of other components, it is worthwhile mentioning the by-products of combustion that contaminate chimneys. These contaminants are usually grouped under the common term creosote, the nature of which is not fully understood, despite advances in chemical knowledge. Regardless, disputes over chimneys commonly start when a client calls in a specialist to have a flue cleaned. Some of these so-called specialists take this opportunity to sell people components or services that they may not need, by alarming them about the threat of chimney fires. And inspectors can never hope to prevail against the testimony of a specialist, and must protect themselves as best they can with sensible disclaimers, such as the following, which I include with every chimney evaluation:

Chimney flues need to be cleaned periodically, to prevent the possibility of chimney fires. However, the complex variety of deposits that form within chimney flues as a result of incomplete combustion, and which contribute to such fires, are complicated and not easily understood. They range from soot, or pure carbon, that does not burn, to tars that can ignite. All of these deposits are commonly described as creosote, but creosote has many forms, ranging from crusty carbon deposits that can be easily brushed away, to a tar-glazed creosote that requires chemical cleaning. These deposits must be identified and treated by a specialist. However, cleaning a chimney is not a guarantee against a fire. Studies have proven that a significant percentage of chimney fires have resulted within one month of the chimney being cleaned, and many more have resulted within a six-month period.

Some forms of creosote actually confirm that a chimney fire has occurred. The resulting deposits often look like expanded tar bubbles, foamy or sponge-like deposits, and thin, flaky wafers that collapse at a touch. However, they can reduce the diameter of a flue and impede drafting and convectional cooling, and whenever you see any such deposits, you should recommend that the chimney be evaluated by a specialist and serviced as necessary. I actually take a few extra minutes to study and attempt to interpret carbon deposits within a firebox to see what they can teach me. Sometimes, the evidence of a fire can be clearly visible inside a fireplace, which I’ll explain next.

Sometimes referred to as an appliance, a fireplace has its own foundation, which is comprised of a floor, an ash pit, or cleanout, a firebox, or combustion chamber, with a smoke chamber that provides a mitered transition into the flue, and a hearth and hearth extension. Fireplaces are typically lined with refractory brick, or with prefabricated metal or terra cotta panels that contain the combustion process. Soot or carbon deposits surrounding the firebox could confirm that the chimney does not draft well, such as is obvious in the picture, but you should look for other indications that a flue may not draft well, such as restrictions within the smoke chamber or an inadequate distance between the lintel and the flue. Regardless, any damage to the firebox should be described in detail, such as thermally warped metal panels and loose or missing refractory bricks. Some cracks in refractory bricks are relatively common, but any cracks in the firebox of a pre-cast chimney, and particularly those in a breastplate are serious, and should be referred to a specialist. It is not uncommon to see separations contouring the opening, which can literally draft a flame in much the same way that a flue does. These should be sealed, and particularly if combustible material surrounds the firebox. In fact, every crack or void in a firebox should be described. For instance, it’s common to find voids in the sidewalls of factory-built chimneys where a gas pipe penetrates, but these can also draft a flame beyond the combustion chamber and should be sealed with thermal caulk. Remember, any breach of the firebox is a safety hazard. But, also remember that you are a generalist and not a specialist. Therefore, report even the slightest defect, and don’t hesitate to recommend a specialist evaluation.

It is important to turn on ornamental logs and log-starters, at least long enough to smell the gas and confirm that they are functional. Other than that, there is little else to do except to report on their overall condition. This brings us to the end of our discussion about chimneys, but a few more words of caution for the novice inspector. Quite frankly, although I am willing to endorse any single-story lined chimney, providing that I have a reasonable view of each liner, I will not endorse any other masonry chimney. My reasons are simple. Experience has taught me that there are too many so-called specialists who, whether by ignorance or greed, fabricate deficiencies and fuel disputes and lawsuits. This is particularly true with clients who would rather believe the worst, and it is nearly impossible for any inspector to prevail against the testimony of a specialist. However, even if you do happen to prevail in a lawsuit it will still cost you, one way or another. Therefore, smart inspectors will avoid disputes at any cost, and the only way that they can do this is by conducting a conscientious evaluation, and by including totally rational disclaimers and carefully constructed observations in their reports.