How to Tell If a Chimney is Structural – Don’t Underestimate Experts Tips


The question of whether a chimney is functional or non-structural is a significant concern for the majority. As the defragment of chimneys might be vulnerable for building infrastructure. Structural chimneys are primarily made of silicate bricks. They have a solid upward draft that draws out the byproduct that is produced by burning fossil fuel. The gases released are then emitted through a flu-like part that is concealed in the masonry. Additionally, a chimney pot is situated at the roof of the chimney cap. It also contains smoke, a firebox, as well as the base assembly. Haven’t got your answers? Still, now you are thinking about how to tell if a chimney is structural? Don’t worry. We’ve provided you with a complete outline to address all of your questions. Keep an eye on our guidelines. Please keep your eyes open to read our tutorial.

How to tell if a chimney is structural

How to Tell If a Chimney is Structural

Protect the chimeny

The chimney must protect by an aluminum or concrete cap 50 millimeters greater on all sides than the chimney. The chimney draft directly link to the structural condition in the building of the brick chimney. Consequently, a lower chimney draft can cause an increase in the temperature of the flue gasses, which in turn results in the formation of condensate. The chimney draft decreases with the strength of the structure and the natural long-term functioning of the chimney. If the system isn’t fitted with forced air ventilation, the repair of facades and repair of chimney openings could cause deterioration to the draft of the chimney. To prevent this, it is advised to have adjustable vents installed in the exterior wall to allow the combustion oxygen to flow into the building.

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Construct the chimeny

The combustion chamber and chimney should construct and desig so that the flue gases heated at the outlet will not drop below 100 degrees C. If liquid fuel (oil gas, gas, etc.) is used for heating in the furnace, The flue gas temperature keep below 100°C. In addition, the flue gas has a low temperature and a huge volume of water that is contained inside the gas. The liquid contained in flue gas condenses within the chimney on the flue pipe’s cold internal surface. Condensate (sulfuric acid solution SO2, SO3) can cause corrosive effects and disrupt the smoke channel’s functioning. So, all oil boiler manufacturers advise using pipes resistant to acid (stainless steel or ceramic materials) for these heaters’ chimneys.

Heat with a limit

Heating a structure in winter because of the huge temperature differential within the chimney. It is a situation where the liquid inside the chimney push out onto a colder, colder surface outward. If the joint is made of stone that is thicker than 120 millimeters, the drying process takes between 3 and one and a half years. In addition, it helps to create the clustering of dampness within the stack.

The cold of the night quickly chills the chimney following the furnace has finished, humidity builds up on the outside of the duct, and within the stone, seams begin to crystallize (ice crystals form). As ice crystals form, it increases the volume, which in turn causes internal stress. Due to the internal stress within a silicate block, cracking or surface destruction of the whole stone occurs at a thickness of around 120 millimeters. It is therefore recommended to build the chimney within our climatic zone before the start of September.

Fire safety

Heating should only conduct using dry wood that has not more than 20 percent moisture content. When installing the chimney, when laying the chimney, Fire Safety Requirements for Buildings EVS 812-3: 2007 and just follow the fire safety act. In Estonia, silicate bricks are mainly used to cover the chimney’s exterior. An acid-resistant, anti-corrosion stainless steel sleeve should be put into the duct. The inner lining of the duct was constructed out of silicate stone laid over a sturdy cement mortar (T100 300). The chimney’s edge is secured by a painted or galvanized metal cap or Slanted grout cover.

Factors to consider to tell a chimney are structural

There are many kinds of chimneys that use in our homes. However, not all are structural components of houses. Both types of chimneys, namely prefabricated and masonry chimneys, are considered to be structural chimneys. How to tell if a chimney are structural and what factors you must consider. In this section, we’ll examine the various factors that can help determine the types of chimneys that are structural. There are several standard features to recognize a structural chimney.

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Chimney pot

Most chimneys’ have a cap made of concrete. It’s an extension place at the top of your chimney’s stack. In the case of structural chimneys, they are fitted together with chimney pots. These chimney pots are a little different from the caps, as the name implies. They’re usually located in the uppermost part of the chimney’s smokestack. They are often found over chimney caps, with a small vertical extension. They extend the smokestack, resulting in an improved draft to allow for better combustion.

For structures chimneys, they fitt equipped with chimney pots. These chimney pots are slightly different from caps, as the name implies. They’re typically located at the highest point on the smokestack of the chimney. Sometimes, they’re located over chimney caps and have a slight vertical extension. Thus, they extend the smokestack and provide more drafts to ignite.

Chimney draft

What does the term “chicken draft” refer to? When a chimney fill with gasses, it begins to rise. This is because the gas inside is much lighter than the exterior air. When the hot gases cause the pressure divergence, also known as chimney draft, it draws the air from the fireplace and then releases the gas to the outside. If a structure fitt with forced air, then you must be aware. If not, the draft can damage when repairing the facades. In addition, the replacement of the openings could impact the draft severely.

Flue gases’ temperature

The structural chimneys are built to ensure that the temperature stays within a range of 100 degrees Celsius. Their design must provide the temperature does not fall below the standard limit. The degree of temperature maintained is contingent on the type of fuel utilized. If liquid fuels like gas or oil are used, and temperatures remain below 100°C. It’s due to their lesser burning capability compared to wood.

Typically, the gas fireplace is employed to heat the house. However, nowadays, a variety of excellent alternatives are on the market. They are highly cost-effective and require less wood to cook. Therefore, you can transform an existing gas fireplace into a pellet stove. This will surely help you save costs and will perform better than gas models. It is essential to consider the low temperature of gasses that use for combustion.

Additionally, we should consider the massive amount of water in them. The liquid in the flue gas condenses inside the stack. The term stack refers to the cold surface inside the flue. Condensate begins to corrode and can hinder the operation of the smoke channels. This is why every oil boiler manufacturer recommends using pipes that are acid resistant (stainless steel or ceramic) for the stacks of furnaces.

Handling temperature fluctuation

Due to the massive fluctuations in temperature during winter, chimneys with structural integrity tend to be damaged. If a building is heated during winter, the massive temperature differential creates an entirely new situation. In this case, the liquid on the inside in the or stack pushed upwards on a more relaxed area. For stone and 120mm thick joints, this drying cycle can take between 3 and 6 months. This helps in the formation of bundling water in the stack. The cold winter night quickly cools the chimney following the closing in the heating process. However, in the stone, there are ice crystals that form also.

When the ice is formed, it expands in size, which, in turn, it creates internal limitations. Gas furnace vents are mainly utilized to heat homes. At night, these vents may also be covered in ice flakes. Because of the internal stress within a silicate block, the surface becomes affected. Cracking in the whole stone takes place in a thickness of around 120 millimeters. It is therefore advised to set the fireplace in the climate zone before the middle of September. This is the type of chimney that’s used for only structural vents. This means you can quickly determine the type of chimney, whether it’s structural or non-structural.

Heating and building blocks of chimneys

A fireplace is often referred to as the chimney breast. But the only dried woods that are advised to be used for the furnace. The moisture content shouldn’t go over 20 percent or more. The structural chimneys are constructed using silicate bricks as their internal construction. A stainless steel corrosion-resistant and acid-resistant pipe are attached to the conduit. The silicon pipe is applied to a mortar made of solid cement (T100 300). The chimney’s top is covered by a painted or galvanized cap made of metal. In this manner, the factors mentioned above will define your chimney’s structural character.

Reasons to reconstruct the chimneys

If you have a chimney, you may experience bizarre experiences. It is essential to know why this occurs. As well as the potential warnings and the repercussions. This will help you stay in peace and free from worry. Whatever the case, we’ll jump to the topic. Still, now we discuss how to tell if a chimney is structural. Now, let’s first look at the reason we should rebuild the chimneys. There are many reasons to rebuild or remodel the ducts that are structurally constructed. These are the reasons given below.

Soot formation

We discovered these abrasive spots typically in chimneys constructed of brick. Incorrect cleaning or fuel overloaded can cause this to happen. Additionally, improper operation of the furnace using closing the airside or residual moisturizing creates these spots. Clean your firebox Assembly as well as the flue frequently. This will keep your system clean from soot build-up.

Moorish chimney

If your chimney begins to tilt to one side, this could be a sign of trouble. In this case, it recommends that a professional in masonry contact to put it in the correct position. It is essential to resolve the issue quickly. If it is not resolved, it could referr to as a problem that is time to decide.

Chimney fire outbreak

If you’ve ever observed a tiny chimney fire, you should be concerned about it. There might be cracks or even debris in your chimney’s system. Perhaps it’s the result of a double-sided chimney issue. In these instances, it may be necessary to replace the whole vent. There could be a small flame inside the system. Although the fire isn’t large, it’s in the chimney. Therefore, the fire in chimneys can melt mortars and cause deep cracks in the bricks.

Water leakage

We may see drops of water forming in the vicinity of chimneys. Perhaps your chimney is damaged. Then, you see water leaking into your home through the chimney’s duct. If this issue isn’t resolved earlier, your whole chimney could break into pieces. Unfortunately, this will require a complete rebuild of the system. Therefore, it is better to look it up close and resolve the issue before it gets worse. This is one of the main reasons for rebuilding chimneys. Make sure you follow the suggestions we’ve talked about earlier. If you don’t, you could be faced with a replacement or reconstruction of your chimney.


It’s the last part of the discussion. Now you know how to tell if a chimney is structural or otherwise. We hope our clear instructions cover all the possible ways to identify a structural chimney. Here we try our best to explain everything about structural chimneys. We hope there is now something missing about this topic. If you think there is some information that we don’t cover here, you must let us know by commenting below.  

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