Features of Chimney Construction

Features of Chimney Construction

In modern construction, systemic chimneys are increasingly used, but brick chimneys continue to retain their relevance. At the same time, it is extremely important to properly select materials for their construction so that the chimney is reliable and properly performs its functions. For brick chimneys, solid or hollow bricks are usually used.

The chimney is one of the most significant elements of a building, and its repair or reconstruction is extremely labor-intensive and costly. For this reason, one should not overly economize during the construction of a chimney.

To construct a brick chimney, it is necessary to thoroughly study the characteristics of the ordered materials, in this case, the bricks.

It is important to use high-quality stove bricks. They should not contain a large amount of marl and should have a smooth surface. That is why it is preferable to choose products from proven manufacturers, as some of them save on components, so only purchase the highest quality materials. Most modern manufacturers use ceramic hollow bricks as the main material.

Clinker brick has excellent properties for the efficient and durable operation of chimneys. However, this is a very expensive material, several times more expensive than solid brick.

Construction Stages

The erection of a brick chimney requires compliance with certain stages and technologies. First, the foundation on which the chimney will be located must be carefully prepared. It must be strong and resistant to loads and deformations. An armored concrete slab is laid under the foundation.

Next is the stage of bricklaying the walls. It is important to use quality mortar and observe the bonding of bricks to ensure the strength and tightness of the structure. It is necessary to consider the requirements for thickening the walls of the chimney in the upper part to increase their resistance to wind and temperature loads.

As masonry progresses, dividing walls between the chimney channels are installed. To prevent the masonry from settling on these walls, metal ties are provided.

The final stage is arranging the chimney exit above the roof of the building and waterproofing the passage through the roof. For facing the upper part, frost-resistant clinker or solid ceramic brick is recommended. Special caps and deflectors are installed to protect against precipitation.

Using Clinker and Hollow Brick

Clinker bricks are often used to face the upper part of the chimney protruding above the roof of the building. They possess the necessary properties and ensure the prolonged service life of the chimney, subjected to direct atmospheric factors.

Unfortunately, hollow brick is often used in chimney construction. This is a serious mistake, mainly due to the ignorance of the customer, especially when concluding a contract with a contractor for material supply (hollow brick is often slightly cheaper than quality solid brick).

The chimney must be made of solid brick of full length (height). It is especially dangerous to construct the upper part of the chimney above the roof from hollow brick. From the outside, it may look the same as ordinary brick, and many customers are not even aware of the material from which their chimney is constructed.

Using hollow brick for chimney construction can lead to serious problems and poses a threat to the overall integrity and safety of the structure. Chimneys are subject to significant temperature loads and the influence of aggressive smoke components, so the materials from which they are made must have high density and strength.

Hollow brick has cavities inside, which reduce its compressive strength and resistance to high temperatures. Over time, under the influence of heating and cooling, these cavities can collapse, leading to the cracking of the brick and the formation of through holes in the walls of the chimney.

Through holes and cracks in the chimney walls create a risk of penetration of combustion products, including carbon monoxide, inside the building, posing a serious threat to the health and life of people. In addition, moisture can penetrate through these holes, which, when freezing, will destroy the brick masonry from the inside.

Using hollow brick is especially critical in the upper part of the chimney above the roof. This area is most exposed to wind, precipitation, and temperature fluctuations. The cavities in the brick contribute to the rapid penetration of moisture inside the structure, leading to its destruction and leaks in the roof.

Therefore, the use of hollow brick for chimney construction is unacceptable, as it jeopardizes the safety of the entire structure and the building as a whole. Only high-quality solid brick, capable of withstanding high temperatures and the aggressive environment of combustion products, should be used for chimney construction.

Safety Requirements

When constructing chimneys, it is necessary to strictly adhere to fire safety requirements. In particular, the distances from the chimney walls to wooden structures must be at least 50 cm. Non-combustible insulation, such as mineral wool, is used for thermal insulation.

It is important to ensure the mechanical strength of the chimney, its ability to withstand high temperatures and the impact of aggressive environments. This is achieved by using quality materials, including refractory ones, and proper masonry complying with the norms.

To ensure the safe operation of the chimney, it is necessary to provide a ventilation system in accordance with the project, calculated for the extraction of combustion products. Fire shutters and sediment chambers are also installed for collecting condensate.

Modern Alternatives

In addition to traditional brick chimneys, other solutions are currently being applied. These are stainless steel modular systems, easy to install. They have good corrosion resistance and withstand high temperatures. However, metal is prone to deformation due to temperature fluctuations.

Another modern option is ceramic modular chimneys made of dense heat-resistant brick. They are easy to install, reliable, and durable. Some manufacturers offer chimneys made of high-strength insulated concrete.

The choice of one solution or another depends on the building's design, operating conditions of the chimney, budget, and other factors. The advantages of modular systems are ease of assembly and maintenance. Brick chimneys are more massive, sturdy, and durable.

Care and Maintenance

To ensure a prolonged service life and safe operation of the chimney, it is necessary to regularly service and maintain it. At least once a year, it is recommended to call specialists for inspection and cleaning of the flue channels from accumulated soot and other deposits.

It is important to promptly remove sediment and condensate from sediment chambers. Otherwise, stagnant moisture will destroy the internal walls of the chimney.

At least once every few years, a full inspection of the chimney should be carried out, including measuring the thickness of the walls, checking the integrity of the insulation, detecting cracks, and potential leaks.

Special attention is paid to the state of the upper part of the chimney above the roof. The tightness of the passage through the roof, the absence of masonry damage, and waterproofing are checked. Timely repair and replacement of damaged elements are carried out.

Adherence to regular preventive maintenance significantly extends the service life of the flue and avoids serious damage to the structure and building as a whole.

Frequently Asked Questions (FAQ)

Q: Can silicate brick be used for chimney construction?

A: Silicate brick is not recommended for chimney masonry, as it does not have sufficient fire resistance and strength. When heated, silicate brick can lose its properties and disintegrate. It is better to prefer ceramic or refractory types of bricks.

Q: What is the optimal thickness of the walls of a brick chimney?

A: The thickness of the walls should be at least 120 mm (for solid brick). In the upper part of the chimney above the roof, thickening of the walls to 250-380 mm is recommended to increase their resistance.

Q: Is it necessary to make dividing walls in the chimney?

A: Yes, dividing walls are an important element of the structure of a multi-channel chimney. They prevent the mixing of smoke flows from different channels and the spread of possible ignition.

Q: What materials are suitable for waterproofing the place of passage of the chimney through the roof?

A: For waterproofing, special rubber gaskets, mastics, waterproofing compounds on a cement or bitumen basis are usually used. It is important to ensure tightness to prevent leaks.

Q: How often should the chimney be cleaned of soot?

A: It is recommended to clean the chimney at least once a year before the start of the heating season. For chimneys from stoves operating on coal or wood, more frequent cleaning may be required.