Having decided to build a brick chimney with your own hands, you will follow the path of the nameless masters who laid stoves one and a half, and two hundred years ago.
Therefore, you should not “reinvent the wheel” if you can use their experience.
How to make a chimney according to all the rules will be discussed further in our new article.
Advantages and disadvantages of a brick chimney
Despite the fact that the metal pipe is no longer exotic, chimneys continue to be made of brick. In some ways, this looks like an anachronism, but there are good reasons why you should not abandon the classic technology of laying smoke ducts.
The main one — brick has a high thermal inertia. Exhaust hot gases heat it weakly, which significantly reduces the fire hazard of the heating device. We must not forget about another aspect — the temperature of the smoke at the upper cut of the pipe should not fall below 60–70 degrees. Otherwise, condensation will flow through it. The brick plays the role of a thermos shell and does not allow the smoke to cool too much.
But there are two fatal flaws:
- The complexity of the masonry.
- The weight.
On the pipe with all the elements, depending on the height of the attic, it takes from 400 to 800 pieces of bricks weighing 3.8 kilograms.
A column having a base area of not more than 0.25 sq. meters, the whole mass presses on the stove. This is a concentrated load. If the total height of the pipe exceeds 5 meters, then it is placed on a separate base, and connected to the heater with a transition pipe.
Brick chimney as an engineering structure
The chimney, for all its external unpretentiousness, is a complex engineering structure, to which serious requirements are imposed. They relate to strength, fire safety, the ability to effectively remove hot gases. Therefore, the installation of a chimney in a wooden house should begin with an acquaintance with its device.
- Internal chimney — is conducted from the ceiling of the furnace to a level below the ceiling by four rows of brickwork.
- Cutting (fluff) — expansion of the wall thickness of the pipe when it passes through the ceiling.
- External chimney — conducted through the attic to the level of the roof.
- Otter — another expansion of the thickness of the walls of the chimney, arranged to cover the gap between it, the roof sheathing and its covering.
- Neck — continuation of the external chimney.
- headroom — thickening of the walls, which plays the role of a deflector.
Requirements for a brick chimney
The main one is the distance “from smoke” to combustible structures. It is equal to 250 mm — this is the full length of a solid ceramic brick.
The second requirement is the strict verticality of the structure. Deviation from it by more than 3 degrees (per one meter of height) is not allowed. Also, there should be no through cracks in the brickwork.
The main criterion is the internal section. The ability to remove hot gases mainly depends on it. The more powerful the stove, the wider the chimney should be. There are three standard sizes used for one or another type of heating device.
- “Four” — a row of which is formed by four bricks. Section 125 by 125 mm. It is used for cooking stoves or heating stoves of low power.
- “Five” — a rectangular chimney, formed by a row of five bricks. Section 250 by 125 mm. It is used for heating and heating-cooking furnaces. Chimneys for fireplaces smaller than this section are not recommended.
- “Six” — a square pipe, a row of six bricks. Section 250 by 250 mm. It is used for fireplaces and European stoves — wherever a minimum resistance to the movement of hot gases is required.
The second most important criterion in the calculation is height. It depends on the place of its output to the roof relative to the ridge:
- Pipes installed on a ridge or at a distance of no more than 1.5 meters from it rise 0.5 meters above the roof.
- Chimneys passing through the roof at a distance of one and a half to three meters to the ridge are made with a height equal to it.
- If the distance is more than three meters, then the angle between the ridge and the upper cut of the pipe should be 10 degrees.
There is no fundamental difference between the laying of an array of stoves and chimneys. It is carried out on a clay-sand mortar using the same tools — an oven hammer, a trowel and a plumb line. However, elements such as fluff and otter are laid out using a large number of pieces of brick 1/8, 1/4, 1/2 and 3/4 of the whole.
To avoid splitting and teska, which are accompanied by clouds of brick dust and rarely give the desired result, it is worth using a “grinder” with a diamond wheel for ceramics. This guarantees the accuracy of work, eliminates tedious work and a lot of useless brick battle.
For masonry up to the roof level, a mixture of sand and clay is used, since it has a coefficient of linear expansion similar to brick, which is a certain guarantee against the appearance of cracks.
The pure clay used as a binder can be either oily or lean. In some places, deposits come across where the proportional ratio of the amount of clay to sand is naturally optimal: one to three or four.
With an increase in the volume fraction of clay, the solution cracks after drying, and with a decrease, it crumbles. To determine the optimal ratio of volumetric parts, it is necessary to knead the finished solution in the fingers. It should not be noticeably slippery or rough, like sandpaper.
The excavated clay is soaked in an iron container for 3–4 days. The result should be a homogeneous clay pulp without stones, similar in consistency to liquid sour cream.
The sand taken in the floodplain of streams and rivers is very fine, dusty. It is not suitable for laying. It is better to use one that consists of grains of 0.8–1 mm. It is rough to the touch.
Clay and sand are mixed by volume in a ratio of one to three or four. Water is added gradually, in small portions. The finished solution should leave traces on the trowel (but not stick to it) and not drain from it.
To avoid errors in proportions, it is better to buy ready-made dry clay-sand masonry mixture. Please note that the one marked “refractory” is not suitable for masonry.
Solid burnt red brick is used.
Its edges should be even, without cracks, and the sound made by a light blow on it with an oven hammer should be sonorous.
The standard size used for masonry is 250 long, 125 wide and 75 mm high.
Internal chimney masonry
It begins immediately after the damper is installed and the furnace overlap is completed. The masonry techniques are the same — applying a layer of mortar, laying bricks, “shaking” it with your hand and lightly tapping it with a pick. Verticality and horizontality are checked after laying each row. Finish it for four brick heights to the ceiling.
The expansion of the chimney wall thickness is carried out to comply with the requirement that combustible structures be located at a distance of 250 mm “from smoke”. The usual wall thickness of the chimney is 125 mm. To double it, you need to fold four rows, each of which moves outward by 1/8 of the width of the brick relative to the bottom — just the amount that allows the brick to lie without being thrown over. The masonry principle for all three sizes is the same:
- The inner surface (to the smoke) of the first row is laid out in 1/8 parts. The gaps between the outer bricks are filled in 1/4 increments.
- In the second row, the parts increase, respectively, to 1/4 and 1/2.
- On the third row, 1/2 and 3/4 parts are used.
- The outer belt of the fourth row of fluff is laid out with whole bricks.
Having reached the ceiling, it is laid, observing the dressing of the seams, two or three more rows higher. A gap of 2–3 cm is left between the ceiling and it, in order to exclude the pressure of the structure on the masonry. It is covered with mineral wool boards. Laying up to the roof is carried out in the usual manner — with dressing of vertical joints and control of verticality.
It begins after the edge of the chimney brick has risen above the roof. It is carried out outside, in compliance with all safety measures when working at height. You can use cement mortar. They start it from the edge that is lower along the slope. The distance from the smoke on each row is equal to 1/8 of the width of the brick. In total, the otter should have six rows. After it, they put the neck — the usual continuation of the chimney. The gaps between the roof and the chimney are closed with a “collar” made of sheet roofing steel.
This is a chimney deflector that prevents smoke from clogging into the chimney during air turbulence.
It is laid out in two rows, shifting the first from the smoke by 1/8 of the brick, and the second by 1/2.
For its protrusions, you can hook the clamps of a metal cap, which prevents precipitation from entering the pipe.
How much will it cost
The brick chimney on the roof has managed to become a visual constant in three centuries. And a building with such a finish looks, according to subjective estimates, much more attractive.
It remains only to determine how much it will cost you to comply with the canons. If you involve third-party craftsmen, then the price of the work will be added to the cost of the brick. And she’s big. In the world and the region, for example, laying one brick will cost from 50 to 90 rubles.
The solution, if you prepare yourself, is free.
Five kilograms of the finished masonry mixture cost 60–70 rubles. One package is enough for 10–15 rows of pipes with a section of 125 by 250 mm (six).
Let’s compare the cost of a meter of a metal sandwich pipe with a diameter of 250 mm and a brick pipe with a cross section of 250 by 250 mm. Just the kind that can be used for installing fireplace chimneys.
|Brick (at a price of 15 rubles apiece)
|metal sandwich pipe
As you can see, the prices are almost the same. Of course, it is worth adding the price of masonry fluff, otter and head. But, given the best performance characteristics of brick pipes — no corrosion, high thermal resistance, it makes sense to spend money on such an acquisition. And if you are going to lay a brick chimney with your own hands, then it will cost almost half the price of metal sandwich pipes.
Secrets of the skill of stove-makers
- Before laying, the brick must be soaked — lowered into water and wait until the violent eruption of air bubbles stops. Wet ceramic blocks adhere more strongly to the mortar.
- For splitting and tesky bricks, use a “grinder” with a diamond disc for stone.
- When laying in the attic, hang a plumb line on the rafters, between the future pipe and the workplace. This will save you from having to touch it to check. To control the verticality of the angle, it is enough to change the position of the head.
Do not forget that a chimney in a private house is not only a convenience, but also a technical device that requires proper operation and maintenance. Clean it of soot, inspect it for cracks, heat the stove or fireplace with dry wood and it will serve you well for many years.