- Which brick to choose
- Selection and preparation of solution
- Apron base
- Masonry order
- Embroidery and decoration
Quite often, the unpresentable body of the iron sauna stove is covered with a screen, a particular example of which is the brick lining. Today we will talk about the materials used, the functional features of such a finish, as well as the rules for the construction of masonry and its decorative qualities..
Which brick to choose
Unlike a stone apron, a brick one causes less difficulties in construction due to the correct shape and standardization of the dimensions of the masonry elements. And yet, there are some features of the choice of material, because the cover has not only a decorative function.
First of all, any options for hollow bricks are excluded, and even more porous ceramics. The brick apron must have a high heat capacity, due to which smooth heating and slow cooling of the stove will be ensured. Therefore, to increase the inertia of the heating device, a material with a high density should be used..
Red refractory and fireclay bricks
Another aspect concerns the compliance of material properties with operating conditions. Not every building stone can boast of the ability to withstand high temperatures and changes in humidity. For these reasons, the use of silicate bricks is excluded, which, after several tens of heating and cooling cycles, simply turns into dust. The brick for the lining of the sauna stove must be ceramic, while the use of unburned second grade is not allowed.
Shaped clinker kiln brick
There is also an aesthetic side of the issue. The appearance of the heater is extremely important; it should not be discordant with the finish of the steam room, which is traditionally performed at the highest level. Since relatively little stone is needed for an apron, it will not be superfluous to carry out a piece selection, rejecting products with cracks, chipped edges, spots, and especially when the size and shape deviate from the standard. Also, for the sake of aesthetic requirements, you can replace ordinary ordinary ceramic bricks with clinker or refractory, torn or textured, use a combination of different types, achieving a unique appearance and pattern of the masonry, or perform the outer layer with a facing stone.
Selection and preparation of solution
We figured out the main masonry material, it remains to decide on the binder. Unfortunately, it will not be possible to use ordinary cement-sand mortar, despite the fact that we are not talking about laying the furnace itself and the furnace zone. However, the operating conditions of the apron are close to extreme, the outer and inner surfaces will be at different temperatures, therefore, to ensure the durability of the structure, an appropriate mixture must be used..
The first option is dry adhesive mixtures of factory production, which are used when laying stoves and fireplaces. Such a binder implies a minimum of problems during preparation and use, while there is a guarantee of maintaining the required qualities for a long time. However, such mixtures, also known as mortars, cost money, albeit relatively small. Before preparing the mixture, it is recommended to mix the dry mortar with M400 grade cement in an amount of 10-15% by weight; the binder can be cheaper by adding sand – up to a quarter of the total volume of dry components. It is better to mix the solution mechanically, after diluting the mixture with water to the consistency of thick sour cream and leaving it to brew for two hours.
Another type of binder is a lightweight clay-based mortar. The option captivates with its cheapness, but there are certain cooking rules. Dry clay must be well crushed and mixed with water for some time before use, depending on the quality of the raw material, it can take up to 2-3 days to swell. It is not difficult to make sure that the clay has collected enough moisture: squeeze a small lump in your hand, roll a dense ball out of it, which must be dropped on the floor from a height of 1–1.5 meters. Ideally, the sample should only flatten slightly from the impact, but not crumble or spread. When the clay is ready, it must be squeezed out of excess moisture and mixed with finely crushed fireclay in equal proportions by volume. It is quite permissible to replace up to half of the chamotte with washed sand, but cement or gypsum should be used with caution to accelerate the setting, their high content in a self-prepared mixture can lead to cracking of the joints.
The approximate required amount of the mixture is about 100-110 kg of dry powder per 1 m3 bricks. Thus, for each brick, about 200 g of a mixture of dry mortar with additives or about 350-400 g of ready-made home-made mortar will be consumed. Of course, a lot depends on the thickness of the joints, including the consistency: the thinner the layer of mortar, the less often it should be. If desired, the binder can be given a color, for example, blackened with shungite or clarified with chalk powder, as well as use universal dispersed dyes.
There are several types of heater placement in the steam room. A stove with a remote firebox always adjoins one wall, but can also be located in a corner. If the firebox is ordinary, the stove can be installed without being tied to the walls, but this is a rather rare case, typical for spacious steam rooms. In any case, the base sets the configuration of the apron, and it, in turn, is determined by the way the stove is placed and some functional features of the lining..
If the apron is arranged only for decoration and elimination of harsh heat radiation, it should adjoin the body of the metal oven almost closely. A gap of 20–30 mm is required to exclude direct heat transfer and to protect the masonry from thermal expansion of the metal housing. The base for such an apron has a minimum width, basically it is a tape of about 100 mm, which surrounds the heater around the perimeter from those sides where the protective screen is planned. For freestanding stoves, the base has the shape of a rectangle, for those attached to the wall, a U-shaped tape is arranged, for corner ones – an L-shaped one. Sometimes it makes sense to cover the stove even from those sides that face the walls, this will help avoid arranging a heat-resistant screen on the walls and make the decoration of the room more neat.
If the apron is arranged to increase the inertia of heating, the thickness of the masonry will be higher and the dimensions of the base should correspond to it. The massiveness of the brickwork is determined by the volume of the steam room. It is quite difficult to accurately calculate the required brick mass, therefore, an approximate ratio is used: 30-40 kg per 1 m3 the volume of the room, which is sufficient for the stove to evenly release the accumulated heat for at least an hour. It is imperative to take into account the mass of the stones, because clay bricks and most natural rocks have approximately comparable heat capacity. Having determined the required mass of bricks, you need to translate it into the number of stones and determine the number of layers of masonry. As a rule, in such cases, half or single masonry is used, very rarely the apron is laid out in one and a half bricks and almost never in two.
It is possible to increase the efficiency of heat transfer and the rate of heating the room by arranging a convection cover. In this version, a gap of up to 100 mm wide is formed between the masonry and the furnace body, while loopholes are formed in the lower and upper parts for free air circulation. All these factors determine the width by which the base tape should protrude beyond the dimensions of the stove in plan. Quite often, you can find the removal of the masonry above the base, which is acceptable from the point of view of aesthetics, but in this case, the protrusion of the extreme row should not be more than half the width of the stone. It is also advisable to pre-calculate the order of the masonry and adjust the size of the base in order to reduce the number of additional stones.
Let’s move on to the technical details. An ideal base for an apron is an extended or extended pedestal of the heater itself. If the apron is erected after the installation of the stove and completion of the finishing, additional difficulties may arise. The base must rest on the ground, therefore, it is necessary to remove some of the flooring and the supporting floor system around the oven. After removing the top layer of soil to a depth of 25–30 cm, backfilling with sand and gravel mixture in layers of 3–4 cm with intermediate compaction is carried out; it will not be superfluous to separate the backfill from the soil with a layer of geotextile. For the base to be stable, the pillow underneath should be as dense as possible. When the bed is prepared, the formwork is mounted according to the MZLF principle, then a concrete tape is cast, reinforced with one closed reinforcement belt, located in the upper load-bearing zone under a protective layer of 20-30 mm. If there is a desire to reduce heat leakage from the apron into the ground, foam polystyrene plates with a total thickness of 80–100 mm can be laid on the bottom of the formwork. The height of the tape usually does not exceed 15 cm, while it is important to bring the upper edge into the common plane, using the sides of the formwork as beacons.
The apron must be protected from capillary suction of moisture, for which several layers of roofing material or one layer of high-quality deaf waterproofing are laid on the concrete base. The first row is laid on top of the hydro-barrier, which sets the general laying order and determines the geometry of the apron. It is advisable not to use extensions in the first row, however, if this cannot be avoided at all, then it is better not to place the cut bricks on the outer corners, ensuring the correct dressing between the rows in the future. Additionally, we note that the bottom row is laid on an increased layer of thick solution, due to which possible curvatures of the base are leveled.
The apron is laid with a dressing between the rows at half the length of the stone. Each new row should be started from the corners, placing the starting stones on a plumb line and maintaining the perpendicularity of the converging planes. When installing a convection apron, the lower loopholes are formed in the second, and even better – in the third row, while gaps are made every 2-3 bricks. Each stone must be soaked in water for 10-15 minutes before laying, so that hygroscopic ceramics do not pull moisture out of the solution too intensively. The total height of the screen is about 120-140 cm, that is, about 15-17 rows, of which from 6 to 8 are laid out on the first day, the rest – on the next.
Care should be taken when laying the top 4–5 rows. If we are talking about a convection cover, holes should be formed in the upper zone, while it is desirable that the two final rows are solid. It will also not be superfluous to strengthen the final rows of masonry with reinforcement, for which you can use galvanized wire or strips of plaster steel mesh. The top row of bricks must be laid on the bed in such a way as to block the space between the oven and the masonry, leaving a gap from the body of at least 2 cm to maintain convection and eliminate pressure on the masonry of the body expanding when heated. Traditionally, the top row of the apron forms the side that supports the main laying of stones in the steam generator.
Embroidery and decoration
When the oven is lined with bricks, you must wait at least a week for the mortar to set normally. During this time, even at room temperature, the bulk of moisture will come out of the seams, it is only important to prevent hypothermia below 10 ° C. Next, the masonry must be thoroughly dried, maintaining a weak burning of the furnace for several hours, while the masonry must warm up to 50-60 ° C, it is advisable to repeat the procedure several times within 2-3 days in a row. After that, you should arrange some semblance of burning, melting the furnace to the maximum temperature and maintaining this combustion mode for 4-5 hours.
There are several ways to improve the appearance of brickwork. If a smooth brick was used, the seams are embroidered, deepening them by 2-3 mm, you can also fill the joint flush, and then grind the common plane. For torn bricks, it is preferable that the groove of the seams is approximately equal to their thickness. If the solution was not colored in the mass, you can emphasize the jointing with ordinary water-based paint..