Brick laying at low temperatures. Winter brickwork: technology, recommendations.
Winter time is not considered the best period for construction work. But there are situations when the conservation of the construction site can lead to significant damage. In winter, it is most difficult to carry out bricklaying, however, even this task is quite feasible.
Brick laying in winter should be subject to certain rules, due to which construction work can be carried out in its entirety even at temperatures up to -50 ° C.
In this case, there is no need to isolate the steam in the room. Residential building, walls - concrete blocks 300 mm, outside - siding. The living spaces are cold, too much energy is spent on heating. Objective: to place insulating materials inside the building; The inner lining is made of drywall with subsequent wallpaper. Without polyethylene foam, such a value of heat transfer resistance provides one layer of polystyrene or mineral wool with a thickness of about 60 mm, and steam insulation in this case is mandatory.
The same regulatory requirements correspond to 5 mm polyethylene foam. Polyethylene foam performs the functions of thermal insulation and vapor barrier. The air cavity between drywall and polyethylene foam should be 20 mm. If we use foil foil wrapped in aluminum foil unilaterally, the foil should be rotated inside the room. If the building does not work constantly in the winter and from time to time, the thickness of the polyethylene foam can be reduced.
Problems of bricklaying in the winter
When laying brick in cold weather, it is most difficult to provide the building with the required strength. When the air temperature is below zero, the water contained in the fixing solution freezes, thereby terminating the necessary process of cement hydration. If the water does not have time to turn into ice, but at the same time it gets from the cold to the warm, this will lead to the surface of the bricks being covered with ice. After some time, the ice located both inside the masonry and on the surface of the bricks will melt, but the adhesion of the solution will decrease significantly. After complete thawing, the strength of the masonry will decrease by about a quarter from the required standards. In addition, when the water in the solution turns into ice and then thaws, free spaces form in the masonry, due to which the structure may collapse after some time.
The villa has a covered terrace. The house is sometimes used in winter and has a terrace only in summer and between seasons. The annex to the building is skeletal. Therefore, there is no need for thermal insulation. This is necessary to prevent skeletal walls can be blown up by cold winds and completely eliminate the possibility of condensation, even if the winter was in this room, to be well warmed up. When applying massive thermal insulation, additional materials are required that need to be installed - in order to make vapor insulation inside and protect from external winds.
How to prepare a mortar for bricklaying
Despite the existing disadvantages, brick laying in frosts can be no less durable than in the warm season. However, this requires a special solution.
Antifreeze additives should be included in the mortar for masonry bricks, which will ensure a decrease in temperature. It is recommended to use a brand of at least 50, where the necessary additives are already included. The most important thing is to follow the process of solidification of the solution. To do this, small nests with plugs are made in the masonry, so that you can measure the temperature both inside and outside with a thermometer.
When installing polyethylene foam as the main insulation, the need for additional materials is completely eliminated. Foamed polyethylene is used with a thickness of 3 to 5 mm - one or two layers, depending on when the owner of the cottage discovers the season. In all foil and polyethylene applications, the joints must be covered with aluminum adhesive tape. First of all, we need to understand what kind of room it is and what the temperature regime is. The most difficult option is when the balcony is connected to the living area of \u200b\u200bthe apartment.
In this situation, we must make the insulation in accordance with the regulatory requirements that apply to residential premises. Only in this case we can talk about comfortable operating conditions on the obtained area and make sure that there will be no problems with cold or wet walls. It is also necessary for vapor barrier. This is why people often refuse to rebuild balconies. Just use polyethylene foam - this eliminates the need for vapor barrier. The apartment is cold, the walls on the street are very cold, some corner walls are even wet.
Bricklaying in winter conditions
The masonry optimal for winter time can be made by artificial heating or by freezing. In some cases, at very low temperatures, additional heaters must be installed above the masonry itself.
These are the most common examples of our time. Moisture is formed on insufficiently insulated walls. Simple thermal insulation often does not help. When using materials that penetrate through water, such as polystyrene foam, moisture may disappear on the wallpaper. But it will continue to form in the form of condensate on a cold surface - between the supporting wall and the foam. Practice shows that this problem is completely solved by laying only a thin one-sided foil foil with polyethylene 3 mm thick.
It also serves as thermal insulation and vapor barrier. Using polyethylene foam, we do not hide moisture, but simply create conditions that it does not condense. On this topic we will answer another frequently asked question: do not stick to polyethylene wallpaper! Since the thermal insulation values \u200b\u200bof each material depend on its density - the lower it is, the better the properties of the properties. And to use the material for wallpaper, it must be solid.
Winter mortar for bricklaying
Getting to work, you need to consider that all antifreeze additives are toxic to humans. You can work with them only in overalls, goggles and tight gloves.
For the same reason, any mixtures containing chemical additives are allowed to be used only for the construction of retaining walls and foundations. Bricklaying in winter conditions using chemical mixtures is strictly prohibited for the construction of residential premises.
On heat-insulating wallpaper do not stick. In the case of polyethylene, the following arrangement follows: it is laid on the wall, then 20 mm thick sheathing is applied, and then any facing materials such as a pillow, upholstery, drywall can be installed. But if you can’t make repairs, what should I do? First of all, understand that important steps have already been taken - the gaskets are inserted into the windows. Insufficient heat-insulated walls and, consequently, excessive heat loss, room temperature and radiator power are all elements of the same chain.
Methods of laying brick in the winter
Laying in negative weather is most often carried out in the following ways:
- Electric heating
Since this method is quite time-consuming and energy-intensive, it is recommended to use it only for the construction of small sections of walls. During the masonry of the walls, electrodes are placed horizontally in the finished solution, through which electricity will later be passed. When heated, the electrodes will also heat the joints of the masonry, which, accordingly, will eliminate the formation of ice. However, for efficient electric heating, it is extremely important that the seams are completely filled.
To increase the temperature, you must either insulate the walls or increase the efficiency of the radiators. For this purpose, a single-sided foil foil is used from foil foil with a thickness of 3 to 5 mm. The material sticks to the wall behind the radiator, so it is not visible from the side. Theoretical estimates show, and practice has repeatedly confirmed that thermal radiant heat is increased by 20%. In other words, for a simple 5 kW radiator, the effect will be the same if we put a 1 kW power radiator next to it.
Brick laying in negative weather
- Erection of a greenhouse
This method is very effective, but rather laborious. Its essence lies in the fact that around the future wall or part of the wall, a frame of rails is installed. The frame is covered with plastic wrap or similar materials. In order to provide heat to the future construction and masonry mortar, any heat source must be installed inside the frame, for example, a stove, generator, electric heater, etc.
For those who have well-heated homes outside the city, this effect means a lot. Just radiators stop heating the wall under the window, and the heating system consumes less energy, keeping the room temperature the same. This saves gas or electricity. Thermal insulation is a system in which a thermal insulation layer of building materials is applied outside or inside walls. This reduces energy loss and increases comfort in the home.
Old windows, walls, ceilings and floors are weak places where most of the heat is lost in the house without insulation. The greatest losses are through uninsulated walls. In accordance with the Law on Energy Efficiency, if citizens improve their home with a major overhaul and insulation, they will be exempted from the construction tax for ten years. However, this applies only to buildings with perfect thermal insulation.
In order for the winter masonry of the brick to be erected in accordance with all the required standards, it is necessary to heat the heat for several days. Since it is practically impossible to erect a frame teak over an entire house or at least over one wall, this method is suitable exclusively for the construction of individual elements.
But thermal insulation has other advantages, as well as the simultaneous solution of several problems. Housing heating costs are reduced, the return on investment is from 2 to 3 heating seasons; The walls absorb and retain a significant amount of heat, acting as a heat accumulator and contributing to greater thermal stability - maintaining temperature with minimal room fluctuations. The temperature in the home remains relatively stable - 6-8 degrees higher than outside, and without the use of heaters; Prevention of mold on the walls of the home; External thermal insulation also has an additional soundproofing effect; External insulation extends the life of the building by slowing down the aging process and corrosion. An energy-efficient building should be built in accordance with the idea of \u200b\u200benergy saving - very good external insulation, energy-saving windows and household appliances.
Cladding brick laying in winter
- Freezing method
Cladding brickwork in winter is most effective if the work is done according to the method of freezing. The essence of the freezing method is based on the fact that a special cement mortar for winter bricklaying can set again some time after thawing.
When building an energy-efficient home, you need to not only look at the prospects for reducing heating costs, but also in terms of improving the quality of life. However, adequate insulation can save up to 50% of these costs. In addition to the thickness of the insulation, the owner must also consider safety, comfort and, most importantly, durability.
The external insulation of the facade allows the wall's ability to accumulate heat and radiate it back to the room. Thus, the energy efficiency of the building is achieved, since the stored heat in the room lasts much longer. In order for thermal insulation to have a positive effect and increase the ratio of the heating coefficient to capital, it should be applied using special technology and skilled workers.
For masonry according to the method of freezing, you can use only a heated solution and a brick completely cleaned from freezing. If the ice on the bricks has already formed, it is more convenient to remove it with an injection burner. In addition, for this method it is recommended to use the highest grade of solution.
Where should the insulation be installed ?! Insulation should be placed where the house loses heat and where condensation forms - as a rule, these are external walls. The only correct place of isolation is located next to the coldest place - outside. Thus, the temperature gradually rises from the outside inward, and the inner surface of the wall has a temperature close to air temperature.
However, in order for the insulation of the room to be fully effective, it is recommended to make the internal insulation with a thinner material - for example, a lifton, cork boards, insulating wallpaper, etc. this provides faster warming of the room and lower losses With accidental heating. Internal insulation can be placed anywhere and has the advantage of being easier and cheaper to place. However, disadvantages are more than advantages - apart from the volume of the room, the condensation problem has not been solved.
Is it possible to lay a brick in winter
The solution has the ability to cool quickly, because of which ice is formed in it. Therefore, it needs to be heated up for a maximum of half an hour. To avoid freezing, the solution must be diluted in small portions.
Also, the answer to the question - is it possible to lay a brick in the winter, depends on the quality of the work. During winter masonry, it is necessary to carefully monitor the fullness of the seams, especially vertical ones.
Condensation simply moves behind - between the insulation and the wall. However, in order for the house to be effectively insulated, individual elements should be well evaluated - walls, ceilings, floors and windows. Internal insulation has two big advantages: it is easier and cheaper.
However, its disadvantages are more than advantages. However, the insulation sometimes rotates - in buildings that are cultural monuments and are protected, as well as where the facade and the characteristic layout of the building should not change. Another plus is that the walls are laid out from the inside, which has easy access. Work can be performed sequentially in the room and separately and can be performed by the developer if he knows about this technology.
Final work
After the erection of a brick wall to a level not higher than one floor, it is necessary to install prefabricated ceilings. If the masonry is carried out by freezing, the height of the erected structure in winter should not exceed 15m.
Internal insulation, the temperature of the inner surfaces of the walls increases, because they were obtained by lining the insulating layer. This helps the rooms warm up faster, but they also expire faster. Internal insulation has the following disadvantages.
The dimensions of the premises are reduced, it is necessary to replace window sills, cornices and other elements attached to the wall, and to prevent the accumulation of heat from the building structure, the walls remain cold - the heat is reflected by them and remains in the room; There is a so-called accumulation of heat from the walls, and therefore the rooms are warm, but they also cool quickly; Connections of panel units are not sealed and moisture penetration is prevented; Due to the nature of the materials of which the insulation boards are made and the fact that they are relatively soft, mechanical deformation on their surface is possible, as a result of which the plaster falls off the walls. Mineral wool rolls, cut into wooden or metal mesh, being the main material for the implementation of internal insulation in maintaining and forming a coating of hardboard or gypsum.
In addition, it is extremely important to monitor the masonry with the advent of the thaw. In order to provide additional stability and strength of the brickwork in the spring, it is necessary that the distance between it and the transverse walls does not exceed 20 m. In addition to all of the above, the walls on the south side must be hung with a glassine or moistened.
Winter conditions for the erection of stone structures are considered to be those in which the average daily outdoor temperature is below + 5 ° C and the minimum daily temperature drops below O ° C.
To obtain a masonry of a given design strength, various technology groups are used:
• freezing on ordinary solutions with a limitation of the height of the structure;
• freezing with temporary strengthening of the structures of the underlying floors for the period of laying with the masonry of the rated strength;
• freezing the masonry of the overlying floors with artificial heating of the structures of the underlying floors until they reach the rated bearing capacity;
• artificial heating or heating of individual structures with heated air or electricity;
• in greenhouses;
• on solutions with antifrosty additives.
Regardless of the technology adopted, the following activities are carried out:
Masonry is carried out on a heated solution; at the time of spreading the solution on the wall, its temperature is the reciprocal of the ambient temperature. To do this, during cooking, water and sand are heated to 60-90 “C;
- solution delivery in dump trucks with closed bodies; double bottom body, exhaust heating;
- the solution is supplied to the workplace in the amount necessary for 20-30 minutes of work.
Freezing methods are suitable for structures erected from stones of the correct form (bricks, ceramic, concrete, cinderblock and natural stones, large blocks, as well as bedding butts), and are not allowed for structures that are subject to dynamic effects during thawing or erected in seismic areas; for thin-walled arches, cornices with a span of more than 200 mm and ordinary lintels with a span of more than 1.5 m.
For masonry using the freezing method, plastic, workable cement and complex mortars with a mobility of OK - 9 ... 13 cm are used for structures made of solid brick and concrete stones; OK -1 ... 8 cm - from perforated bricks and hollow stones; and OK - 4 ... 6 cm - made of rubble stone.
Masonry technology "for freezing". The base is cleared of snow and ice. Masonry is carried out in the usual way. Soon after laying, the mortar, having gained some strength, freezes, which provides additional strength to the masonry. At the onset of warm time, the solution gradually thaws, while at the same time gaining strength. At the same time, the final strength decreases, so initially the grade of the solution increases by 1-2 steps, which is set by the project. In addition, corners and wall junctions are reinforced; openings increase in height by 20-30 mm (for settlement of masonry after thawing). The total height of the walls is limited to 15 m (4-5 floors).
The most responsible for this method is the thawing period. The following activities are carried out here:
It is necessary to ensure the gradual thawing, so that the thawing speed does not exceed the speed of curing. To do this, with a friendly sunny spring, it is necessary to close all piers with a light screen from overheating in direct sunlight. Otherwise, emergency deformations can occur, which often lead to collapse of structures;
- heavily loaded areas of masonry should be unloaded. Usually these are places where the balconies are supported; under the balconies put temporary supports on all floors (Fig. 7.24);
- twice during the shift, the masonry settlement is monitored, the cracks that have appeared are fixed, their dynamics is controlled by beacons;
- a logbook of works on the "winter" masonry.
Heated air heating. In order to protect the frozen masonry from precipitation in the spring and increase its bearing capacity, simultaneously with the construction of the upper floors, internal heating and drying of the rooms of the lower floors is organized with air heated by oil and gas heaters. For the first three to five days, maintain a temperature of 30-35 ° C, then lower the temperature up to 20-25 ° C. After connecting the central heating, the heaters are removed. On the dried floors, they begin decorating.
Masonry with chemical additives. During preparation, additives are added to the solution that reduce the freezing temperature of the solution and accelerate the hardening process. To complete freezing, the solution gains 40-50% of the design strength. As additives, use: CaCl2 — calcium chloride (HC), NaCl — sodium chloride (CH), K2C03 — potash (P), NaN03 — sodium nitrite (HC), and others in an amount of 2-3% by weight of cement.
Solutions with the addition of sodium nitrite gain strength at an outdoor temperature of minus 15 ° C, with the addition of potash, hardening to a temperature of minus 25 ... 30 ° C, with the addition of calcium chloride - up to minus 35-40 ° C.
The method is simple and reliable, however, it should be remembered that after 3-5 days white streaks appear on the wall - efflorescences that will be washed away from the facade by rains only after 6-12 months.
Masonry with heating. During electric heating, rods with a diameter of 6-8 mm are laid in the joints of the masonry, through which the solution is heated (similar to concrete).
In this case, the solution in the joints should be unfrozen. The masonry is heated with single and group electrodes (individual rods or grids of reinforcing steel with a diameter of 4 ... 6 mm), laid in horizontal seams of masonry, which are connected to different phases of alternating current with a voltage of 220-380 V. Structures are heated at a temperature of 30-35 ° C until the solution acquires a 20% design strength.
With one-sided heating from the room after the walls are laid and the ceilings are laid, heat is supplied to the rooms: they start the apartment heating system; set heaters; lead heating by infrared burners. From this internal (room) heat, the wall gradually warms up and the solution in the masonry gains design strength.
Masonry in "greenhouses". It is used for small volumes and tight deadlines. Above the future design, a spatial fence is erected - a tent ("teplyak"). Under it, warm air is supplied by a heater or heating devices are placed inside the tent. Laying is carried out in the usual "summer" way.
A source: Technology of construction processes. Snarsky V.I.