Aerated concrete is a synthetically created building material. It is made as a result of temperature exposure on all components. The main advantages of this material are ease of production, light weight, strength, and thermal insulation. However, despite all its advantages, many unskilled workers do not like to work with it. But professionals are happy to use aerated concrete blocks. There are some features of laying such blocks.
Selecting Tools
In order for the laying of aerated concrete to be correct and durable, it is impossible to do without the use of special tools. To prepare a concrete solution you will need an industrial mixer and a mixing container. In order to apply the mixture, you will need several trowels different sizes. To fit aerated concrete blocks together, use a special hammer and a measuring level. If you plan to process an aerated concrete block, then it would be a good idea to stock up on tools such as a marking ruler, a file, grout, equipment for forming grooves, drill attachments, a drill, and a brush.
Masonry methods
Preparation of mortar for masonry. Today, there are two methods of laying aerated concrete products with your own hands, this is laying aerated concrete blocks on cement mortar and onto the adhesive mixture. But, despite the chosen installation method, the first row must be laid on cement mortar. The dosage of the components should be such that the resulting masonry mixture does not spread, because otherwise the block will not be fixable. If the construction is large, then it is much more convenient to mix the solution not with your own hands, but with the help of a concrete mixer.
Glue solution
To ensure that the resulting solution has a uniform texture, it is better to use equipment operating at low speeds for mixing. To mix glue from five kilograms of dry mixture, a liter of water is poured into the vessel. Dry glue is slowly poured into the vessel and immediately whisked. Let it sit for ten minutes, and then beat thoroughly again. The adhesive solution can be considered ready when it becomes similar in consistency to thick sour cream. If the glue has dried and hardened, it must not be diluted with a new mixture or water.
Cement-sand mixture
A similar solution can be used to lay in blocks. It is made by mixing all the ingredients and a special binder. Such compositions are easy to prepare and reliable to use.
The recipe for such mixtures may vary slightly, depending on the required task. If it is necessary to obtain a more plastic mixture, then clay is added to the composition. This mixture does not crumble or crumble during operation, allowing you to lay the building material neatly and easily. The use of special plasticizing components in the cement mixture for aerated concrete allows for high-quality installation of facade walls. This mixture is very economical, provides good insulation properties, and is easy to use and lay. Thanks to its advantages, many workers still often work with this mixture rather than glue.
What to choose?
The use of glue is a rational, profitable and correct solution. When performing construction work, specialists are interested not only in how to lay aerated concrete, but also in what mixture to choose. After all, both the first and second options have a lot of advantages. It is necessary to take into account that the thermal conductivity of both mixtures is much higher than that of the blocks. From this it is obvious that the thermal insulation of the entire building depends on the width of the seam. If you use a cement mixture, the joint width will be approximately 9 millimeters. In the case of glue, the width of the seams does not exceed 3 millimeters.
Considering that the price of glue is higher, it can initially be assumed that when using it, the cost of installation work will also increase significantly. But, taking into account its minimal consumption, in reality the costs increase quite a bit, and the building ends up much warmer. But if you use a cheaper cement mixture, it will become clear that much more of it is needed and the cost of installation will inevitably increase. From this comparison it becomes clear that the use of glue when laying on blocks is a more rational solution, profitable and correct.
Laying technology
Before you start installation work with your own hands, you need to unpack the blocks and place them next to the row laying. When performing construction work on installation, it is better to use a special adhesive mixture. In case of such a choice, you will be protected from the formation of cold spells in the masonry areas. It is not recommended to use cement mixture, because, despite its cheapness, the consumption is much higher, and the seams look sloppy and too wide. Also, such a choice worsens the thermal insulation of the future home.
Before you begin masonry installation of blocks, it is worth installing special beacons. They are installed in abutment areas along the entire perimeter of the facade. They are needed for leveling in order to secure with their help a special wire that controls the evenness of walls and partitions. Secure the wire with galvanized nails. Also, we must not forget that the masonry instructions are important element any construction operations.
Mixing the mixture
To prepare, you need to prepare a special container and an industrial mixer. To knead the mixture, use a special dry composition and warm water. Continue beating until the mixture becomes homogeneous in consistency. It needs to be worked out over 20 minutes, which is why small doses are mixed. As the glue is used, it must be constantly stirred so that it loses its homogeneity.
If construction takes place at low temperatures, then it is necessary to use a special type of masonry mixture. It contains special components that prevent freezing, which allows it to maintain its characteristics even at low temperatures.
Marking
Laying of walls is carried out only after complete marking of building products. Marking is carried out along the axes of all surfaces of the future facade. After this, the material is taken, delivered to the installation site and distributed along the selected axes. When performing the dressing procedure, incomplete material is used, which will be located at the corners.
It follows from this that you first need to cut the products. This is not difficult to do, because cutting is done with a saw or hacksaw. To ensure that all structures are trimmed evenly, it is worth using a special ruler when marking. It is also necessary to pre-prepare those materials that will later be reinforced.
First, those blocks that are necessary for laying the first row are prepared, then the grooves of the rods are made for reinforcement during the installation of the facade.
Laying and reinforcement
The process of installing walls and partitions of a future building is not complicated, but it is important to do everything correctly. Only then will the whole process go quickly and the structure will be of high quality. First, building material and a special mixture for work are prepared. To complete the first row, it is necessary to perform a reinforcement procedure. After this, glue is applied to the surface and distributed with a special comb. The thickness of the seam should not exceed 4 millimeters.
Installation of masonry should be done with bandaging; each product must be moved at a distance equal to half of one structure. If the dressing is not performed, this will negatively affect the properties of the walls. The protruding mixture from the thickness of the seams cannot be rubbed down; it can only be carefully removed using a trowel. To ensure evenness of the masonry, a special cord is used. The evenness of the work done is determined using a building level and a special ruler.
At correct installation DIY walls cannot be ignored and the issue of waterproofing cannot be ignored. To perform this, a special mesh is used. The waterproofing mesh must be fixed to the walls in the area of contact with the foundation. Once the partitions are erected, they cannot be left defenseless. It is worth immediately performing façade and insulation operations. If it is not possible to do this right away, they try to cover the row with a special polyethylene mesh until it becomes possible to finish everything. Reinforcement is planned during preparation for construction. This is a mandatory operation if the wall is too long or if there is increased pressure on the box.
All jumpers whose length is more than 90 centimeters are subject to this procedure. And also all the bottom seams of the openings. This operation can be used using two technologies - using metal rods or using a special mesh. During installation, special grooves are cut into the blocks, where the rods are laid and glue is poured. This is followed by laying the next row.
During the construction of a building, a mesh is required to increase the strength of the facade and prevent the occurrence of cracks in the walls. The metal mesh is placed at intervals of 3 rows of aerated concrete blocks. The following materials are most often used to perform reinforcement:
- galvanized mesh;
- mesh made of basalt;
- mesh made of fiberglass.
Correct laying of blocks: how to lay blocks yourself
Building blocks - this material burst onto the domestic market relatively recently - in the second half of the last century. However, despite their relatively “young” age, building blocks have already managed to displace both the usual brick and time-tested wood from the building materials market.
After all, this material is characterized by a rather rare combination of qualities, which include sufficient strength, high heat resistance, enviable cost-effectiveness and the amazing simplicity that distinguishes the laying of blocks.
The laying process itself can be accompanied by only two relatively difficult moments - laying the first row of blocks and arranging the floors. In addition, in some cases it may be necessary to install a reinforcing frame. Let's look at these points in more detail.
So, before laying blocks on the foundation, that is, forming the “first row,” a novice mason needs to perform the following set of actions:
1. Using a cord and a plumb line, it is necessary to determine the location of the corners of the house and outline the boundaries of the walls of the building. After which, using a horizontal level, the highest point of the foundation is calculated - laying the blocks will begin from the corner located at the minimum distance from this point.
2. Next, along the outlined contour (the edges of which can be marked with special cords), a layer of moisture-resistant, cement-sand mortar is applied. This layer is necessary to level the surface of the foundation. It is best to buy the dry mixture for such a solution ready-made. After distributing the moisture-resistant solution over the surface of the foundation, a layer of insulator is laid on it, protecting the first rows of blocks from dampness. Roofing felt, roofing felt and other similar materials can be used as an insulator.
3. Next, at the location chosen for laying the first block, a relatively thin layer of mortar is applied directly to the insulator layer - after all, for the first block it was necessary to choose the highest point of the foundation - and the first block is “laid” on this mortar. After laying the first wall element, it is necessary to check the position of the block vertically and horizontally. The position of the block is adjusted using a wooden or rubber mallet.
4. After installing the first block, you can begin building the first row of the wall. Moreover, the masonry itself can be continued from the first block, however, it is best to immediately install blocks in each corner of the building. And only after that fill the space between the corner elements of the masonry. In this case, horizontal control must be done using a hydraulic level, and the outer boundaries of the blocks will be determined by the intersection of the marking cords.
After completing the first layer, laying the blocks will proceed with less difficulty. However, before starting the second layer of blocks, you should remember that the vertical seams of the bottom row must be bandaged with a whole block from the top layer.
However, most novice builders may have difficulty laying the second row. Therefore, before laying the blocks of the top row, novice masons need to remember the sequence of laying the first row and repeat all these steps, starting with the first corner element. Moreover, in the process of subsequent installation it is necessary to try to minimize the thickness of the fastening seams, because the heat resistance of the structure will depend on their size.
But before laying the fourth row of blocks, you need to take a short pause. The fact is that it is between the third and fourth rows, in some cases, that it is necessary to arrange a horizontal, reinforcing frame. To do this, one or two grooves are cut in the upper part of the third row blocks, into which metal rods with a cross-section of 6-8 millimeters are laid.
And in the future, this operation is repeated with similar frequency - the reinforcing frame will be installed between the seventh and eighth rows, the eleventh and twelfth rows, and so on. However, such a frame is only necessary for relatively fragile blocks made from certain types of foam concrete.
The next challenge for a new mason trying to figure out how to lay blocks on his own can be openings and slabs. Moreover, the entire complexity of arranging these elements will lie in the need to construct an additional reinforcing frame at the installation site of doors and windows. After all, a relatively fragile block may simply not withstand the weight of a reinforced concrete floor over a window or doorway.
However, there is simply no particular difficulty in the technology of arranging such a frame. Its elements can be laid out from ordinary bricks. And the only difficulty awaits the performer when leveling the horizontal of the upper edges of the reinforced concrete floor and the last row of blocks.
In a similar way, the problem of arranging interfloor covering. On the upper plane of the outermost row of blocks, a layer of denser material is mounted - the same brick on which reinforced concrete floor slabs are laid.
How to properly place blocks on the foundation surface? In this case, it is necessary to adhere to generally accepted work technology and not neglect the advice experienced craftsmen. Then it will be possible as soon as possible produce, preventing any defects at the initial stage of work.
Required materials and tools
To construct a structure made of aerated concrete, it is necessary to prepare a number of tools and additional materials:
- adhesive solution;
- sand with cement;
- construction drill, equipped with a mixer attachment;
- grater;
- rubber mallet;
- building level;
- cord or fishing line;
- scraps of reinforcement;
- spatula.
Technology of work execution
How to build a wall from blocks if the foundation is already ready? To install enclosing structures, it is recommended to follow the instructions provided:
- Drawing right angles. Work begins with drawing right angles on the foundation, for which a building level is used. They also check the diagonals of the building, which must be level. If any defects in the base are identified, they are leveled using gas blocks. Otherwise, after several rows of masonry, all non-joints will be visible to the naked eye.
- Reinforcing rods are installed along the edge of the structure. They are designed to stretch the fishing line, which indicates the direction of the masonry.
- Installation of building envelope elements on the mortar. How to lay the first row of gas blocks? In this case, it is usually recommended to use a cement-sand mixture (proportion 1:4). First, lay the corners, carefully checking them with a building level in all directions. This process should be approached responsibly, excluding even the slightest deviations. To move the gas block in the desired direction, use a rubber mallet.
- The first row of blocks is mounted on a solution that will provide reliable connection with the underlying structures. The end sides of the material are connected to each other with special glue. It is also used for the installation of all subsequent rows.
- During the installation process, it is recommended to constantly remove any mortar that protrudes outward. To do this, use a spatula and a grater.
How to lay the first row of blocks on the foundation
Types of adhesive mixtures
If foam concrete blocks are used in construction, special adhesives should be used for their installation.
The most commonly used types are:
- standard adhesive composition. Designed for installation of most materials used in private construction;
- frost-resistant compounds. Able to withstand low temperatures without losing their properties;
- heat-saving compounds. When creating seams, the area of freezing is limited.
The price of adhesive solutions depends on their brand and manufacturer. Domestic options are cheaper than imported analogues. To prepare the glue, just follow the instructions on the package. The dry powder is mixed with water, and a construction mixer is used to combine the ingredients.
How to lay blocks on a foundation to achieve better quality? To facilitate this process, you should follow the advice of experienced specialists:
- waterproofing is laid on the finished foundation, which will prevent the spread of moisture from the soil to the walls;
- for more reliable fixation, it is recommended to buy materials with special grooves;
- It is best to install the guide cord along the outer edge of the gas block, which will facilitate its installation;
- Before installing aerated concrete, it is recommended to go over its surface with a grater to remove small irregularities;
- if during the installation process there remains a gap of 10 cm, it is recommended to reduce the size of several blocks rather than install a small piece;
- It is advisable to lay the reduced pieces on different sides, and not in a row;
- foundation unevenness can be easily leveled out with the thickness of cement-sand mortar;
- to increase the strength of the enclosing structures, it is recommended to lay reinforcement with a diameter of 6-8 mm between the third and fourth rows;
- additional reinforcement of the walls should be done every 3-4 rows along their entire height;
- When installing each row, you should not forget about bandaging, which significantly increases the durability of the enclosing structure.
If you adhere to this technology, there will be no question of how to lay the blocks to form reliable and durable enclosing structures.
Moreover, all of the above operations can be performed even by a novice builder.
How to lay blocks with your own hands + step-by-step instructions
So, after the foundation has been poured, a rather important stage begins, namely the laying of blocks, which is not as difficult to do with your own hands as it might seem. Today we propose to consider this very topic, and we will talk about low-cement blocks.
Before you start, it's worth preparing everything necessary tools. First of all, you may need tools such as buckets, shovels and a hammer. Next, arm yourself with special devices, namely a mason’s pick, a trowel or trowel, a plumb line and a building level. To break the walls, you may need a strong thread called a “chalka”, as well as a tape measure.
It is best to buy thread on a handle, from the company Stauer, because it fits perfectly in the hand and is bright yellow, which is clearly visible even at dusk.
Tools
As for electrical tools, you may need a hammer drill, a grinder (to cut off reinforcement or corners to create jumpers). To mix the solution, it would be nice to have a concrete mixer on hand, as well as a barrel of water (can be made of metal or plastic). To create jumpers from corners you will need a welding machine. If you plan to lay two or more floors, then it is better to carry pallets with blocks along the floor not by hand, but to use a cargo trolley, which you don’t have to buy, but rent at a tool rental point.
Materials
Directly for installation you will need low-cement blocks, cement mortar, water and sand. The lintels that will be located above the door and windows require metal - reinforcement, angle or channel. As a rule, a lintel made of reinforcement is used over the doors, the diameter of which is from 1 to 1.4 cm in several rods, and for windows it is better to use corners. For garage doors, the best option would be to make a lintel from channels - much will depend on the weight of the door and the width of the opening. For beacons it may be necessary wood slats, as well as dowels; For scaffolding, use boards and pallets, and you can fasten it all with nails. If you have a construction goat, then that's even better. If you live in seismic regions, then you will need a masonry mesh, or A240 0.6 cm reinforcement. But it will be much easier to find the mesh and use it, and it is better not to use fiberglass reinforcement as wall reinforcement. if you plan to cover the entire house with facing bricks, then you will need a notch for the outlets, which will be embedded in the seam. This is where you can use fiberglass reinforcement.
Work process
Wall markings
Any work begins with the need to clean the base from debris and dust. If we are talking about the first floor, then you should remove it on the foundation, and if you are laying the second and higher floors, then we will start with the ceiling. All you need to do is sweep the walls with a broom. As was previously done when laying out the foundation, now it is necessary to correctly break the corners of the building so that they turn out straight everywhere, because this will be the last moment when it will be possible to correct everything, since otherwise errors in geometry will crawl out onto the ceiling and roof. The best option To solve the problem, a surveyor will be called in, who will cut right angles with an accuracy of 0.3 cm, but this will cost several thousand rubles, and usually such a master is called only to break down a building or to build houses that are too long.
Small houses can be demolished without outside help. To do this, you will need a roll of rope and a construction tape, preferably made of metal. The technology is quite simple - place the blocks dry and take measurements of the diagonals of the resulting rectangle. The accuracy will be within 0.3-0.5 cm. You should take into account the fact that a metal tape measure does not stretch, but a thread or fabric tape will stretch, and quite a lot. If you do not plan to do cladding, then you can extend the block or brick beyond the vertical border of the plinth to approximately 1/3 of the brick/block. BUT try not to abuse this, especially if the buildings are higher than 1 floor. When the main corners of the building are exposed, it will be possible to simultaneously expose additional ones, if any. At the same time, it will be possible to put up partitions, especially if there are no columns, so that they can be laid at the same time as the outer walls.
Laying blocks with your own hands in the first row
Before starting the laying of the first row, it is necessary to check all the vertical type marks on the foundation, because the first row is the most important stage. If you do not level the base with mortar or there are large differences, then there is a high probability that the walls will crack. The check is carried out with a regular spirit level or a laser level, which was set during marking. If deviations from the horizontal are up to a maximum of 2 cm, then you can level out the unevenness with a solution. If it is more, then it is better to fill the belt with reinforcement and make sure that the horizontal level of the concrete is normal. The first row should be laid on roofing felt, cut the roll in half and laid directly on the foundation. This is done in order to cut off capillary moisture from the blind area and the ground.
In seismic areas where the standard value is higher than 6, such waterproofing is prohibited! During a seismic wave of a lateral type, a building can be moved from its foundation and completely collapse. For this reason, waterproofing is made from mortar if roofing felt cannot be installed. So, before starting masonry, check the base again for debris and wet the base. The mortar is placed on the first corner stone and the second on the opposite corner with the holes downwards, and you also need to carefully monitor the height of the masonry. Be sure to check the side edges and ends of the blocks by level so that everything is only vertical.
When all the blocks stand exactly horizontally and vertically, you should stretch a cord between them and align them along it. Now, in the same way, make a perpendicular wall - this technology is called “bringing corners.” While you are making the second and third corners, on the first floor the solution will have time to lose its mobility, and the block will lie tightly. Once this has happened, you can begin laying the first row further. If we are talking about a seismic region, laying in a wasteland is prohibited. We are talking about work when only horizontal rows are placed on the mortar, and the vertical rows are not filled with mortar. Thus, masons often try to save time, and then plasterers will have to tinker a lot and seal the cracks.
For this reason, apply two portions of mortar on the end side of the next block where the block on the foundation/slab will be laid out and carefully place the block, almost touching the thread. With a light tap of a pick or trowel, the block should be tapped to the first block and then aligned with the thread so that the block touches it slightly. When everything is finished, check the side edge for verticality. We do the same for the rest of the wall.
Wall laying and mesh reinforcement
The second and all other rows will hardly differ from the masonry of the first row, but the main difference will be that the corners, in addition to the level, will need to be checked with a plumb line. The more rows, the greater the accuracy of the plumb lines, because the level has quite large errors. Typically, plumb lines are bought in stores in the form of metal weights, to which you must attach a rope yourself.
To mark the load, you should make a conical hat in order to know exactly the point where it will look. For masonry and plastering, it is best to use Armenian plumb lines rather than store-bought ones. It was invented by builders to do work accurately and quickly, and not be distracted by anyone.
Yes, to lay aerated concrete and other blocks with your own hands, you will need an Armenian plumb line, which is shaped like a spinning top, and not a thin nylon thread is inserted into it, but a thick rope. At the second end of the rope there should be a pipe where the rope is threaded in the middle. Inside the hole, the rope will pass with force, and behind the pipe it will be tied with a knot. It will be the same size as the plumb line.
To measure, you can easily measure the required length of rope, and attach the end of the tube to the block, and release the plumb line down. A light touch will indicate verticality, and other deviations can be easily noticed and corrected in time. It is unlikely that you will be able to buy such a plumb line, but you can make it yourself. In addition, it would not be superfluous to lay a mesh for “resistance from vandals,” because in most crime reports you can often see cases of theft from stores in a tree without signals, where the store was broken into by breaking the wall.
Bonding masonry in a block wall
As a rule, external walls are placed in a block, and internal ones in half. Bandaging of the partitions should be at least 30% of the block in the run. It is unlikely that we will be able to come up with something new here. External walls can be bandaged in different ways.
Lintels in a block wall
In a block wall above the opening of windows and doors, it is necessary to install lintels, and in load-bearing external walls, a depth of embedding into the wall of 0.2 meters is allowed, and with an opening width of more than 1.5 meters, at least 0.25 meters is allowed; for other cases, the optimal figure is 0.35 meters. You can pour all the concrete, but it is inconvenient and time consuming. To implement it, you will need to install formwork, reinforce it with a spatial frame and fill it. In this case, the laying will be suspended. If you do everything yourself, then you can use this method - although it is the most labor-intensive, it is also the cheapest, and nothing will stick out from the wall.
Ready-made lintels are heavy and are placed in several pieces per row to match the thickness of the wall. This method is much faster, but it will be difficult for 1-2 people to do it while standing on scaffolding. During private construction, reinforcement and a corner are most often used as a lintel. In partitions, you can use 1-1.2 cm reinforcement, 4 pieces each, which will be embedded in the masonry, and pull up the board from below, and then spread it with a stand, and apply mortar through the rods. When the cement becomes less mobile, the blocks can be laid. But for external walls, which are much thicker than partitions, corners are used. To do this, cut it to size and weld the reinforcement together through the strip in several places. Next, prime the metal to prevent rust and install it on the block. Apply the solution to the shelves and install the blocks with the holes facing up. This will be the most expensive method, but very reliable and fast.
Masonry mortar
A typical concrete mixer, which is capable of producing in a home/factory environment, contains about 10 buckets of materials. One mixer will require half a bag of M500 cement, 8 buckets of sand and approximately 1.5-2 buckets of mortar. As a result, we get an excellent 1 to 5 solution with excellent strength. You can use any sand, but it’s better to wash it, because it has practically no shrinkage. To prevent the solution from settling, you need to add liquid soap to it. If it is good, then 0.8 liters will be enough for all the given proportions, but there are soaps of such quality that you have to pour up to 2.5 liters - it is better not to use it.
The mixing technology is as follows:
- Lay 2 bricks and place reinforcement between them. A bag of cement should be placed on top of it in front and leveled in the middle. Using a trowel, cut the bag on one side, and then lift the bag using the reinforcement. The cement should be carefully divided in half, cut and use one half.
- Pour 1.5 buckets of water into the mixer.
- Then carefully pour in the cement and start the device.
- After 1 minute of work, sand begins to be poured in little by little.
- When everything is finished, add water or sand to adjust the fluidity of the solution.
Please note that it should not be liquid and not dry - not roll off on the trowel, but not clump.
Laying the first row of aerated concrete blocks is a very important stage of construction, since the next rows and the evenness of the walls as a whole depend on it. In order not to complicate the laying, the first row should be laid as evenly as possible.
So, to begin with, we will briefly describe the masonry algorithm, and for more details about each stage, see the text below. Tools, waterproofing, preparing mortar, leveling blocks, reinforcement, we will talk about all this in this article.
Brief technology for laying the first aerated concrete row:
- Level the surface of the foundation with mortar;
- If it is already very smooth, then remove dust from the tape;
- Spread bitumen mastic on the tape;
- We lay waterproofing, for example, roofing felt;
- We determine the highest angle with a hydraulic level;
- We lay gas blocks in the corners on the solution;
- We align the blocks horizontally and vertically;
- We stretch the thread between the blocks;
- We lay the remaining blocks on the solution along the thread;
- We reinforce the first row of blocks with reinforcement.
Marking and preparatory work for masonry
Before starting construction work, you should prepare the necessary tools:
- Construction level or laser level;
- Hydraulic level;
- Roulette;
- Cord plumb line;
- Special saw and trowel for aerated concrete;
- Square;
- Trowel;
- Rubber mallet;
- Wall chaser.
Horizontal waterproofing under masonry
Laying the walls must be preceded by waterproofing the foundation, so that in the future the moisture of the foundation cannot be transferred to the aerated concrete. For this procedure, modern bitumen materials are best suited, which are sold in rolls, are easily cut into pieces with a construction knife and fit well.
Brief instructions for horizontal waterproofing
- Dust the surface of the tape;
- Apply bitumen mastic to the tape;
- Cut the waterproofing rolls into strips of the required width;
- Lay on the tape with an overlap of at least 150 mm;
- You press.
First, it is necessary to determine the highest corner of the foundation, where the first aerated concrete block will later be laid. It is determined using a laser level or hydraulic level.
Proper marking is the most important factor influencing the correctness of the masonry and the speed of work itself. Using a laser level will help you avoid mistakes, but if you don’t have one at your disposal, a level, tape measure and proper professionalism will be enough.
The construction of an aerated concrete foundation requires great care and attention in terms of the horizontal plane, because the future stability and reliability of the structure depends on this.
The first row is laid only when the difference between the highest and lowest angle of the foundation does not exceed 3 cm.
For laying the initial row of aerated concrete blocks, as a rule, an ordinary cement-sand mortar is used, which is prepared using standard technology with a substance ratio of 3:1. In this case, thick seams will be more of an advantage, because they will allow you to make adjustments and achieve the ideal horizontal position of aerated concrete.
Technology of laying gas blocks
Laying the first row
The first block is laid in the previously determined highest corner, after which its correct position should be checked on all sides. Next, three more blocks are laid in other corners. To adjust the height on the solution, a rubber mallet is used. The use of metal tools is excluded, as they can easily damage porous aerated concrete.
When the corner walls are laid, a cord is pulled between them. The cord will help control the correctness of the masonry.
If the length exceeds 10 m, it is necessary to secure another block in the middle of the span.
Also, in order to control the quality of masonry, a comparison of diagonals is performed. Equipped with a tape measure, you need to measure the distance between diagonally opposite corners. The resulting values must be identical.
Each block of the first row is aligned plane, vertically and horizontally. For leveling, use a rubber mallet.
Most often, at the end of laying a row, an additional element is required, which is prepared from a whole aerated concrete block. An even mark is carefully applied to the surface of the latter, along which the excess is then cut off, or a special triangle is used.
Aerated concrete can be sawed very easily using a hand saw with large teeth.
Adjacent blocks must have the same height, so to maintain it you will need a level and a special grinding float. All dust and small particles must be removed immediately using a soft brush.
It takes approximately 2-4 hours after laying the blocks (depending on temperature) for the solution to harden well. After this, you can begin further construction.
Aerated concrete blocks, due to their cellular structure, are easily susceptible to physical impact, so in the future, due to changes in humidity and movement of the foundation, cracks may form. To avoid such troubles, reinforcement is used - strengthening the masonry with metal reinforcement. The profile of the latter should be corrugated, the cross-section of the rods should be about 8-10 mm.
It is optimal to use rods A-III for reinforcement. For aerated concrete blocks with a width of over 250 mm, a pair of rods is required, while for partition walls with a similar indicator of 150-200 mm, one metal rod is sufficient.
The reinforcement is placed in recesses made in advance with a wall chaser, and all dust and sand particles must be removed with a brush. The size of the grooves must be larger than the diameter of the cross-sectional rods so that they fit inside without resistance.
The grooves are made at a distance of 60 mm from the edges of the block, and a special aerated concrete adhesive is poured inside, which will secure the metal rods and protect them from corrosion.
Due to the fact that it is extremely difficult to make an even strip of grooves along the entire length of the first row of blocks, a template is used, which can serve as a fixed board of the required width.
It is necessary to make grooves with rounding at the corners; a similar bend is first given to metal rods. The reinforcement is connected by an overlap with a length of about 30 cm.
The grooves with the laid reinforcement are once again filled with glue and leveled with a spatula flush with the plane of the gas block. The laying procedure of the first row is completed.
Many self-builders want to save on everything, including reinforcement, but such savings can lead to even greater costs in the future.
Subsequently, ignoring this process can come out sideways in the form of cracks on the walls and violation of the integrity of the structure, so we advise you to resort to reinforcement without fail, and in general, to do all the stages according to the technology. Then your aerated concrete house will last a hundred years.
On the use of fiberglass (composite) reinforcement
Let’s also say a little about fiberglass reinforcement, the use of which rather dubious not always justified in our opinion.
Reinforcement is used to give structures greater rigidity. This rigidity is ensured due to the fact that the reinforcement works in tension, and a parameter such as the elastic modulus is responsible for this.
In other words, if you start stretching the reinforcement, it will begin to lengthen; this is essentially the modulus of elasticity (MU). And the lower the stretch percentage, the better.
For example, for fiberglass reinforcement, MU is equal to 45,000 MPa, for metal reinforcement of the same section - 200,000 MPa.
This means that fiberglass reinforcement stretches 4 times more. What conclusions can be drawn from this? Steel reinforcement makes the structure several times stiffer and stronger.
