Foam block is one of the most versatile building materials. But at the same time, you need to know how to lay foam blocks correctly. During its production, a foaming agent is added to the mixture of sand, cement and water.
It forms empty cells inside the block. Its properties are very unique: lightweight, environmentally friendly, long service life, able to withstand about 5–7 hours at high temperatures of an open flame. It is easy and convenient to work with, it has good thermal insulation properties, and its low cost will be affordable for anyone who wants to build a house with their own hands. Its “relative” in terms of internal composition is often used - aerated concrete. These two building materials are often confused with each other. Aerated concrete differs in that it is made exclusively using an autoclave, where hydrogen bubbles are released at high temperature and pressure.
Features of laying foam blocks
Before laying out the first row, you need to know several important aspects:
- You can press the blocks together using glue and cement mortar;
- The seams between the foam blocks should not have voids;
- Reinforcement of masonry is a prerequisite;
Still, laying the foam block on glue will save both time and material. When laying blocks on a mixture of cement and sand, it is necessary to initially wet them so that the solution dries evenly. Then the masonry will be strong, compared to laying with glue. You can use either imported or domestic glue.
How to lay foam blocks
In the first row of laying foam blocks, it is imperative to use a cement mixture. The foundation is ready, which means you can lay an even layer of cement-sand mortar (about 2 cm) on it, then lay down a layer of waterproofing. This can be hydroisol, rubemast, bikrost. The second layer of cement mixture is applied over the waterproofing and the first row of foam blocks is laid. Aerated concrete is also laid according to these rules. A strong foundation directly affects the smooth geometry of the walls. If you are building a house with your own hands, you should know that the laying must begin from the corner of the future house. To avoid voids, it is necessary that the glue or cement mixture evenly covers the surface.
Reinforcement
To increase the strength and reliability of the structure, reinforcement should be used. To prevent the weight on the wall from creating cracks at the seams, reinforcement or wire mesh (4-5 mm) should be used every 4 rows. For it, potholes are specially cut out with a grinder or wall chaser. This is easy to do, just like aerated concrete, foam block is easy to process. It is important to know that if the distance from corner to corner of a blank wall is 3 m, additional reinforcement is performed.
Last stage
You can check the wall for unevenness using a level or a stretched cord and a plumb line. You can use a laser level or level. The masonry is completed with special monolithic U-blocks with reinforced metal fittings. The thickness of the belt should be at least 10-15 cm. Construction with your own hands can be continued after 25-30 days, after the concrete has completely hardened.
Subtleties when laying foam blocks:
- The first thing you need to pay attention to is the foundation. If it is mounted from concrete blocks, then a reinforced concrete belt must be attached to all this, or the foundation must be poured with a solid monolith;
- For laying on glue and cement mixture, pay attention to the geometry of the blocks, they must be even and the same size;
- The glue does not carry any special warnings, the main thing is that it has good adhesive properties;
To avoid heat loss, when using a cement mixture, foam blocks should be laid in two rows, thereby closing the vertical seam. If you are using glue then this is optional.
It’s easy to figure out how to lay foam blocks or aerated concrete. By following all the above tips, you can easily build a house with your own hands, and experienced builders will tell you that laying a house out of foam blocks is not only profitable, but also much easier than, for example, building a house out of brick. Aerated concrete is also laid according to the same principles. The main advantage that attracts many people to build from foam blocks is the ease of construction with their own hands. It is enough to erect load-bearing walls and one supporting partition, and you can design the space as you like, provided that the foundation is reliable. Now everyone knows how to lay foam blocks correctly, now all that’s left is a little work to do.
Foam block is a relatively new building material, and if bricklaying technology has developed and improved over thousands of years, the search for the optimal way to lay foam blocks continues. This is due, first of all, to the low specific gravity of foam blocks, high porosity and low strength. At the same time, the attractive aspects of the foam block, its high heat-insulating and “breathing” properties, the possibility of quickly erecting a building from the foam block at a fairly low cost, make it in demand in private construction. But the question arises: how to lay foam blocks correctly?
Main distinctive points:
- In addition to cement mortar, adhesive mortar can be used to bind blocks together;
- completely filled seams, there should be no voids;
- the masonry must be reinforced;
- A reinforced concrete belt is laid on top of the masonry before installing the concrete floor.
What to choose - cement mortar or adhesive knowledge can help foam block manufacturing technologies, of which there are only two: either the foam concrete mixture is poured into molds for hardening, or blocks of the required size are cut from the foam concrete monolith. The second method involves fewer deviations from the specified parameters, i.e. the blocks are all identical. In this case, it is faster and more convenient to glue them together using a special tool designed for this purpose. adhesive solution. A building erected using this technology has good geometry and smooth walls, which allows significant savings on finishing, both time and materials.
When laying molded blocks, cement-sand is used solution of classic proportion 1:4. The solution helps smooth out the unevenness of the blocks and deviations in their dimensional parameters. Before laying the blocks on the cement mortar, they must be moistened, otherwise it will be impossible to ensure uniform drying of the mortar, which will affect the strength of the masonry.
The order of laying walls
First row of masonry in any case, it is performed on cement mortar. A layer of sand-cement mortar, about two centimeters thick, is applied to the foundation and covered with a layer of waterproofing. As a waterproofing material You can use modern roll materials, their choice is quite large: rubemast, hydroisol, bikrost, but it is better to refuse traditional roofing material. A layer of cement mortar is applied again on top of the waterproofing layer and the first row of foam blocks is laid on it.
The corner block is placed first, i.e. cornerstone. The laying is carried out in two rows, and it is necessary to carefully monitor the uniform distribution of glue or mortar over the surface of the block, horizontal and vertical, in order to avoid the formation of voids in the seams. A special notched trowel is used to distribute the solution.
To increase the stability of the masonry and protect against cracks, reinforcement is laid every 3-4 rows of blocks. This can be done in two ways:
- When laying on cement-sand mortar masonry welded mesh is laid in the interblock seams. You can take a ready-made mesh made of wire 4-5 mm thick.
- When laying on glue, the reinforcement is placed in grooves specially cut for this purpose - grooves. This is easy to do using a wall chaser or saw, since the foam block material is easy to process. A grinder or circular saw will also be required for possible cutting of blocks.
Crowns the masonry of foam blocks special monolithic concrete-reinforced belt 10-20 cm high, which will take the load from the floor slab and ensure its uniform distribution. Its width is slightly smaller than block masonry, since the cold concrete belt requires additional insulation. To install the ceilings of door and window openings, prepare blocks with a U-shaped cutout, the width of which corresponds to the ceiling along with insulation.
As you can see, building a house from foam blocks is not that difficult, and experienced masons are confident that laying foam blocks is much easier than laying bricks.
Blocks made of cellular concrete make it possible to connect or glue them traditionally. Making decisions related to the choice of masonry technique can have an impact on further heat loss in the house. With the development of building materials, doubts arise about the use of methods for connecting brickwork elements. Adhesive for foam blocks makes it possible to create a thin-layer seam with a thickness of 1 to 3 mm. Compared to traditional 15 mm seams, this solution provides many significant advantages in laying foam blocks.
Advantages of a thin seam when laying foam blocks
Minimal seams between blocks eliminate cold bridges - due to the thickness of the seam, there is a significant impact on reducing heat loss. It should also be kept in mind that any mixture that does not combine elements of cellular concrete is a material that conducts heat 4 times more easily, so the less it is, the better the wall will be insulated. Heat loss from 1 mm joint thickness in a single-layer wall made of foam blocks is only approx. 4%. A wall built from the same blocks, on mortar with a traditional joint thickness of 12 mm, generates heat losses that exceed 25%.
A thin seam gives greater load-bearing capacity of the wall
One may come across a misconception, especially among “experts,” that the thicker the seam layer, the more the wall can withstand greater loads. The situation is completely opposite - the seam is the weakest element of the wall. The thinner its layer, the stronger the wall and can withstand more loads. Here we can use an analogy for superglues, which glue two surfaces together within a few seconds, forming a strong connection only if a very thin layer is used.
The use of a thin seam provides economic advantages
It is worth noting that the cost of making 1 m2 of wall also depends on the quantity and price of the mixture that we must use to connect the brickwork elements. Walls made of 20 cm thick blocks have an adhesive consumption of approx. 2.4 kg and approx. 0.6 liters of water for every m2 of wall. Using cement mortar with the same wall thickness, 24 dm3 of mortar is consumed - 7.5 liters of water and 42 kg of dry mixture.
Step-by-step instructions - how to lay foam blocks on glue
Foam concrete blocks are placed on an adhesive solution. They require a very smooth and clean surface, so the surface of the blocks must be sanded and dust removed before applying the solution. To ensure that the seam has the appropriate thickness, the solution is applied with special trowels:
- The surface of the first layer of brickwork elements must be leveled with a special trowel and leveling solution, and then thoroughly cleaned with a brush from small particles and residues after grinding. With the same grater, we can remove uneven surfaces from vertical surfaces.
- It is necessary to lay waterproofing on the foundation. The first layer of blocks should be laid on a base of ordinary cement-lime mortar. Place the first element directly on the prepared mixture. You need to remember to maintain the ideal level of the first elements and their alignment.
- The contents of the bag of glue must be poured into a container with a measured amount of water recommended by the manufacturer, then mixed using a mechanical stirrer until a homogeneous mass is obtained so that there are no lumps in it.
- A layer of adhesive solution 1-3 mm thick is applied to the cleaned surface. The solution should be applied using a regular spatula that matches the width of the walls. When laying on thin-layer mortar, the blocks are not sprayed with water. Control of the correct location of masonry elements in the corners of the building, as well as along the walls, should be checked using a level and a cord. Unevenness of individual brickwork elements is corrected using a rubber hammer.
- In the same way we lay each subsequent layer of foam concrete.
- Before plastering the surface with mortar, fill in the potholes and damage that may occur during masonry. Thanks to the use of adhesive solutions, as well as special tools designed for applying glue, it is possible to significantly reduce time and optimize glue consumption.
Considering that the blocks are produced with high precision, this allows for a number of advantages arising from the possibility of using glue for foam blocks. The choice of this technique for connecting brickwork elements is the optimal and safe option, regardless of historical habits and solutions that do not withstand the pressure of current technical requirements.
Foam blocks as a building material appeared relatively recently. Unlike brickwork, the technology of which has developed over many centuries, the methods are still being improved. This building material has low specific gravity and high porosity along with excellent heat-shielding properties. And the speed of construction of houses from foam blocks and the relatively low cost of this material make it very popular. Therefore, instructions on how to lay foam blocks will be very helpful.
Like aerated concrete, foam concrete can be laid on a cement-sand mortar or on a special glue. The choice of solution depends on the manufacturing technology of foam blocks. Foam block masonry needs to be reinforced. Before installing the ceiling, a reinforced concrete belt is placed on top of the masonry.
Tools for laying foam blocks:
- drill with a mixer attachment for mixing the solution;
- drill attachment for making holes for electrical points;
- trowel;
- rubber hammer for leveling blocks;
- building level;
- hacksaw and angle for cutting foam blocks;
- a grater and a plane for leveling the surface of the masonry before the next row and leveling the surface of the walls before applying plaster or putty;
- wall chaser;
- electric router (for making grooves in masonry for laying reinforcement);
- carriages for uniform application of the adhesive solution;
- wide brush for removing debris and dust from walls.
The production of foam blocks can be done in two ways: injection molding and cutting.
The injection molding method differs in that the foam mixture is poured into molds and hardens in the form of durable blocks. Such blocks are placed only on cement-sand mortar in a ratio of 1:4. Before you begin laying foam concrete, it must be moistened with water to ensure uniform drying of the solution.
The production of foam blocks from a large block, dried in an oven and cut into elements of the required sizes, is a cut manufacturing method. To lay such blocks, you can use special glue. This manufacturing method differs from injection molding in its high dimensional accuracy, the error of which is no more than 1 mm.
Cast foam blocks may have unclear lines, so they need preparation before work:
- cleaning sharp corners and large burrs;
- cutting of significant irregularities;
- removing chips.
How to lay foam blocks? Cast ones are placed on a cement-sand mortar. It should be applied with a notched trowel or trowel. The thickness of horizontal seams should be 10-15 mm, and vertical seams - 8-15 mm.
Cut foam blocks are placed on a special glue.
The surface of the wall is smooth, which greatly simplifies its further finishing. The thickness of the joints when laying such blocks does not exceed 2 mm. There are no “cold bridges” in such walls, which improves its thermal insulation characteristics.
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Foundation arrangement
The reliability and durability of masonry made from foam concrete blocks primarily depend on the quality of the foundation. It can be made monolithic, or it can be assembled from concrete blocks with a reinforced concrete belt.
Foam blocks have fairly low hygroscopicity, but they still react negatively to the appearance of moisture, absorbing it. Therefore, it is necessary to protect the walls from possible water penetration. When laying the foundation, horizontal and vertical external waterproofing must be done. The level of the base should be raised above the blind area by at least 50 cm.
The technology for foundation waterproofing has the following order:
- a layer of cement-sand mortar 1-2 cm thick is distributed over the foundation;
- waterproofing material is laid (for example, waterproofing);
- cement-sand mortar is applied.
Only after these works can it be erected.
Laying foam blocks is a very responsible task. Improperly laid material loses its quality over time and may crumble. In particular, in conditions of high humidity, the foam block loses its shape, so the walls must be properly waterproofed.
Such masonry does not tolerate any foundation deformations, so many experts recommend creating a base in the form of a monolithic slab, which can be either a solid reinforced concrete structure or made of concrete blocks. In this article we will look at how to correctly lay foam blocks and what is the best place to lay foam blocks on in order to avoid harmful deformations.
About foam concrete blocks
This material can be produced in two ways:
- Molding method. The foam mixture is poured into special molds, where it hardens to form a durable block. Laying of such material is carried out exclusively on cement-sand mortar.
- Cutting method. A large block is formed from the foam, which is dried in an oven and cut into products of the required sizes. In this case, specialized adhesive mixtures can be used for installation. This manufacturing method is characterized by high precision, and the error in the production of each block is no more than 1 mm, while material made by injection molding may have a slightly larger discrepancy.
Characteristics of foam concrete blocks
The building material has the following characteristics:
- Reliability and durability. A properly laid foam concrete block is a virtually ageless material.
- Heat. The high thermal resistance of such walls allows you to reduce heating costs by 30%.
- Excellent sound insulation.
- Easy to use. Any home craftsman who has worked with brick or cinder block can lay out masonry from foam blocks with his own hands. There are only a few nuances here, which will be discussed below.
Since even non-professional builders can lay cinder blocks or bricks correctly, you won’t have any special problems with this material. - Environmental friendliness. Over the entire period of operation, the material does not emit harmful substances into the air, second only to wood in terms of environmental friendliness.
- Foam blocks and gas blocks are made in various sizes and shapes.
- Relatively light weight allows you to significantly save building materials by laying the foundation at a shallower depth.
- Fire safety. According to test results, the material has the first degree of fire resistance.
- Wide range of applications.
Today there are the following types of foam blocks:
- Structural. Which are used to create loaded structures that carry additional load in addition to their weight.
- Thermal insulation, used for insulation purposes.
- Thermal insulation and structural, combining the properties of the two previous types.
Many home craftsmen are interested in the following question: “Is it possible to lay floor slabs on a foam block?” Of course, you should build load-bearing walls yourself using foam concrete blocks of grade 600 (and higher) only.
Foundation for masonry made of foam concrete blocks
As mentioned above, foam blocks require a reliable foundation that would minimize any deformation and pressure from the soil. And a monolithic base is an excellent choice.
However, it has several significant disadvantages:
- The price of such a foundation is quite high; moreover, its construction is unjustified due to the relatively low weight of the foam block structure.
- With such a foundation, you will not be able to equip a basement, which in some cases significantly expands the usable space of the house.
Considering these factors, many home craftsmen prefer columnar or strip bases, which, with the right approach, can also become a reliable basis for such a house.
When a builder wonders whether it is possible to lay floor slabs on foam blocks, this means constructing a two-story structure. And if a columnar foundation is aimed at lightweight buildings, then a strip foundation may be quite suitable for a two-story house, so we will consider the features of working with this material.
The instructions are:
- We mark the territory using pegs and a fishing line that is stretched between them.
Advice!
When marking, you should take into account the allowances for arranging the formwork, which amount to a total of 15 cm.
- We dig a trench according to the markings. Its depth should be about one and a half meters. If you are planning to arrange a basement, the depth should be increased to at least two meters.
- We make a base for the formwork, which is made from wooden beams. Boards are nailed to the inner sides of the beams, forming the formwork.
- Pour a layer of sand (about 15 cm) into the formwork, which must be watered and compacted tightly. Water generously and evenly.
Advice!
In order to check how well the sand layer is compacted, you just need to step on it. If no trace remains, then everything was done correctly.
- Using a construction stapler, we attach plastic film to the formwork.
Advice!
The film cannot be used in winter, as it will lose its elasticity, which will lead to poor quality of the foundation.
- Take steel rods and wire and tie the reinforced frame together. The design of such a frame is not of fundamental importance; the main criterion here is strength.
- Now you should start pouring concrete. For this, a mixer machine or a specialized pump is used.
- We distribute the concrete evenly over the formwork using a wooden lath. Make sure there are no empty spaces or protrusions on the surface.
- After a month, you can start laying walls.
Related articles:
How to lay foam blocks
It’s not for nothing that home craftsmen are interested in how to lay foam blocks correctly. Once you figure out how to lay a cinder block on a foundation, you can easily handle foam concrete blocks.
And in order to carry out the work correctly, you should consider several recommendations from professionals:
- You should start laying foam blocks with your own hands from the corner.
- Experts recommend laying the material in two rows of 20 cm each. If you take into account the facing layer of half a brick, the thickness of such walls will be 52 cm, and if you add mortar joints - 55 cm.
- In order to efficiently install foam concrete blocks, you should control the remaining voids at the seams. Vertical, horizontal and inter-row seams should be filled with glue or cement so that no cavities remain. Remaining composition should be removed as soon as possible.
- In order to achieve maximum strength, the masonry is reinforced with a thin metal mesh.
- To apply the composition evenly, use a notched trowel.
- Is it possible to lay foam blocks in winter? It is possible, but it is still better to carry out the work during the season (spring-autumn).
Carrying out work
Now let's figure out how to properly lay masonry from foam blocks.
Since laying a foam block on glue is as simple as laying it on concrete, we will consider both options in one instruction:
- First, the material must be cleaned of dust, dirt, snow, etc.
Advice!
If there are chips on the blocks, it is necessary to remove chamfers and sharp corners.
- We start laying from the corners. The first row should be laid on a waterproofing layer. Roofing felt laid in 1 or 2 layers can be used as a waterproofing material.
- The laying is carried out using sand-cement mortar in a component ratio of 1:3. The thickness of the seam does not exceed 30 mm. If the masonry is carried out in dry and hot weather, the material should be moistened before work.
- Having laid the first row, we check its horizontalness with a level. If minor irregularities are found, they can be removed using a grinding tool.
- Subsequent rows should be laid out on a light solution.
Stick to the following seam thickness:
- Vertical – 8-15 mm.
- Horizontal – 10-15 mm.
Advice!
When using an adhesive composition, the thickness of the seam is indicated on its packaging.
Usually it is 1-2 mm.
- The solution should be applied along the entire length of the block, and then leveled using the notched side of a spatula or trowel.
- The foam block should be lowered from above onto the solution, and it should not be moved more than 5 mm.
- You can place the blocks with light blows of a rubber hammer, while shaking them.
- Do not forget about the dressing - it must be correct. Vertical joints should be offset by no more than 0.4 block heights.
Conclusion
Foam concrete blocks are an excellent building material. And in order for the building built from it to serve you for many years, you need to adhere to all the rules described above in your work. In the video presented in this article you will find additional information on this topic.
