Novice builders often face the problem of correctly calculating the required amount of material. In order not to be mistaken with the numbers, it is necessary to take into account the dimensions of the material and the future structure, the necessary supply for cutting, debris and other features. Our article is devoted to the intricacies of calculating such a building material as cinder block.
Pros and Cons of Material
The appearance of cinder blocks is directly related to the natural human desire for waste-free production. In the USSR in the postwar years, production developed at a rapid pace. Metallurgical plants literally grew into slag mountains. Then the decision came to use this waste to create building materials.
Slag served as a filler for the cement-sand mixture. The resulting mass was molded into large "bricks". The finished blocks were too heavy - weighed 25-28 kg. To reduce weight, voids were made in them. Hollow specimens turned out a little easier - from 18 to 23 kg with standard dimensions.
The name cinder blocks is used today, although not only slag is used as fillers, but also other components. In modern blocks you can find granite screenings or crushed stone, river gravel, glass break or expanded clay, volcanic mass. The production of cinder blocks is most often done by small businesses. Small private enterprises produce building blocks on vibratory machines, filling several forms at once with a cement mixture. After molding and ramming, the “bricks” gain strength for at least a month.
Cinder blocks are endowed with certain advantages and disadvantages.
- The advantage of block building material, first of all, is its low cost. That is why the material is in great demand.
- This building material has other positive characteristics. For example, blocks do not change their size after laying out. The structure will not shrink, which means that the design calculation will not be adjusted during the construction process.
- The strength and hardness of the "big brick" determine its service life. This is neither more nor less - as many as 100 years! Durability is not calculated, but time-tested. There are many buildings of the middle of the last century, "standing firmly on their feet." The houses did not squint or crumble, only the facades require redecoration.
- Blocks react poorly to ultraviolet and temperature changes. The material is not edible for rodents and insects.
- Due to the increased size, the construction is taking place at a fast pace. Masonry blocks are much less masonry than, for example, on a brick wall of the same size.
- Behind a cinder block wall, street noises are not audible, because it is capable of absorbing sounds.
- Finally, in the presence of simple equipment and desire, blocks can be made at home, which will further reduce the cost of construction.
The disadvantages of building material are not less than the advantages.
These include the following characteristics.
- Ugly appearance.
- The difficulty of attaching to the walls due to voids in the body of the block.
- The need for cladding to make the building attractive and protect the building material from exposure to external moisture.
- Fragility. If it falls during operation, during transportation or loading, the unit may crack.
- High thermal conductivity. Without additional insulation, the structure does not retain heat well.
- Wide tolerance limits. Dimensions may vary significantly.
The dimensions of cinder blocks directly depend on their types.
Standard cinder blocks are products with the following parameters, measured in millimeters:
- length - 390;
- width - 190;
- height - 188.
Due to the small difference between the width and the height, both values are often assumed to be the same, equal to 190 mm.
Hollow and full-bodied products have similar dimensions. The former, as lighter, are used exclusively for masonry walls. The second can serve as a source material not only for walls, but also for foundations, columns or other structural elements of buildings, which are under the greatest load.
Semi blocks of slag are always hollow. Overall dimensions may differ only in thickness (width). The length is constant and remains equal to 390 mm, height - 188 mm.
Thicker half-blocks are 120 mm wide, and thinner - only 90 mm. The latter are sometimes called longitudinal slag blocks. The scope of the semi-blocks is internal walls, partitions.
There is a "giant" in the slag family - a building block increased in size. Its dimensions are 410x215x190 millimeters.
For the construction of any object (home, garage or other utility building) information is required on the number of cinder blocks. Extra building material is useless, and a deficiency can lead to downtime and additional costs for loading, transporting and unloading cinder block. In addition, different batches of even one manufacturer may differ slightly. What can we say about buying the missing blocks from another supplier!
Problems with the construction of the structure due to a lack of basic material will not be guaranteed if you first calculate the needs of cinder blocks with maximum accuracy. Of course, you will have to buy a larger quantity. Firstly, because you always need a stock. And secondly, the blocks are not sold individually. Manufacturers stack them on pallets and fasten them so that when delivered to the buyer, the goods do not break, and it is convenient to load them into vehicles.
If necessary, you can purchase material and individually. However, the lack of a secure mount is fraught with the presence of chips and even complete destruction. In order to calculate the need for building blocks, for example, for a house, you need to know the dimensions of this structure.
First of all, you need to remember the school curriculum, or rather, the definition of areas and volumes. The task is simple, accessible to everyone and does not require any engineering knowledge.
The number of cinder blocks required can be calculated in two ways.
- By volume. The volume of the walls of the building is determined, the number of bricks in 1 m3 is calculated. The volume of the building in cubic meters is multiplied by the number of blocks in one cube. It turns out the necessary amount of slag bricks for the whole house.
- By area. The area of the walls of the house is calculated. The number of blocks per 1 m2 of masonry is found. The area of the walls of the house is multiplied by the number of pieces of cinder blocks in one square meter.
If you need to calculate the number of building blocks per square meter, two sizes are taken into account: length (390 mm) and height (188 mm). We translate both quantities into meters and multiply each other: 0.39 mx 0.188 m = 0.07332 m2. Now we find out: how many cinder blocks per square meter. To do this, divide 1 m2 by 0.07332 m2. 1 m2 / 0.07332 m2 = 13.6 pieces.
Similar calculations are performed to determine the amount of building material in one cube. Only here all block sizes are involved - length, width and height. We calculate the volume of one cinder block, given its dimensions not in millimeters, but in meters. We get: 0.39 mx 0.188 mx 0.190 m = 0.0139308 m3. The number of bricks in 1 cube: 1 m3 / 0.0139308 m3 = 71.78 pieces.
Now you need to find the volume or area of all the walls of the house. When calculating these parameters, it is important not to forget to take into account all openings, including door and window. Therefore, each construction is preceded by the development of a project or at least a detailed plan with doors, windows, openings for laying various engineering communications.
Consider the calculation of the needs of the material on the house "volumetric" way.
- Let's say the house is planned to be built square, with a length of each wall of 10 meters. The height of a one-story building is 3 meters. The thickness of the outer walls is the thickness of one cinder block, that is 0.19 m.
- Find the volume of all the walls. We take two parallel walls equal in length to ten meters. The other two will be shorter in length by the thickness of the walls already taken into account: 10 m - 0.19 m - 0.19 m = 9.62 m. Volume of the first two walls: 2 (number of walls) x 10 m (wall length) x 3 m (wall height) x 0.19 m (wall thickness) = 11.4 m3.
- Let us calculate the volume of two “shortened” walls: 2 (number of walls) x 9.62 m (wall length) x 3 m (wall height) x 0.19 m (wall thickness) = 10.96 m3.
- Total volume: 11.4 m3 + 10.96 m3 = 22.36 m3.
- Suppose that the house has two doorways 2.1 m high and 1.2 m wide, as well as 5 windows with dimensions of 1.2 m x 1.4 m. We need to find the total volume of all the openings and subtract it from the previously obtained value.
The volume of doorways: 2 pcs. x 1.2 mx 2.1 mx 0.19 m = 0.9576 m3. The volume of window openings: 5 pcs. x 1.2 mx 1.4 mx 0.19 m = 1.596 m3.
The total volume of all openings in the walls: 0.9576 m3 + 1.596 m3 = 2.55 m3 (round up to two decimal places).
- By subtraction, we obtain the desired volume of cinder blocks: 22.36 m3 - 2.55 m3 = 19.81 m3.
- We find the number of blocks: 19.81 m3 x 71.78 pcs. = 1422 pcs. (rounded to the nearest integer).
- Considering that there are 60 pieces on a pallet of standard cinder blocks, you can get the number of pallets: 1422 pcs. / 60 pcs. = 23 pallets.
According to the same principle, the need for building material for internal walls is calculated. With other dimensions, for example, a different wall thickness, the calculated values need to be adjusted. It should be understood that the calculation gives an approximate number of cinder blocks, the fact almost always differs from the calculation in one direction or another, but not by much. The above calculation was performed without taking into account seams, which account for 8 to 10 mm and a margin of approximately 10-15% of the calculated value.
Information on the amount of necessary material is useful for determining material costs for the acquisition and construction, as well as for allocating territory for its storage.
For how to calculate how many cinder blocks in 1 m3, see the video below.