Fireproof, durable, lightweight, and also quite affordable in terms of price – such a building material exists and is actively used for the construction of houses, garages and fences. Cinder blocks first appeared at the beginning of the last century, but the well-deserved popularity came to them only in the 70s. Today the cinder block is actively used in private construction, but this material cannot be called ideal. We deal with the issues of choosing a cinder block, its pros and cons, features of use, we learn to calculate the required amount of material, make the right choice and make a cinder block with our own hands.
# 1. Cinder block: production features
Slag concrete belongs to the category of lightweight concrete blocks. For the first time, such material became known at the beginning of the 20th century, when Nicholas II was building a garage in the Winter Palace. The cinder block then, however, was made on the basis of waste from burning coal – slag, hence the name. Since then, the production technology has changed somewhat, and the durability of the first cinder block buildings provided the material with sufficient popularity.
Today the cinder block is made on the basis of cement and sand, clay, lime or gypsum can be added, as well as various plasticizing additives. The filler is no longer slag, but crushed stone, granite screenings, expanded clay, broken bricks, perlite, cullet and sawdust. In terms of environmental friendliness and harmlessness to health, the best fillers are expanded clay, sawdust, crushed stone and shell rock. The production is carried out on vibroforming equipment.
If in the 70s, when the cinder block began to be actively used in construction, garages, sheds and other utility and utility rooms were erected from it, today the advantages of an inexpensive material make it possible to use it for the construction of houses and even industrial buildings.
# 2. The main characteristics of the cinder block
Cinder blocks are produced in the form of a parallelepiped without voids or with voids of various shapes and sizes. It is often possible to meet with the fact that the dimensions of the blocks are rounded to 200 * 200 * 400 mm, but the documents standardize the length from 380 to 410 mm (usually 390 mm), width and height from 180 to 210 mm (usually 190 mm).
In hollow blocks, voidness can vary from 28 to 40%. Usually two or three round holes are made, two, four or more rectangular holes. The more voids, the better the thermal insulation properties of the material, but the less its strength. The average thermal conductivity of the material is 0.27-0.65 W / m2. The use of certain materials is explained by the peculiarities of the building. The block weight ranges from 15 to 20 kg.
The frost resistance of the cinder block can differ significantly, the choice depends on the characteristics of the region. Blocks F15-30 (the number means the number of freeze / thaw cycles that the block goes through without losing basic performance) are suitable for warm regions, blocks with maximum frost resistance F50 are best used in areas with more difficult climates.
Strength is determined by grades from M35 to M125: for laying partitions, you can use cinder block M50 and M75, for arranging load-bearing walls – M100-M135, and M35 slag concrete is used only in combination with other load-bearing materials. Today, by the way, in addition to the construction of residential and utility rooms, the material is used for arranging ventilation ducts and even for paving sidewalks.
No. 3. Cinder block: pros and cons
Cinder block is a rather controversial material in terms of advantages and disadvantages, so it is far from suitable in all cases, but when planning to build a country house or garage, you should definitely consider the material as one of the alternatives.
The main advantages of the cinder block:
- resistance to fire, and this is one of the basic requirements for the house;
- low price. A minimum of funds will be spent on the construction of a cinder block – the material can compete for the title of the most budgetary;
- the large size of the blocks and their relative lightness allows for very fast construction. The relative ease of erecting walls from cinder block allows people who do not have much experience in this area to take on construction;
- the light weight of the blocks allows you to save on the construction of the foundation;
- a high degree of strength and reliability of a cinder block house;
- high durability, not less than 100 years;
- resistance to rodents and mold.
- low thermal insulation qualities, therefore, one cannot do without insulation. The exceptions are those cases if the premises will be used only in the summer (summer cottage), temporarily (barn) or not have heating (garage). For insulation, polystyrene foam is often used, but mineral wool is also suitable;
- unpresentable view – minus controversial. Firstly, most building materials are in any case additionally revetted, the only exception is wood. Secondly, today manufacturers have begun to offer cinder blocks in different colors and with a decorative surface. In any case, you can decorate the walls from cinder block with siding, decorative brick, plaster with painting or wood;
- the complexity of the work on laying communications and fixing heavy objects on the walls;
- high hygroscopicity of the material, therefore good waterproofing is required;
- the safety of the material directly depends on the name of the manufacturer, therefore, it is better to trust responsible and reputable companies.
Experts recommend building cinder block walls only in dry weather and not leaving the box at home without a roof for a long time. In addition, it is advisable to lay on a high foundation in order to reduce the negative effect of moisture. It is better not to overstretch with decorative coating.
No. 4. What to consider when choosing and transporting a cinder block?
When choosing a cinder block, consider the following points:
- it is important to find out from the seller the main characteristics of the material, including thermal conductivity, frost resistance and strength grade;
- it does not hurt to ask about the filler used. In principle, there is nothing dangerous in the composition of the cinder block. The only caveat is the use of screening granite, as this stone may have natural radioactivity. Background measurement will allow you to choose the safest option. For greater importance, you can ask the seller for quality certificates;
the integrity and observance of the geometry of the blocks indicate the high quality of the material. Several blocks can be inspected for chips, cracks, and deformations. It is necessary to make selective measurements and check the conformity of the dimensions of the faces;
- An easy way to check the quality is to manually try to stick a nail into the block surface. If possible, it is better to refuse to buy such a cinder block;
- if the material was made without using a vibrating machine, then there is no need to talk about high strength – it will not be possible to use it for the construction of residential premises.
The thickness of the masonry is determined by the characteristics of the local climate. It is better not to make a layer of mortar too thick, otherwise the heat resistance of the walls can be greatly reduced (the optimal seam is up to 1.5 cm).
It is better to transport the cinder block on pallets, it is better to store them under a canopy so that they do not absorb moisture harmful to them.
No. 5. Calculation of the number of cinder blocks
It is not difficult to calculate the required number of cinder blocks for building the walls of a house – it is important to know only the parameters of the building being erected and the size of the blocks. Let’s take a block of standard dimensions 390 * 188 * 190 mm as a basis:
- if you build a wall half a block thick (190 mm), then the lateral surface area will be 0.39 * 0.188 = 0.073 m2. For 1 m2 of wall, 1 / 0.073 = 13.7 blocks will be needed. If we take into account the thickness of the seams in 8-10 mm, then 13 blocks are needed per 1 m2. It remains only to know the area of the walls and multiply this value by the number of blocks. If you plan to lay in two layers, then the value is multiplied by 2;
- a similar calculation is carried out for laying with a thickness of one block (390 mm). In this case, the lateral surface area will be 0.188 * 0.19 = 0.0357 m2, and for 1 m2 – 1 / 0.0357 = 28. If we discard the thickness of the seam, then we can talk about 27 blocks per 1 m2.
To the resulting value add 10-15% for possible losses. The area of windows and doors can not be subtracted. When calculating, it is important to take into account how the blocks will be held together: mortar thickness – 5-10 mm (no more than 15 mm), glue thickness – 2-3 mm As a rule, 60 blocks are placed on one pallet. Having calculated the required amount of material, you will know how many cinder block pallets to order.
No. 6. Large producers of cinder blocks in Russia
The guarantee of the quality of the cinder block and the safety of the house built from it is the name of the manufacturer. It’s no secret that it is better to give preference to proven large companies, and we will focus on them:
- “Stroyindustriya” – a plant founded in Chelyabinsk in 2000, produces a lot of building materials, incl. cinder blocks in standard sizes and in an assortment of colors;
- Modern Stone is another Chelyabinsk company. Produces standard and partition blocks (120 and 90 mm thick) with different voids;
- Stroykomplekt Plus is a Stavropol enterprise that produces cinder blocks and sells a wide range of building materials. Produces wall and partition cinder blocks of varying degrees of voidness;
- Block Expert produces cinder blocks in Yekaterinburg and delivers them to many regions of the country. The only drawback is that only M75 blocks are produced in strength and with voids inside.
No. 7. DIY cinder block production
When a cinder block is needed in small quantities (building a shed or producing a missing amount of material), you can resort to the independent production of a cinder block, however, you cannot do without a vibrating table or vibrating machine.
At home, they usually use blast furnace slag, coarse sand and M400 cement. Each home craftsman chooses his own proportions, but the classic recipe is as follows: slag – 7 parts, sand and gravel – 2 parts each, cement – 1.5 parts, water – 1.5-3 parts. In addition to blast furnace slag, one can naturally use gravel, sawdust, perlite, and brick breakage. You can also add a plasticizer – 5 g per block. They take so much water that the solution combines well in a fist, but crumbles when it falls.
The resulting solution is poured into molds with a slide, rammed with vibration for 3-5 seconds. If the solution settles heavily, you need to add a new portion, lower the clamp and turn on vibration. After that, the block is removed from the mold and dries for 5-7 days, then it gains strength for about a month. You can, of course, produce cinder blocks in metal or wooden forms, but without vibration shaping, they will not be strong enough.
The cinder block captivates with its budget, durability, fire resistance and a host of other positive performance characteristics, but it did not become widespread (such as a gas block) due to some features, but it is definitely worth considering as a material for building a house or garage.