Over the years, the popularity of houses built from various wall masonry materials has not decreased. Molded stone walls continue to attract the attention of most developers. This wall material is non-combustible, durable, reliable, environmentally friendly and warm. At present, several types of wall materials are presented on the modern building materials market, differing in their physical, technical, operational and thermal characteristics. From what exactly it is best to build the walls of houses, what exactly you need to pay attention to when choosing a wall material and what their technical characteristics are the most important and will be discussed in this article.
It’s no secret that the main purpose of the external load-bearing walls of the house (enclosing structure) is the reliable protection of the internal space of the rooms from adverse external influences. The outer walls of buildings must provide acoustic and thermal comfort, maintain the necessary microclimate inside the building. The interior space of the house must be reliably protected from cold, wind, noise, precipitation and at the same time provide comfort and effectively retain heat. Along with this, the walls of the house must be durable and strong enough.
One of the main indicators of wall material, which largely affects the subsequent operating costs of maintaining a house, is an indicator of heat transfer resistance. It demonstrates the thermal insulation qualities of the wall. The higher this indicator, the better the wall material is able to retain heat inside the house. In Ukraine, the required value of heat transfer resistance of external walls during construction is prescribed by DBN V.2.6–31:2006 and directly depends on the climatic zone of the construction region. Heat transfer resistance of the wall for temperature zone I must be at least 2.8 m²•K/W, for II – at least 2.5 m²•K/W, for III – at least 2.2 m²•K/W, for IV – not less than 2.0 m²•K/W. It is best that when choosing a wall material, its heat transfer resistance is slightly higher than prescribed by the regulations, as this will allow you to significantly reduce the cost of air conditioning or heating your home.
In addition, the value of the heat transfer resistance of a single wall is affected not only by the thermal insulation properties of a particular material, but also by the thickness of all its layers. Changing the parameters of one of the layers of wall material will entail a change in the total resistance of the entire wall. If it is required to expand the useful internal area of the house by a couple of centimeters without changing its external dimensions, but while maintaining its design thermal insulation properties, then this can be done using project changes that relate to wall materials, of which the enclosing structure of the house directly consists. For these purposes, the architect may try to change (reduce) the thickness of the load-bearing walls that was proposed in the project, and instead use another wall material that has a lower thermal conductivity, in other words, choose a warmer material. The same can be done with a layer of heat-insulating material. These project changes will allow you to get a building envelope of less thickness, but with the same heat transfer resistance parameter.
So what is the best thing to build houses from?
Let’s dwell on each of the wall materials in more detail.
Ceramics. Ceramics is rightfully considered one of the best wall building materials: ceramic blocks and ceramic bricks.
High-quality clay is used as a raw material in the production of hollow ceramic blocks. Clays mined in various deposits can differ not only in the composition of their chemical elements, but also in physical and technical properties, which in turn also affects the appearance of the finished product. Some blocks may have a brown tint, others – yellow-brown, others – red, which is associated with different concentrations of sedimentary silt minerals in clays, which in no case can serve as an indicator of the physical and technical properties of the material, since clay is only one of many components, and the rest – a number of organic substances and sand. In addition, during the production of porous ceramic blocks, special additives are used in the form of wood flour or sawdust, which, during the heat treatment of blocks, burn out and form closed pores inside the material, which increase the thermal insulation characteristics of ceramic blocks. When molded blocks are fired, they acquire high frost resistance, strength and low water absorption.
The main advantages of ceramics include:
• high durability,
• resistance to high temperatures and fire,
• excellent storage capacity,
• high vapor permeability, which in turn provides a favorable microclimate inside the premises,
• excellent soundproof characteristics,
• rather high thermal insulation characteristics of porous ceramics,
• relatively low price.
Along with this, ceramics has a number of disadvantages:
• significant weight of individual structural elements,
• in solid blocks and bricks (in which there are no voids) low thermal insulation characteristics,
• when trimming, the need to use a special mechanical tool,
• high level of water absorption (exceptions are facing and clinker bricks.
Currently produced ceramic blocks can have the following dimensions:
- height – 21.5 or 23.8 cm,
- length – ranging from 23 to 38 cm,
- width (wall thickness) – ranging from 25 to 51 cm.
This range of block sizes is optimal in terms of the design requirements.
Walls having a small width (thickness) can withstand a fairly high load that can occur in the frame of a house during low-rise construction, but at the same time they cannot withstand large point loads. In addition, walls with a small width require additional insulation. The already wide walls built of ordinary (solid) ceramic bricks, after additional insulation, will become even thicker, which, without increasing the overall dimensions of the external walls of the house, will lead to a significant decrease in its usable area. In some cases, the external dimensions of the house may have restrictions that dictate the size of the site or the conditions for its development, they cannot be increased.
The main advantages of ceramics include:
• high durability,
• resistance to high temperatures and fire,
• excellent storage capacity,
• high vapor permeability, which in turn provides a favorable microclimate inside the premises,
• excellent soundproof characteristics,
• rather high thermal insulation characteristics of porous ceramics,
• relatively low price.
Along with this, ceramics has a number of disadvantages:
• significant weight of individual structural elements,
• in solid blocks and bricks (in which there are no voids) low thermal insulation characteristics,
• when trimming, the need to use a special mechanical tool,
• high level of water absorption (exceptions are facing and clinker bricks.
Currently produced ceramic blocks can have the following dimensions:
- height – 21.5 or 23.8 cm,
- length – ranging from 23 to 38 cm,
- width (wall thickness) – ranging from 25 to 51 cm.
This range of block sizes is optimal in terms of the design requirements.
Walls having a small width (thickness) can withstand a fairly high load that can occur in the frame of a house during low-rise construction, but at the same time they cannot withstand large point loads. In addition, walls with a small width require additional insulation. The already wide walls built of ordinary (solid) ceramic bricks, after additional insulation, will become even thicker, which, without increasing the overall dimensions of the external walls of the house, will lead to a significant decrease in its usable area. In some cases, the external dimensions of the house may have restrictions that dictate the size of the site or the conditions for its development, they cannot be increased.
The main advantages of ceramics include:
• high durability,
• resistance to high temperatures and fire,
• excellent storage capacity,
• high vapor permeability, which in turn provides a favorable microclimate inside the premises,
• excellent soundproof characteristics,
• rather high thermal insulation characteristics of porous ceramics,
• relatively low price. Along with this, ceramics has a number of disadvantages:
• significant weight of individual structural elements,
• in solid blocks and bricks (in which there are no voids) low thermal insulation characteristics,
• when trimming, the need to use a special mechanical tool,
• high level of water absorption (exceptions are facing and clinker bricks.
Currently produced ceramic blocks can have the following dimensions:
– height – 21.5 or 23.8 cm,
– length
– ranging from 23 to 38 cm,
– width (wall thickness)
– ranging from 25 to 51 cm.
This range of block sizes is optimal in terms of the design requirements.
Walls having a small width (thickness) can withstand a fairly high load that can occur in the frame of a house during low-rise construction, but at the same time they cannot withstand large point loads. In addition, walls with a small width require additional insulation. The already wide walls built of ordinary (solid) ceramic bricks, after additional insulation, will become even thicker, which, without increasing the overall dimensions of the external walls of the house, will lead to a significant decrease in its usable area. In some cases, the external dimensions of the house may have restrictions that dictate the size of the site or the conditions for its development, they cannot be increased.
Currently, on the market of porous ceramic blocks, you can find blocks that allow you to build load-bearing external walls that do not require additional insulation. In order for these walls to meet the regulatory requirements for thermal insulation (for various temperature zones of Ukraine), they must have a thickness of only 38 cm when laying on a heat-saving mortar or a thickness of 44 cm when performing masonry work using a traditional cement-lime mortar. When planning the construction of external walls, it is necessary to select the width of the blocks corresponding to the thickness of the future walls, since the location of the groove of the ridge connection on their surface dictates their method of laying in the wall, which cannot be changed in any case. In addition, the parallel arrangement of the slotted internal voids in the blocks along the length of the wall provides an order of magnitude better thermal insulation characteristics. Ceramic large-format blocks have a fairly flat horizontal surface and precise shape geometry, which allows laying on a thin layer (2-3 mm) of adhesive masonry mortar. During the masonry process, one should not forget about additional strengthening of the masonry under the openings (reinforcement of horizontal joints).
The modern construction market currently offers a wide range of hollow ceramic blocks, which differ not only in location, but also in the shape of internal voids (perforations), which have excellent thermal performance. This type of product is gradually replacing traditional ceramics from the market. Almost all manufacturers are consciously re-profiling their production for the production of this type of promising products. Recently, such hollow porous ceramic blocks have even begun to appear, the voids of which are filled with insulation (mineral wool). Such a wall material is able to perform two functions at once – to act as a durable structural material and at the same time have low thermal conductivity.
When developing a project for a future house, it should be borne in mind that the length of the walls of large-format porous ceramic blocks should be a multiple of the block sizes, which will minimize their trimming, and, therefore, significantly reduce the consumption of wall material and reduce labor costs for masonry work (no time and effort wasted on cutting blocks). In addition, the presence of a large number of non-standard (cut blocks) in the masonry significantly reduces the thermal insulation characteristics of the wall and its bearing capacity. It is best to fill in various kinds of “oversized” places with corner or additional prefabricated blocks. If, during the masonry process, there is an urgent need to reduce the overall dimensions of the block, then this must be done exclusively with the help of a special saw, and not if not with a hammer. This is due to the fact that when sawing, you can achieve a smooth edge and eliminate the possible formation of cracks on the surface of the blocks.
For comparison, the estimated cost of building materials for the construction of 1 m2 of a wall with a thickness of 38 cm is: from ordinary building (clay) bricks – from 161 UAH, from porous large-format blocks – from 250 UAH.
Cellular concrete. Recently, this building material has become increasingly popular in the construction of load-bearing walls. Products made of cellular concrete are not expensive, have excellent heat and sound insulation characteristics, are light in weight and are easy to process. What exactly needs to be paid attention to during construction work using cellular concrete products?
Aerated concrete blocks are made from raw materials, which include a large number of ingredients. Cement or cement with lime can be used as a binder, as a filler – finely crushed quartz sand (sometimes with the addition of ash, which gives the finished blocks an original gray tint), a blowing agent – aluminum paste or powder, as well as plasticizers and water. Depending on the proportions in which these components are added during the production process, finished products made of cellular concrete can have different densities and strengths, which directly depend on the porosity of the material. The prepared mixture after mixing and pre-treatment is poured into special molds, as a result of a chemical reaction, pore formation occurs in them, the mixture increases several times in volume. This foamed mixture, after its complete hardening, is cut into blocks by special machines and placed in an autoclave oven for baking at high temperature (180 – 190 ° C) and excess pressure in an environment of water vapor. In an autoclave oven, the material seizes, gaining the necessary strength, reliability and high frost resistance. This processing method completely eliminates shrinkage of the material, provides the block with high accuracy of linear dimensions, the correctness of the geometric shape and smoothness of the surface. It should be noted that the accuracy of manufacturing blocks directly depends on the equipment of the production line with the equipment with which the blocks are cut.
Some manufacturers produce blocks that have special profiled grips on the ends, which make it easier to carry the blocks during loading and unloading operations and during the laying process.
Among the main advantages of products made of cellular concrete, it is necessary to highlight:
• high thermal insulation characteristics,
• sufficient compressive strength, allowing the use of these blocks as a material for the construction of load-bearing walls in low-rise construction (up to 3 floors),
• special ease of processing (very easy to process even with a hand tool),
• high durability, frost resistance, fire resistance and strength,
• high vapor permeability of the material, allowing the walls to “breathe”, thanks to which an optimal microclimate is maintained indoors.
Along with this, cellular concrete products have some disadvantages:
• if we compare the accumulating and noise-insulating properties, then they are inferior to blocks made of porous ceramics,
• having high porosity, they are able to easily absorb moisture, as well as absorb it from the air (they require additional measures to protect the wall surface from moisture).
There is no doubt that the more modern and technologically equipped the equipment the manufacturer has, the better the physical and technical characteristics and appearance of the finished product. Currently, all manufacturers of cellular concrete blocks produce their products in strict accordance with the requirements of DSTU B V.2.7–137:2008. Produced blocks have the following linear dimensions: height – 20, 25, 28.8, 30, 37 cm, width – 20, 25, 30, 35, 40, 45, 50 cm, length – 40, 55, 58.8, 60 cm. for masonry of external walls, blocks having a width of 25 or 30 cm are used, which are able to provide optimal operational and technical characteristics of the house, can provide the required load-bearing capacity, excellent thermal insulation characteristics.
Depending on the density of the cellular concrete used in the manufacture of blocks, blocks of the following grades are distinguished – D350, D500, D600, D700. Blocks with a density of 350 kg/m3 (grade D350) have the highest thermal insulation properties, but at the same time have low strength. Blocks of the D700 brand (density 350 kg/m3), on the contrary, have the highest strength, but at the same time they have high thermal conductivity (cold) and a relatively high price. They are recommended to be used only in problem areas associated with increased load. One of the most popular are blocks of the D400 and D500 brands, which have an optimal ratio of strength, thermal conductivity and price.
When building a house, it is necessary to choose wall material of exactly the density grade indicated in the project documentation. Do not experiment with wall material, as this may affect both the thermal insulation properties of the wall and its bearing capacity.
In addition, when buying blocks, you need to pay special attention to such a parameter as the accuracy of linear dimensions. According to the current GOST 21520–89, all manufactured blocks are divided into three main categories according to the accuracy of linear dimensions:
• 1st category – provides for deviations of linear dimensions in height no more than 1 mm, in length and thickness – no more than 2 mm,
• 2nd category – deviations in height should be no more than 3 mm, in length and thickness – no more than 4 mm,
• 3rd – no more than 5 and 6 mm, respectively. Blocks of cellular concrete of the 1st category are designed for laying using a thin-layer adhesive mortar, and 2nd and 3rd categories – for laying on a thick layer of masonry mortar (heat-saving, cement-lime or cement). Blocks can have a side surface, both non-profiled (smooth, requiring filling with masonry mortar of vertical and horizontal joints), and with profiled ends (having special tongue-and-groove locks on the ends that do not require filling with mortar). When building walls using blocks of cellular concrete, the estimated cost of the material for erecting 1 m2 of wall is: with a wall thickness of 20 cm – from 130 UAH, with a wall thickness of 30 cm – from 180 UAH.
We wish you successful construction.