What brick is needed for what and where to use

Recommendation points

• Classification and purpose
• Silicate and ceramic: what’s the difference
• Dimensions and tolerances
• Private and facing
• Insulation brick
• Refractory grades

In private construction, up to twenty brands of bricks are used, while very often this masonry material is used for other purposes. It’s time to dot the i’s: we will describe the scope of application of the most popular types of brick products.

Classification and purpose

Brick is an artificial masonry stone intended for the construction of vertical building structures. Accordingly, the purpose of the brick is entirely determined by the functions of the building structure and the technical requirements for it..

The most common brick is masonry or ordinary brick, designed for the construction of load-bearing walls, internal partitions and filling the enclosing structures in buildings based on a reinforced concrete frame. When laying load-bearing walls, the main requirement for bricks is density and high compressive strength. For internal partitions, density is also important, but with the aim of increasing thermal inertia. For the same purpose, solid brick can be used to fill frame structures, subject to additional facing with heat-insulating materials, although recently hollow masonry, characterized by lower thermal conductivity, has been used more often..

The second popular type of brick is intended for finishing facade work, the construction of fences and supports for auxiliary structures – fences, awnings, parapets and others. The most popular in civil construction are hollow and porous-hollow bricks, the volumetric weight of which can be up to 2.5 times lower than that of an ordinary brick. Also widespread are textured and chipped bricks, which, in addition to heat-saving properties, give the masonry a high aesthetic value. Special types of bricks – clinker and hyper-pressed, these stones are optimal for finishing the basement of the building due to their high hardness and impact resistance.

Drawing up a general classification of bricks is hampered by the lack of a unified marking system. All varieties are determined by GOST or TU, according to which the stone is produced, while each standard has its own requirements for volumetric weight, grade, dimensional tolerances. In addition, the brick has several standard sizes and can be made from various materials..

Silicate and ceramic: what’s the difference

There are two main types of bricks – ceramic and silicate. The first, as the name suggests, is made from certain types of clay by firing it, the second is made from a mixture of sand and lime with a number of additives. It is the initial raw materials and the manufacturing process that determine the quality of building stone: if the basis of hardening of ceramic bricks is the thermal mechanism of vitrification, then silicate hardens under the influence of chemical and hydration processes. Because of this, the production of ceramic bricks is more energy-intensive and, accordingly, more expensive, and silicate bricks, although somewhat cheaper, are prone to erosion in contact with moisture and atmospheric gases..

Both silicate and ceramic bricks meet most building requirements. However, there are some nuances, for example – the issue of colors. Silicate bricks can be colored in bulk with fade-resistant pigments, while the color of ceramic bricks depends on the composition of the clay mixture and the heat treatment mode. It is also important to note that ceramic bricks from different batches have very significant differences in color, which must be taken into account when purchasing material for facade cladding..

In general, ceramic bricks are stronger and more durable than silicate bricks, but in civil engineering this difference is often insignificant. Nevertheless, the reduced compressive strength of silicate stones must be taken into account when designing load-bearing structures, and it should also be remembered that silicate bricks, due to their low heat resistance, cannot be used in the construction of fire protection elements of a building. You should also be careful when using sand-lime bricks in outdoor masonry: it has a relatively high water absorption and, unlike ceramic stone, dries much more slowly.

Dimensions and tolerances

The main format of ordinary bricks used in construction is single, it is characterized by dimensions (HxWxD) 65x250x120. There are also double and one-and-a-half bricks, which differ from single bricks only in height – 88 and 138 mm, respectively. Increasing the height of the stone helps to speed up the construction process, however, it reduces the number of joints required to align and set the required eccentricity of the loads. Therefore, one-and-a-half bricks are used, as a rule, when erecting internal partitions and filling concrete frames, and double bricks are used mainly in external heat-insulating cladding..

There are also special types of bricks, the length of which is 288 mm and the width is 138 mm, but in construction, the need to use such a stone rarely arises. In addition, there are shaped bricks, the shape of which differs from a rectangular parallelepiped, for example, wedge-shaped bricks for laying arches, corner and eaves. In the range of facing bricks, additional elements are often found for the correct execution of masonry corners and abutments.

In the manufacture of bricks, there is a fairly strict control not only of the compressive strength, but also of the dimensions. So, the tolerance in length is no more than 4 mm, in width – no more than 3 mm, in height – no more than 3 mm for an ordinary and no more than 2 mm for facing. Also, according to GOST 530–2012, the maximum deviations of flatness and perpendicularity of the edges, as well as the presence of defects, are established. For facing bricks, chipping of edges and corners with a depth of more than 15 mm is not allowed, while small chips are acceptable, but only in an amount of no more than 2 pcs. For ordinary bricks, bumps with a depth of more than 15 mm are allowed in an amount of no more than 4 pieces, minor defects and cuts are not regulated. Brick that has not passed quality control is allowed on sale only under the guise of rubble – for the construction of irresponsible masonry or filling voids in prefabricated and precast-monolithic structures.

Private and facing

In the course of control tests, a brick is assigned an average density grade from 0.7 to 2.4, which corresponds to a density of 1 m³ bricks from 700 to 2400 kg. With a comparable density of silicate and ceramics, the average brick density is determined by its voidness. For example, for an ordinary brick, a voidness of no more than 13% is allowed, which corresponds to an average density of at least 2.0. This requirement is due to the required high compressive strength, so a brick with prefabricated voids is not suitable for laying load-bearing structures, but can be used for laying walls of one-story buildings with a sufficient design thickness.

A brick that has voids is considered a facing brick. Lightening of the brick is required to ensure self-supporting properties and reduce the weight of the cladding, for its more reliable bond with the load-bearing layer of the wall. The brick can contain up to 96 voids: round and square up to 20 mm wide, slot-like – up to 16 mm. In addition, higher requirements are imposed on facing bricks to maintain geometry and be free from defects. Some varieties have a chipped or textured poke and spoon surface, some varieties have polished facial surfaces and chamfers. Almost all facing bricks are ceramic.

Insulation brick

A separate parameter of facing bricks is thermal efficiency, which is determined by the average density indicator. It is believed that ordinary brick with an average density above 2.0 does not have an energy efficiency, from 1.4 it is only conditionally effective. Thermal efficiency is regulated for masonry materials with an average density of up to 1.4, it is this material that is used when performing thermal cladding of buildings. In terms of aesthetic properties, it corresponds to ordinary facing bricks, but inferior in physical and mechanical.

It is easy to see that the average density of 0.7 is very difficult to achieve only due to the voids formed during molding. In fact, most bricks with a bulk density of less than 1 t / m³ – these are porous products, the raw material of which includes sawdust that burns out during firing. This manufacturing process, for example, is typical for porous ceramic blocks, which are well suited for external thermal insulation cladding, but cannot serve as the main carrier material..

Refractory grades

In conclusion, we will tell you about special types of bricks that can withstand high temperatures and their cyclic changes. Such bricks are used for laying stoves, fireplaces, as well as heat-resistant screens in baths and fireproof partitions, capable of performing a load-bearing function at extremely high temperatures..

There are two types of refractory bricks – fireclay and dinas, which in the first approximation can be called analogs of ceramic and silicate. Fireclay bricks are made from certain types of clay that have been fired and finely cleaned. Dinas bricks are quartzite flour baked after mixing with milk of lime. The latter variety is more suitable for lining fireboxes due to its increased heat resistance, but such a brick does not have sufficient aesthetic value. In addition, dinas refractories are much less common than fireclay.