What should be the bearing wall of the house. The thickness of the brick wall. Calculation of wall thickness taking into account thermal conductivity
V.V. Gabrusenko
Design standards (SNiP II-22-81) allow to accept the minimum thickness of bearing stone walls for masonry of group I in the range from 1/20 to 1/25 of the floor height. With a floor height of up to 5 m, a brick wall with a thickness of only 250 mm (1 brick) fits into these restrictions, which designers use - especially often recently.
On the walls of your house more than at first glance. It is important to know what walls you have, for example, you need to drill them or make repairs. This guide will show you the different types of walls that you can find in your home. Almost all external walls are load-bearing, so any significant changes must be carefully planned. For example, entering a new doorway will require supporting the wall.
Solid walls are usually as thick as the length of one standard brick. On buildings of more than 2 floors, the lower walls can be “brick and half” or 345 mm thick. It will take a big load on the floors above. Solid walls are usually found in old houses, not in new ones. One of the main problems with a solid wall is that it provides less protection against elements. Water can leak through the wall and penetrate the house more easily than with the help of wall cavities.
In terms of formal requirements, designers act on a legitimate basis and vigorously resist when someone tries to obstruct their intentions.
Meanwhile, thin walls react most strongly to all kinds of deviations from design characteristics. Moreover, even those that are officially acceptable by the Norms of the rules for the production and acceptance of work (SNiP 3.03.01-87). Among them: the deviation of the walls by the displacement of the axes (10 mm), by the thickness (15 mm), by the deviation by one floor from the vertical (10 mm), by the displacement of the supports of the floor slabs in the plan (6 ... 8 mm), etc.
The wall of the cavity consists of two separate "leaves" with a small gap between them. Each of the two leaves will usually be only one brick thick. In modern homes, lightweight concrete blocks probably make up the inner sheet, as they are much cheaper and more heat efficient than bricks. Two sheets are held by wall ties to increase strength. The walls of the cavity as a whole provide much better insulation, since water cannot leak out so easily, and the air pocket acts as an additional insulating layer.
If you ever need to drill one or both sheets of a cavity wall, you need to be careful to avoid getting debris into the cavity as much as possible. This can form on a wall tie and form a bridge for moisture passing through the cavity and into the inner sheet.
What these deviations lead to, let us consider an example of an internal wall with a height of 3.5 m and a thickness of 250 mm made of brick of grade 100 on a mortar of grade 75, bearing the calculated load from the overlap of 10 kPa (slabs with a span of 6 m on both sides) and the weight of the overlying walls . The wall is designed for central compression. Its estimated bearing capacity, determined according to SNiP II-22-81, is 309 kN / m.
Internal partition of the building
You can usually tell by the thickness of the wall, which can be a couple of feet thick. Any changes may require additional permissions from local authorities. Internal walls may be a mixture of load-bearing and bearing. It is often difficult to tell the difference. Drywall or turning and plaster walls will not be load-bearing, while a solid wall that runs through the middle of the house, parallel to the floor board, may be load-bearing. If in doubt, seek professional advice.
Suppose that the lower wall is offset 10 mm to the left from the axis, and the upper wall is 10 mm to the right (figure). In addition, slabs are offset 6 mm to the right of the axis. That is, the overlap load N 1 \u003d 60 kN / m is applied with an eccentricity of 16 mm, and the load from the overlying wall N 2 - with an eccentricity of 20 mm, then the eccentricity of the resultant will be 19 mm. With this eccentricity, the bearing capacity of the wall will decrease to 264 kN / m, i.e. by 15%. And this is if there are only two deviations and provided that the deviations do not exceed the values \u200b\u200ballowed by the Norms.
The thickness of the bearing brick walls
Partitions are almost always built as a frame made of wood, covered with drywall and plaster. Old houses can have the same basic design, only with the replacement of drywall strips. Hollow in the middle, usually carry cables, etc. for lighting system. Partitions can usually be removed or doorways cut into them without affecting the stability of the house.
As with external solid walls, it will probably be 225 mm thick if it is a load-bearing wall or 100 mm thick if it has no weight. Sometimes the inner walls. Brick walls are probably the most common building elements in building a house in India. These walls form the basic units for creating the rooms that make up the house. Walls, in addition to space dividers, are also structural elements that transfer the roof load to the ground. Brick walls are built on stripes or raft bases that support the walls.
If we add here the asymmetric loading of the ceilings with a temporary load (on the right more than on the left) and the “tolerances” that builders allow themselves - thickening of horizontal joints, traditionally poor filling of vertical joints, poor quality dressing, curvature or inclination of the surface, “rejuvenation” of the solution, excessive the use of half timber, etc., etc., then the bearing capacity may decrease by at least 20 ... 30%. As a result, the wall overload will exceed 50 ... 60%, beyond which the irreversible process of destruction begins. This process does not always appear immediately, it happens - years after the completion of construction. Moreover, it should be borne in mind that the smaller the cross section (thickness) of the elements, the stronger the negative effect of overloads, since with a decrease in thickness the possibility of redistributing stresses within the cross section due to plastic deformations of the masonry decreases.
The walls are built of brick and mortar. They can also be designed with various structural qualities and thicknesses. First-class bricks are identified by their uniform color and sonorous sound upon impact. Bricks are equal in size and have smooth edges and surfaces. These bricks do not chip and have no cracks. When the bricks are dry, there is no salt residue. First-class bricks have a minimum crushing strength of kg.
The work of bricks of the second class is performed using bricks of the second class and cement mortar. These bricks also have the property of first-class bricks, but are not very regular or even have a shape. These bricks should not be used for load-bearing walls for more than two-story buildings. Bricks of the second class have a minimum crushing strength of kg per square meter.
If we add more uneven deformations of the bases (due to soaking of soils), fraught with turning the base of the foundation, “freezing” of the outer walls on the internal bearing walls, the formation of cracks and a decrease in stability, then we will not just talk about overloading, but about a sudden collapse.
Supporters of thin walls may argue that all this requires too much a combination of defects and adverse deviations. Let us answer them: the vast majority of accidents and disasters in construction occur precisely when several negative factors gather in one place and at the same time - in this case there are “too many” of them.
The second quality of bricks. Brick work of the third class. This type of brick work is done using third class bricks and cement mortar or alumina. The work of brick of the third class is not carried out in any government. Job. As a rule, this type of brick work is intended for temporary work in the private sector.
Cement mortar Cement mortar is a mixture of cement and sand with water. Cement is a binder that requires sand as a filler. This wet mortar mix is \u200b\u200bductile and binds the two materials when they dry. This means that one part of the cement is mixed with 2, 3 or 7 parts of sand.
findings
- The mixture should be made on a dry, clean, flat surface.
- The mixture must comply with the specifications.
- The mixture should be by volume.
The thickness of the bearing walls should be at least 1.5 bricks (380 mm). Walls with a thickness of 1 brick (250 mm) are allowed to be used only for single-storey or for the last floors of multi-storey buildings.
This requirement should be included in future Territorial standards for the design of building structures and buildings, the need for the development of which is long overdue. In the meantime, we can only recommend to designers to avoid the use of load-bearing walls with a thickness of less than 1.5 bricks.
Precautions for Mixing Cement Mortar The following steps should be taken carefully when mixing cement mortar materials. The amount of water should be such that the mixture can be easily distributed over bricks or applied to a vertical surface. Water in excess of the required amount can ruin the mixture, and it can reduce the strength of the masonry. The mixture should be used within half an hour after its preparation.
Brick is one of the oldest inventions of mankind. Water, sun and clay, combined with the enthusiasm of the first masters, created an artificial stone of amazing strength, reliability and durability.
For centuries, brick structures such as the Moscow Kremlin, the Winter and Smolny palaces, and the Peter and Paul Fortress survived. But they accounted for military hardships, and frosts, and floods and fires. But to this day there is no need to restore their brickwork.
Another reason is that the basics of this method may be hidden from view. The architect must be provided with a foundation plan that indicates where the foundation trenches should be dug. Stock trenches are dug after marking according to the principle of the central line on the site according to the architect's drawings. The size of the trench depends on the thickness of the walls and the bearing capacity of the soil. The base of the dug trench is pushed to harden the surface. A layer of cement concrete is laid on the pushed surface.
Today, when the market is crowded with construction miracles, brick is still in fashion, as before, it is number one building material. Its excellent bearing capacity allows it to withstand the walls of overload created by concrete, reinforced concrete, wooden floors of multi-storey structures.
At the same time, brick is inferior to many wall materials in terms of heat and sound protection. For example, when outside the window it is -30 ° (and this is not uncommon in Russia), the thickness of the outer walls of solid brick should be 64 cm. Whereas under the same climatic conditions, the thickness of the cobblestone walls is sufficient - 18 cm.
This is usually 6-8 inches. This base concrete layer must be cured so that it reaches the expected strength. Basic concrete layers or courses of bricks are laid to create a stepped foundation, which will help to distribute the load on a large surface of the foundation. Precautions for the construction of foundations from a brick wall.
The marking of the foundations must be absolutely accurate, since the location of the walls depends on these designations. Mixtures of brick, mortar and cement concrete must meet the requirements. Since the foundation is an expanded base for the distribution of the load that comes to it over a large area on the ground. The width of the base of the wall depends on whether the wall is a load-bearing wall, load-bearing wall, partition or sock wall.
- Trenches should not be dug during the rainy season.
- The width and depth of the trenches depends on loading conditions and soil.
As you know, the thickness of masonry is measured by the number of bricks laid along the thickness of the wall, and is a multiple of the standard brick parameters (6.5 x 12 x 25). Masonry of 12 cm is called masonry in half a brick, in 25 cm - in one brick, 38 cm - in one and a half bricks, 51 cm - in two bricks, 64 cm - in two and a half.
Brick work is an important part of construction work carried out using bricks and cement mortar. This is done with different quality bricks with different grout ratios as per requirement. Construction of cabinets using various materials: brick and wooden cabinets, only wooden cabinets, mesh cement and wood. Today, many options are available for building a cabinet. In this article, we will discuss all the material available for making a cabinet.
To get maximum ventilation and natural light in your home, make sure the building is properly oriented. The orientation of the building saves energy and provides a comfortable stay. This article talks about the various factors and benefits of building orientation.
However, the thickening of the brick walls significantly increases the load on the base of the building, which the construction budget cannot but suffer from. How to increase the thermal conductivity and insulating qualities of masonry without resorting to excessive weighting? What should be the thickness of a brick wall? Experts say that her choice depends on the purpose and location of the wall.
Door and window frames are the most important parts of your doors and windows. They are available in various sizes, heights, widths and shapes. Frames hold locks and hinges and support doors and windows to make it easy to close and open. Here is what you need to know about the different doors and window frames.
On page as well as contributions to vocabulary. Bearing load-bearing walls, fire protection requirements and internal firewall, requirements. Starting from 12, 5 cm mesh additions from 1 to 3 cm for the manufacture of mortar, a layer of bitumen sheet must be included in the height of the floor in unfinished dimensions. Be reviewed before the first row of blocks apply.
Internal partition of the building
However, this is not enough for good sound insulation. To prevent extraneous sounds from entering the house, you should resort to one of three methods:
- increase the thickness of the masonry;
- apply additional material with sound-absorbing properties;
- use the “on edge” masonry when the brick is laid on the edge, thereby achieving a wall thickness of about 7 cm. If the length of the thin partition exceeds one and a half meters, it should be reinforced with reinforced wire.
Internal load-bearing wall
Ways to increase heat engineering and insulation of brick buildings
Thus, economically produced sink heights. Ecology: The raw materials for brick production are loam and water, i.e. natural materials without the addition of chemical additives. Energy consumption for production is relatively small, removal without problems. Thus, the bricks in their original form have a good ecological balance. However, the assessment may need to consider filling material, which can lead to poor life cycle assessments.
The thickness of the internal load-bearing wall of the house is 25 cm, or one solid brick, can withstand any kind of load from the roof, floors and other structures. An exception to this rule is a brick wall on which floor slabs join. In this case, single-brick masonry is unlikely to be enough.
External load-bearing wall
How to calculate the consumption of material in the construction of brick walls of various thicknesses?
This serves to compensate for unevenness, so the first series can be created absolutely a lot - and fly - right. Waiting time: Experience has shown that most rules focused on changes in carcass shape in the first weeks and months are occurring. Accordingly, the waiting period before the plaster is recommended to avoid cracks.
In the same way, the masonry should be protected from frost and strong moisture. The construction of masonry with frozen building materials is not allowed. Top open masonry should be covered with plates or tarpaulins. Modern thin plates are offset in a thin layer with a thickness of 1 to 2 mm.
An external wall with a thickness of 25 cm will completely cope with the supporting mission. However, a full-bodied brick cannot cope with the conservation of heat without additional insulation. Otherwise, in winter, at low subzero temperatures, the walls begin to get wet.
The increase in wall thickness to 64 cm, as already mentioned, is expensive in all respects.
The use of hollow bricks in the masonry will optimize the situation. Laying is necessary with the formation of wells, voids and widened seams. In this case, the thickness of the brick wall will be reduced to 51 cm due to voids. With their help, its heat-conducting properties will also slightly decrease.
To achieve 100% thermal insulation, you can not do without wall insulation. It should be borne in mind that specialists do not advise insulating a brick wall from the inside of the room. This is done either outside or inside the wall.
The recommended thickness of the brick wall in this case and the type of insulation depend on the region of residence. The external wall can be insulated with light concrete mixture, expanded clay, expanded polystyrene, slag. In addition to effective heaters, warm solutions should be used - both masonry and plaster.
The result is a dense "three-layer cake", where:
- layer number 1 - the outer part of the wall is half a brick thick, that is, 12 cm;
- layer number 2 - insulation of the appropriate type and thickness;
- layer number 3 - the inner part of the wall of blocks or bricks 25 cm thick (to ensure load-bearing capacity).
This method of building a brick wall contains three benefits at once:
- reduction in material costs;
- reduction of pressure on the foundation;
- expanding the space of the living room by reducing the thickness of the walls.
Building's facade
Facade insulation will also help to increase the insulation and heat engineering of the brick structure. You can achieve this in the following ways:
- conventional insulation of the facade, followed by its cladding or plastering;
- arrangement of a ventilated facade using siding, lumber, heat-insulating panels, plaster, facing brick.
Having listened to the advice of specialists, you will build a brick house for neighbors for a sight for sore eyes and yourself for joy. It will not resemble a massive pile of brick. But at the same time it will become a reliable fortress for you - warm, calm, comfortable. In this house-fortress it will be possible to live, not to grieve for several decades or even longer.