Foundation for self-supporting walls. Scheme of a strip foundation for a house, preparation and marking
Those who have decided to start construction or carry out redevelopment in an already erected building should know what a load-bearing wall is and the dangers of its destruction. The purpose of a load-bearing wall is the ability to take on loads from other parts of the building, floors and roof. In order not to face the danger of destruction of the building, before starting work you need to determine which walls are load-bearing and carry out all the planned activities without touching these structures.
What's the difference
Walls are the main structural part of a building, but not all of them are able to withstand the load coming from the floors and roof. For this purpose, each building is equipped with load-bearing walls. Partitions that can only withstand the load of their own weight help to divide the space in a built house. Such walls are called self-supporting. The purpose of each non-load-bearing wall is to serve as a space delimiter, if necessary, simply to highlight a separate room.
Simply put, load-bearing walls are structures on which something rests. In every building, load-bearing and non-load-bearing walls play important role, but if the load-bearing support is a reliable support, a high-quality frame of the building, then not load-bearing partition, which, if desired, can be demolished during redevelopment without causing damage to the building. All walls are divided into load-bearing, self-supporting and non-load-bearing. Already by the name it becomes clear which of them are built in order to take on the main load.
Such a partition can be erected from:
- bricks,
- aerated concrete.
As a self load-bearing walls V panel houses installing monolithic slabs. Such curtain walls can be used to create additional passage by cutting openings into them and installing doors.
Correctly recognizing which walls are load-bearing means successfully carrying out redevelopment without violating building codes and regulations, without risking creating a situation the end result of which will be the destruction of the building. , which means changing the distribution of the load, and this will lead to skewing of the building, collapse of the ceiling and cracking of the remaining permanent structures.
They ensure the safety of not only the apartment in which renovation is underway or redevelopment is planned. The safety of dwellings located on the lower floors. The main difference between load-bearing structures and self-supporting ones is. Knowing the differences is not enough; you need to be able to correctly determine which wall is load-bearing.
It is necessary to know exactly which walls can be demolished during redevelopment and which should remain intact, at what thickness it is permissible to make an opening in the wall, and when it is too dangerous to carry out such work.
There are certain requirements, which I present to load-bearing walls:
- Strength and stability.
- Compliance with all fire safety standards.
- High level of heat, hydro, sound insulation.
Another feature of the load-bearing wall, due to which such structures differ, is the uniform distribution of the horizontal load exerted by the floor slabs. An important criterion strength, reliability and stability is the thickness of the load-bearing wall. This value is set for brick, monolithic and panel interior walls.
Strict adherence to established standards makes it easier to determine the load-bearing wall in any building or room.
Definition
Having learned what a load-bearing wall is, you can understand how important it is to build this structure in strict accordance with all existing standards and rules. Such walls are a natural continuation of the building itself, the beginning of which is the foundation. To avoid great difficulties and troubles in the process of redevelopment, you need to know how to determine the load-bearing wall in an apartment. In most cases, it is enough to carefully study technical documentation and determine the location of load-bearing walls on the building plan. However, it happens that there is no plan and you have to independently determine the quality and purpose of the erected structures.
The peculiarity of the construction of panel buildings is that in monolithic house as supporting structure reinforced concrete panels are used. Their thickness ranges from 100 to 200 mm. Structures made of gypsum concrete panels act as interior partitions, and their thickness does not exceed 80-100 mm. Thus, by measuring the thickness of the wall, you can recognize the load-bearing wall, the demolition of which in such a building is strictly prohibited. Non-compliance established rules will lead to inevitable deflection and collapse of the ceiling.
One of the most important indicators is the thickness of load-bearing walls in brick houses. To distinguish a load-bearing wall, you need to know its thickness, but it is better to have a construction plan on which all load-bearing structures are marked. Self-supporting walls in an apartment, as a rule, are much thinner than permanent structures. The thickness of the walls that bear the load from their own weight varies from 5 cm to 400 mm. Such a partition can be built from plasterboard, but more often it is a wall built from brick (half-brick masonry).
An experienced craftsman will tell you how to find out whether a brick house is a load-bearing wall or not, but the size of the structure will also help you understand this. Its peculiarity lies in the fact that the thickness of a brick wall is a multiple of this parameter of the brick, plus the thickness of the adhesion layer and finishing material. Thus, it is possible to find out which wall is in front of the builders. The thickness of the partition does not exceed 380 mm, and for a load-bearing wall this size is the minimum. The maximum thickness of a load-bearing wall in a brick house reaches 640 mm. The peculiarity of this structure is that an opening can be made in such walls. This is justified by the possibility of providing additional reinforcement to maintain uniform distribution of horizontal loads.
Their parameters will help you distinguish which walls can be demolished and which are strictly prohibited:
- from 80 to 380 mm - interior partition, which can be demolished if necessary;
- from 380 to 510 mm - internal load-bearing wall, subject to demolition subject to high-quality strengthening;
- from 510 to 640 mm - external load-bearing wall.
Brick houses or built according to a constructive plan, distinctive feature which is the presence of 3 longitudinal load-bearing walls (on the plan green) and transverse walls called stiffening diaphragms (highlighted in blue).
Owners of apartments whose windows faced the front side of the house had the opportunity to build an extension or even make additional window. You can get more detailed answers to all existing questions by watching the video.
When starting to carry out work on home redevelopment, you need to carefully study the apartment plan, which indicates the dimensions and purpose of the walls; if there is no opportunity to familiarize yourself with the documentation, then you should not make responsible decisions without measuring the thickness of the walls.
In the previous article, I talked about how to correctly calculate the foundation for a brick house, but today we’ll look at diagram of the foundation itself and determine under which walls it is needed. Also, in this article, I will talk about how to prepare the site and correctly mark all the walls under which concrete will be poured.
We have already figured out which foundation for a brick house is better, and, in our case, the choice fell on the strip one, but in order not to repeat ourselves, we will immediately proceed to the scheme.
Foundation diagram for a brick house
In order to decide on a scheme strip foundation, let's take a look at the layout of the rooms in the house.
As we can see, there are a lot of walls in the house, and pouring a monolithic reinforced concrete strip under each of them is impractical, since in this case, the cost of the foundation will at least double.
In most cases, it is sufficient to construct a foundation only under load-bearing and heavy walls. And thin and relatively light partitions can be erected on a rough concrete (reinforced concrete) floor.
Load-bearing and self-supporting walls
Now let's take a look at the diagram of the foundation itself, and then I will explain on what principle the internal load-bearing walls were chosen.
Bearers walls No. 1 and No. 2 designed to more evenly transfer the load from the roof to the foundation. Their additional purpose is to prevent significant “sagging” of wooden ceiling beams, since there is a very large distance between the opposite external walls.
The diagram below shows how the ceiling will be located wooden beams, on which the entire roof will rest.
In this regard, these walls will be at least 20 - 25cm thick, which means they will already have a relatively large weight. In addition, the roof will still rest on them, and the lack of a foundation under such walls is fraught with consequences.
Wall No. 3 separates the garage from the main house. No matter how well the garage is heated, it doesn't matter winter period, this will be the coldest room in the house due to the constantly opening gate.
So, in connection with the above, in order to retain heat in the house, it was decided to make this wall thicker, the same as all the external walls. Although it will be practically self-supporting, it will still have significant weight, which implies the presence of a sufficient foundation under it.
The remaining walls separating rooms and other rooms from each other can be made into thin partitions, the load from which can be easily withstood by a reinforced concrete floor poured onto the ground. In other words, the foundation under self-supporting thin partitions will not be poured.
Foundation thickness under load-bearing walls
In the previous article, in which we calculated the foundation for a brick house, I said that the entire monolithic reinforced concrete strip will be 40 cm thick, despite the fact that the total thickness of the external walls will be about 50 cm.
Below in the diagram you can see how a wall 50 cm wide will be placed on a base 38 cm wide. (Read in the previous article why the foundation is 40 cm and the base is 38 cm).
The diagram is quite approximate and, accordingly, does not respect proportions. Parameters such as thickness sand cushion, monolithic thickness reinforced concrete slab etc. - we will look at it later, in the relevant topics.
Since a rough reinforced concrete floor will be immediately poured on top of the base, there will be no “sagging” of the wall, and for strength and support on the ground, a foundation base of 40 cm will be sufficient. This will save on the foundation.
Site preparation and foundation marking
Your main enemy in the process of marking the foundation is grass and uneven ground, which is responsible for most of the errors in measurements. Therefore, before marking, the future construction site was cleared of tall vegetation (grass, bushes, etc.). In most cases, to clean and prepare the area, it is enough to use a trimmer (gasoline or electric scythe).
There was no need to level anything, since construction site and so it turned out, more or less even.
Of course, some time and effort were spent on cleaning, but this made it possible to more accurately mark the foundation and subsequently made the work much easier and faster.
It is worth adding that in our region the cleanliness of sites is monitored, and abandoned and overgrown ones entail a significant fine to the owner.
Marking strip foundation
The markings were made using a tape measure, a cord, pegs made from d8mm reinforcement, and a hammer, with which these same pegs were driven in.
First of all, we determine the location of the house on the site. Schematically it looks like this:
Before marking the location of the house on the site, carefully study the documents permitting construction. The basic rules for locating the house, regarding the red line and neighboring plots should be spelled out there. The diagram has a red line at the bottom.
Now, you need to mark the rectangular perimeter of the entire house. Below in the diagram, the perimeter is indicated by red dots.
Only after this can you begin marking the foundation. Now you have something to start from and marking all the walls will not be difficult.
The procedure and technology for accurately marking the foundation for a house, without the use of expensive tools and devices, is very simple and described in detail in one of the previous articles. In our case, it was produced in exactly the same way, so we will not dwell on this.
After accurately marking the perimeter of the house, checking that the sizes of the diagonals match, we marked everything external walls, and then internal ones. Thus, everything was ready for the next stage of construction of our future home.
It is worth adding that the marking was done by two people for about 2 hours, since the house is huge with a lot of corners. By the way, marking can be done by one person, but it is quite long and difficult to do accurately.
Well, that’s basically all there is to it house foundation diagrams, as well as everyone preparatory work. Well, in the next article we will proceed directly to the construction of the foundation itself brick house.
9. Walls of civil buildings. Basic requirements. External and interior walls, load-bearing, self-supporting and non-load-bearing walls, partitions.
Walls- These are vertical fences that separate rooms from the external environment and from each other. The walls must withstand the loads placed on them, ensure a constant temperature in the room and make it soundproof. In construction, depending on their purpose, walls are classified into external and internal. Depending on the material used, walls are made of artificial materials (concrete, brick, asbestos-cement) and natural (limestone, shell rock, tuff, wood). Depending on the perception of loads from the building, the walls can be self-supporting, self-supporting And non-structural. Bearers walls take loads from other parts of the building (floors, roofs) and, together with their own weight, transfer them to the foundations. Self-supporting the walls rest on foundations, but carry the load only from their own weight. Non-load bearing(curtain) walls are fences that rest on each floor on other elements of the building (frame) and support their own mass within one floor.
The walls of civil buildings must meet the following requirements: be strong and stable; have durability corresponding to the class of the building; correspond to the degree of fire resistance of the building; be an energy-saving element of the building; have heat transfer resistance in accordance with thermal engineering standards, while ensuring the necessary temperature and humidity comfort in the premises; have sufficient soundproofing properties; have a design that meets modern methods of constructing wall structures; types of walls must be economically justified based on the given architectural and artistic solution, and meet the capabilities of the customer; material intensity (material consumption) should be as minimal as possible, since this greatly helps to reduce labor costs for the construction of walls and general expenses for construction.
Partitions are called relatively thin walls that serve to divide the internal space within one floor into separate rooms. The partitions rest on the floors on each floor and do not carry any load other than their own weight.
PARTITIONS. Partitions must be soundproof, nailable, durable, and stable. Partitions are installed on the floor structure before flooring is laid. In places where partitions made of combustible materials adjoin stoves and chimneys, brick cuts should be arranged along the entire height so that the distance from the partition to the inner surface of the stove or chimney is at least 40 cm. FRAME. GYPSUM PARTITIONS. BRICK PARTITIONS. Brick partitions are laid 1/2 brick thick (12 cm). The basis for partitions can be concrete preparation under ground floor floors or reinforced concrete floors. Due to their significant weight, brick partitions should not be used on wooden floors. A non-load-bearing wall, or partition, can only be internal.
When constructing houses, both multi-storey and private country houses, load-bearing or self-supporting walls can be erected. The first type of enclosing structures experiences serious loads from the floors and roof. Self-supporting walls are vertical elements of a building on which nothing rests. During the operation of the house, loads in such structures arise only from their own weight.
What are they?
Basic distinctive feature Self-supporting walls, in comparison with loaded ones, is that they have a small thickness. Accordingly, less material is used during their construction. The thickness of the walls of this type, depending on what they were built from, can range from 50-380 mm.
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During the construction of the rear, among other things, non-load-bearing enclosing structures can also be assembled. Such walls also do not take the load from the elements of the house located above. In another way, structures of this type are called hinged. They are always built within the same floor. However, if their height exceeds 6 m, they can already be considered self-supporting. Their design and calculations are carried out accordingly.
Self-supporting walls are basically only external enclosing structures. Such elements of the building simply protect it interior spaces from wind and precipitation, adjacent to the main frame. Ceilings to such walls are attached to the side on all floors in height. When building houses, both single-layer and multi-layer self-supporting enclosing structures can be erected. If walls of this type are located inside the building, they only serve as partitions.
Features of operation
According to SNiP standards, in such structures when performing redevelopment in multi-story and country houses it is allowed to make openings or expand them to the required parameters. Also, walls of this type, in some cases, can even be dismantled and rebuilt without the risk of collapse of other building structures.
Calculation
Before starting the construction of any house, of course, a detailed design is drawn up. At the same time, such an operation as the calculation of self-supporting, non-load-bearing and loaded walls for stability is also performed. For brick structures, for example, such calculations are made taking into account data from several tables from paragraphs 6.16-6.20 of SNiP II-22-81. In any case, when calculating the stability of a self-supporting wall, the compliance of the ratio of its thickness to height with a given geometry with standard values is determined.
Features of construction
It is possible to build such enclosing structures from almost any materials. Self-supporting walls are elements of a building that can be constructed from wood, brick, or blocks. In any case, such structures are assembled exclusively on strong supports. Their foundations are poured simultaneously with the foundation of the building itself.
Self-supporting brick, block walls, etc. are mated with other types of enclosing structures exclusively using flexible connections. When using rigid ones, due to unequal degrees of loading, building elements may subsequently crack and become deformed. Accordingly, living in the house will become unsafe.
Self-supporting walls are structures that, when laid with bricks or blocks, are required to be reinforced according to standards. However, such enclosing parts of buildings are usually strengthened not as thoroughly as loaded ones. When constructing walls of this type, rods are inserted through a larger number of rows of masonry. According to the standards, reinforcement for such structures can be used with a diameter of 1-2 mm.
Materials for multi-storey buildings
When constructing high-rise buildings, self-supporting external walls can be constructed from:
- hollow, porous, solid ceramic bricks;
- sand-lime brick.
When constructing buildings that are not too high, sometimes blocks are also used:
- arbolite;
- ceramic;
- made of foam or aerated concrete;
- expanded clay concrete and any other large format.
A feature of such materials in comparison, for example, with the same brick, is a relatively low degree of strength. Therefore, their standards allow the use of them, depending on the type, when constructing houses no more than 3-5 floors high.
They call it walls structural elements buildings that serve to separate a room from the outside space (exterior walls) or one room from another (interior walls).
According to the nature of the work, walls are divided into: load-bearing, self-supporting and mounted .
Load-bearing walls perceive the load from their own weight and other structures and transfer it to the foundations.
Self-supporting walls carry the load only from their own weight along their entire height and transfer it to the foundations.
Curtain walls walls are fences that rest on each floor on other elements of the building (frame) and only support their own mass within one floor.
They are presented to the walls the following requirements: they must have sufficient strength and stability, have the necessary heat and sound insulating properties, be fire-resistant, durable and economical. Sound insulation requirements apply mainly to the walls of residential buildings.
Optimal thickness walls must be no less than the limit determined by static and thermal calculations.
Since January 1997, Amendments to SNiP 11-3-79 “Building Heat Engineering” came into force: the required heat transfer resistance for residential premises has been doubled, and since 2000 it has been increased by 3.45 times. If you follow the letter of the law, then brick walls should be built with a thickness of 1.5 meters, so it is advisable to use combined structures of external walls: load-bearing part of the wall, minimum thickness, plus effective insulation and decorative finishing.
Depending on the type of material, the walls can be stone, wood, or combined (of the “sandwich” type). Stone walls According to their design and method of construction, they are divided into masonry, monolithic and large-panel walls. Combined walls - various panel-frame houses.
Masonry is a structure made of individual wall stones, the seams between which are filled with masonry mortars. To create a strong monolithic system, rows of masonry are made with non-coinciding vertical seams, that is, with their bandaging.
Monolithic wall. The wall structure consists of a reinforcement frame and concrete. To pour concrete, you need to set up the formwork. The formwork can be removable or permanent.
Panel-frame Houses. Panel houses As a rule, they are manufactured in factories and assembled at the customer’s site. Panel materials: core insulation (expanded polystyrene or mineral wool), “clad” on both sides with LSU or OSB sheets.
Frame houses . Such houses have many options (manufactured in a factory or built on the site).
Load-bearing walls are erected in buildings without frames or with an incomplete frame. They are made of brick, small and large blocks. Performing both load-bearing and enclosing functions, such walls absorb loads from the roof, ceilings, wind forces and sometimes loads from handling equipment. Load-bearing walls rest on foundations. Self-supporting walls carry their own weight within the entire height of the building and transfer it to the foundation beams. Wind loads, affecting the walls, is perceived by the building frame or half-timbered frame. The wall filling is connected to the frame with flexible or sliding anchors that do not interfere with the settlement of the walls. The height of self-supporting walls is limited depending on the strength of the material and the thickness of the wall, the pitch of wall columns, the magnitude of the wind load, etc. Self-supporting walls are made of brick, blocks or panels.
Non-load-bearing (curtain) walls perform mainly enclosing functions. Their mass is completely transferred to the columns of the frame and half-timbering, with the exception of the lower sill tier, which rests on the foundation beams. Columns support mass curtain walls through strapping beams, half-timbered crossbars or supporting steel tables.
Lightweight curtain walls without being load-bearing structure, have one purpose - to protect premises from atmospheric influences. Application effective insulation materials and thin sheet cladding allows the low weight of curtain walls to ensure their high heat-shielding properties, and their manufacture without wet processes ensures satisfactory humidity conditions in the premises from the first days of operation of the buildings.
Curtain walls made of frame panels two floors high were used in the building of the Institute of Scientific and Technical Information in Kyiv. The frame of the panels, measuring 2.8X7.2 m, is made of extruded aluminum profiles, the glazing is made of double-glazed windows. The blind areas of the panels are lined with stemalite on the outside, and on the inside - particle board. Semi-rigid mineral wool slabs are used as insulation. The joints between the panels are filled mineral wool and covered with aluminum protective and decorative elements.
The thickness of the walls with insulation made of foam glass, semi-rigid mineral wool slabs, phenolic-resol foam FRP-1 is approximately 100-120 mm, which makes it possible to reduce the cubic capacity of the building (without changing the area of the premises) and, accordingly, the consumption of materials. All other things being equal, this helps reduce the cost of 1 m 2 of buildings.
In buildings erected in the Far North, lightweight panels are mainly used, consisting of two outer aluminum sheets 0.8-1.5 mm thick, between which there is insulation (polystyrene foam PSB, PSB-S phenolic FRP-1, Vilares-5 or polyurethane PPU-ES, PPU-308, density 35-80 kg/m 3); such panels in most cases have framing ribs. In the conditions of the Far North, the use of lightweight panels sharply reduces their thickness to 150 mm, and therefore their weight (for comparison: the thickness of lightweight concrete walls reaches 600 mm, brick walls - 770 mm)
Wall panels dimensions 1.3x3.5 m and 1.3x4.5 m with cladding made of aluminum sheet 1.5 mm thick, with framing ribs that absorb lateral loads, baked plywood 10 mm thick and polyurethane foam insulation used in single-story residential buildings in the North.