When erecting the walls of a building, one of the most important engineering tasks is the correct design of window and door openings. And to solve this problem we cannot do without such an element as a bar lintel.
In our article we will talk about the main types of jumpers, their markings according to GOST, and also describe installation features in different situations.
Beams for covering the top edge of window and door openings
Purpose of jumpers
In order to understand how important it is to correctly calculate the door lintel, you need to find out why it is needed at all. The finished opening appears to have a frame made of the same material, but if you look deeper, it becomes obvious that its upper part has additional reinforcement; it often looks like a transverse element extending deep into the masonry on the sides; this is the lintel. Its structure must be calculated at the very beginning of construction.
The functions of this element can hardly be underestimated; these include the following tasks:
- Strengthening the wall structure. Without reinforcement, the entire structure may collapse, since it will not be easy for it to withstand the colossal load if there is a void below, this is especially true for load-bearing walls.
- Formation of the opening. The lintel creates the opening itself, since it is essentially its upper part; in brick houses, it can even determine its final shape.
- Creating a foundation for further construction. Ceilings and an extension of the wall are installed on this structure.
If necessary, you can later change the shape of the opening, but it is important to consider the location of the lintel. In this case, it will be difficult to increase the height of the opening. When expanding, it will also be necessary to extend the strengthening in accordance with the new project.
Strengthening the wall structure is the main function of the doorway lintel
When building a house, it is equally important to strengthen the opening in the load-bearing walls of a panel, brick, block or wooden house. Various methods can be used for this purpose.
Types of window lintels
A lintel is a rectangular structure made primarily of reinforced concrete. It is mounted above window and door openings, as well as above openings where a door is not provided. This design serves to strengthen the nodes and evenly distribute the load on the wall. There are also jumpers made of wood and metal.
In buildings made of brick, as well as in “monolith-brick” projects, the presence of a lintel is mandatory according to SNiP. In panel structures, the jumper is already in the structure itself.
The lintel is needed to strengthen structural units (door openings, window openings, openings without purpose) and to uniformly distribute the load that is created by the wall or ceiling itself. The point is that the load is distributed along the edges of the reinforced concrete lintel. There are many ready-made options for products in sizes, concrete grades and other parameters, but you can also make them yourself.
To make a jumper you will need a certain tool and material, without which it cannot be made.
- Formwork. These are sheets made of durable material (chipboard, fiberboard), which serve as a kind of form for pouring concrete. Also, the formwork requires spacers to hold the sheets themselves, because simply nailing them to each other will not work - the concrete will squeeze out the formwork and will have to be dismantled. The formwork is set to a level, you can also use a plumb line, and if you have a level, the level will be extremely accurate, which is very important.
- Fittings. It consists of metal rods with stiffening ribs. Necessary to impart rigidity and elasticity to the reinforced concrete lintel. The reinforcement is installed after the formwork is installed, connected to each other, creating a reinforcing mesh. It is advisable to weld the extreme ends of the reinforcement to the wall (or rather, grab it) so that the reinforcement does not float when pouring.
- Concrete. The main component of all reinforced concrete products. Has many brands and classes. For the lintel, concrete of class B15, as well as grade M200, is suitable, but in cases of high-rise construction (from five floors), it is advisable to use grade M250.
If you make concrete yourself, you will need a concrete mixer. If it is not there, then the process of making concrete will be extremely long and inconvenient. In this case, you will need a bath or other structure that will allow you to mix the mixture being prepared.
Concrete consists of sand, water, cement and filler (gravel, crushed stone). Depending on what kind of concrete you want to get, the proportions of ingredients will differ. But there is one caveat: with this manufacturing method, the building should not be higher than two floors and should not be of a dacha type, since the concrete will be ordinary and not vibrated, which is not so good for the structure itself.
After 28 days, the concrete sets and the formwork can be dismantled. This is done using a crowbar or a hammer. Before this period, you should not tear down the formwork because the structure may float a little. It would seem that this is insignificant, but even a loss of half a centimeter can have a very serious impact on the structure, bringing it into an unsatisfactory technical condition.
Also, when checked by technical supervision, this violation may lead to the suspension of work until this malfunction is eliminated. Since, according to SNiP, concrete sets after 28 days, it is recommended to carry out work on concrete after this period, and technical supervision will not see a violation in this. This applies to all buildings and structures, including houses on individual projects (private houses).
Important: the lintel must be flush with the brickwork. It should not stick out in any direction, either on the facade or on the back side.
- If it sticks out, although everything was set according to a level or level, then this means that the formwork was poorly secured and floated. In this case, you need to check the level again (even with a level) and make sure that the jumper has not violated its geometry and has not lost its true, calculated dimensions. If all is well, then the small protrusion can either be hidden with insulation, or beaten off with a jackhammer (alternatively, cut off with a grinder and a concrete disc).
- If the projection of the jumper exceeds the tolerances, then it is better to dismantle such a jumper, otherwise this object may not be accepted until the violations are eliminated. And the dismantling of a lintel in a finished structure, and its dismantling almost immediately after its installation, has varying complexity of repair and restoration work.
Also, lintels can be used in the construction of third-party structures: gazebos, pavilions, tents, stairs (small), garages. The principle of their installation is almost no different from the installation of jumpers in residential buildings, except for the size of the structure. The main use of reinforced concrete products (in particular, lintels) are structures and buildings made of brick, stone, foam blocks, cinder blocks, aerated concrete and other materials with a stone base.
There is a type of brick lintel in brick buildings, as well as in block ones. It consists of a structure with steel guides into which bricks are laid according to all standards and technologies. In the absence of ready-made products, this type is the fastest and most inexpensive way to install a jumper.
Previously, a type of wooden lintel was also used, but only when constructing an entire house made of wood. The load-bearing capacity was not too great, but sufficient for two-story and three-story houses. It had to be secured with nails.
Taking into account our advice, you can independently calculate all the necessary product parameters and set them in accordance with GOST. If you have a concrete or aerated concrete area above the window, then it would be most practical to install plastic corner models.
Reinforcement must be carried out at least 1000 mm.
First of all, it is necessary to fill the structure using the corner method, and then drill and install the lintels. This will be the best solution.
Jumpers are divided according to several criteria: by material, by purpose, by manufacturing method, by heat resistance and frost resistance.
According to the manufacturing method, jumpers are either finished products, supplied from the factory, or cast-in-place (manufactured using the method described above). All finished products have special reinforcement loops or technological holes designed for their transportation and ease of installation. This also applies to other finished reinforced concrete products.
According to their intended purpose, the following products are distinguished:
- block (width up to 25 cm);
- slab (width from 25 cm);
- beam;
- façade
The most popular for installation in residential buildings are block-type lintels. They have a square cross-section of up to 25 cm. They are used as lintels both in residential and private construction, and in the special construction of auxiliary structures, even when constructing non-metal fences. Regarding the characteristics of these jumpers, it is worth noting that they are not afraid of either temperature or moisture. This is, first of all, the advantage of concrete. Bar-type lintels are used in buildings and structures of all types: brick, stone, block and wooden. The exception is metal structures, but there the jumpers are designed and calculated completely differently.
Slab lintels are designed for the same types of structures as block lintels. They are often used in monolithic structures, as they have great flexibility, which is necessary in such structures. The width of such lintels starts from 25 cm. A special feature is that one part has a special selection for laying additional floors, visually it is a quarter. Unlike timber lintels, they are also used in large industrial buildings with increased load on load-bearing walls.
Beam products are used to cover openings; the main difference from beam lintels is that there is a special recess at both ends for supporting floor slabs and covering slabs. In view of this factor, they are necessary for structures in which the windows go below the level of the top floor slab. Also, the beam lintel has a high frost resistance coefficient F100.
There are facade lintels that block the openings of facade walls when the masonry protrudes more than 25 cm. Due to the development of construction technologies and the variety of timber lintels, facade lintels are practically not used.
Ready-made lintels are installed using a building level, masonry mortar and a crane. There should be a recess in the opening for the lintel, where the solution is applied and the lintel is laid. Also, after laying it, it is usually leveled and left until the solution sets. After this, bricks or blocks are laid on the lintel. The exception is beam slabs, which themselves have a recess under the level of the floor slab; they must be set to the maximum level and the hinges must be cut off immediately, otherwise this may interfere with further installation of the floor slab.
The marking is an abbreviated information plate with the characteristics of any product. The grade of concrete is indicated by the index “M”, the reinforcement class is “A”, frost resistance is “F”. The jumpers themselves are designated by abbreviation:
- block lintels are designated as “PB”;
- slab – “PP”;
- “PG” means beams;
- “PF” is a façade lintel.
These abbreviations are followed by numerical values, where the cross-section number is indicated first, and the letter indices after it indicate the type. It is followed by a number that indicates the approximate length in dm. Then a hyphen is written, followed by a number that indicates the load-bearing capacity in kN/m.
There is also a small letter “p”, indicating the presence of mounting loops, and fitting outlets are also indicated, indicated by a small letter “a”.
There are also special reinforced concrete structures that can withstand loads from seismic activity, withstand the ingress of highly toxic and chemical substances, as well as radiation. Therefore, it is necessary to select a jumper based on both the technical specifications and many other factors that are usually prescribed in the project.
In addition to the type of reinforced concrete products, the size also affects the cost. Before you buy a lintel for openings (both window and door) of any brand, size, characteristics, you should pay attention to their technical condition. Large chips, cracks, and visible deformations are critical.
There are maximum permissible deviations, according to SNiP, but often this is rejected at the production stage by the factory and non-marketable products are sold at large discounts. If one supplier offers a price significantly lower than that of competitors, then the inspection and verification of the product must be very thorough, since it could be a fraudster who bought defective products and is trying to sell them.
After purchase, reinforced concrete products are transported to storage areas, usually to a construction site. The rules for storing lintels provide for the height of stored products to be up to 2 meters. It is also necessary to install a gasket between the rows to prevent chipping and other damage.
The installation of reinforced concrete lintels is carried out in accordance with current building codes and safety regulations, observing additional requirements. Remember that the load from the walls, especially load-bearing ones, is very high and if the technology is violated, this can lead to tragic and fatal consequences.
For the technology of installing window lintels during house construction, see the following video.
www.stroy-podskazka.ru
Main varieties
To construct the lintel, especially durable materials are used; they can be from the same category as the wall itself, or they can be radically different from the original structure. The main condition is to ensure the strengthening of the opening, as well as the uniform distribution of the applied load. All this will help to adjust further calculations for the structure in the wall.
In order to strengthen the opening in the load-bearing wall of a panel house or any other house, the following materials can be used:
Depending on the chosen option, the installation of lintels above the opening differs in technological terms. Brick structures should also be placed in a separate category; they should be considered in more detail.
The main types of lintels for strengthening a doorway
Lintels for openings - 4 options for private buildings
Lintels strengthen openings in the house
Are you building a house and don’t know how to strengthen window and door openings? Let's figure out what kind of jumpers exist, what are the pros and cons of each option, and how to properly lay out the elements when carrying out work.
Jumpers are installed both outside and inside buildings
We will analyze the following types of products:
- Reinforced concrete lintels;
- Monolithic structures;
- Metal elements;
- Wooden crafts.
Each option has pros and cons, so when choosing, consider all the nuances.
Reinforced concrete elements
Concrete lintels are very reliable and durable
This is the most popular and widespread option, which has a number of advantages:
- Strength. In the manufacture of reinforced concrete lintels, concrete grade M250 and a durable reinforcing frame are used. Thanks to this, the load-bearing capacity of the products is very high; they can withstand high loads without problems;
- Durability. Concrete withstands weather conditions well, the service life of products exceeds 50 years, but most often they last much longer;
- Low cost. The price of products, depending on the type and cross-section, can range from 250 to 4000 rubles per piece. The average cost is from one and a half to two thousand (data is current for spring 2022);
- A large assortment. There are so many options that you can easily choose the optimal solution for any opening.
Reinforced concrete lintels for brick walls are ideal
This option has one drawback - the elements are quite heavy, and if large lintels are needed, it will be difficult to lift them without lifting equipment.
Load-bearing reinforcements for large cross-section openings weigh quite a lot, and it is impossible to lift them without a crane
Let's look at the main types of products:
| Illustration | Description |
| Bar lintel - this includes all options up to 250 mm wide. The products are popular in private buildings as they are lightweight and can be installed by hand. If you need to lay an element with a width of 400-500 mm, then it is easier to take two lumber elements; they are much easier to install manually. | |
| Slab lintel - this includes all options with a width of more than 250 mm. In private buildings they are rarely used, since their installation requires the use of a crane. | |
| Beam lintels. They have a special quarter for support and are used where high load-bearing capacity is needed. In the private sector they are rarely used due to their large size. |
As for the dimensions, the calculation is made depending on the load on the elements. You must roughly calculate how much weight will press on the surface, and based on this, the height and width of the products are selected (this should be selected by a specialist builder).
The length depends on the type of structure, so the support of the lintels on the brick wall should be at least 250 mm on each side. And if jumpers are placed on partitions, then they should extend 200 mm.
To ensure strength, lintels must extend onto the walls by at least 250 mm
Monolithic elements
This option can be filled with your own hands.
This option is often used in the private sector and has the following features:
- Formwork is constructed over the opening. The instructions for carrying out the work are simple: the structure must extend onto the walls by at least 250 mm, the minimum height of the lintel is 200 mm, the width is usually equal to the thickness of the wall. For work, a durable board with a thickness of at least 40 mm is used;
The formwork must withstand the heavy weight of concrete
When assembling the formwork, use self-tapping screws; they hold the board together much better than nails.
- The reinforcement frame is assembled. In order for the lintels to be strong and withstand high loads, they should be reinforced with a reinforcement structure; the elements are connected with wire as shown in the photo;
The frame makes concrete lintels much stronger
- The reinforcement frame is laid in the formwork. The structure is exposed inside, after which lintels are nailed on top of the formwork for additional reliability;
Additional reinforcement at the top increases the reliability of the formwork
- Concrete is poured. For work, a composition of a grade no lower than M250 is used, it is aligned along the upper edge, after which it is necessary to allow the composition to gain strength. The formwork can be removed after 2 days, but the concrete must gain strength for at least a week.
For pouring you need concrete grade no lower than M250
In buildings made of aerated concrete, you can use special blocks with recesses or cut out cavities in conventional versions. Then a reinforcement frame is placed there and concrete is poured.
This is how you can strengthen openings in aerated concrete buildings
The advantage of this option is its simplicity and low cost, the disadvantage is that if you make mistakes, reliability will suffer.
Metal elements
Steel products are excellent lintels for openings
This option is great for window openings. Its main features are:
- High reliability. Steel has high strength, so it is excellent for strengthening surfaces above windows or doors;
- Many design options. For work, you can use corners, channels, strips and other elements. The main requirement is strength, and the configuration does not really matter;
Metal jumpers from corners - a simple and reliable solution
- Possibility of carrying out work without stopping. Unlike monolithic options, you don’t need to wait; you put corners or something else, and masonry is immediately done on top of them;
- Light weight. The metal weighs little and can be installed without assistance. This is a big advantage when doing the work yourself.
There are even special window lintels made of galvanized steel.
The only disadvantage we can highlight is the high thermal conductivity of the metal - such products conduct cold very well.
Wooden elements
This option is not used often, since the service life of wood is much shorter than that of brick or blocks. As for the advantages, they are as follows:
- Low cost. Wooden beams are inexpensive and can be purchased at almost any store. It is best suited as a budget option;
Wooden elements are durable, but their service life is short
- Light weight. You can install wooden lintels yourself;
- Easy to install. One or two beams with a cross-section of at least 200x200 mm are taken and laid in the opening with an overlap of 250 mm. They are fixed with anchor bolts, and all joints and seams are filled with cement mortar. The lower part, which rests on the walls, is waterproofed with two layers of roofing felt.
Wood beams require careful antiseptic treatment
Conclusion
Now you know what types of jumpers are available and what are the pros and cons of each option. The video in this article will reveal some of the nuances of the topic even better. If something is unclear to you, ask in the comments.
klademkirpich.ru
Brick
A brick lintel is used to create openings in a load-bearing wall in brick houses; it is usually used for small structures. A device of this type of construction is based on the use of a particularly strong mortar, as well as the introduction of metal rods or pipes into the masonry.
A distinctive feature of this type of construction is the ability to create spectacular arched vaults. In this case, the masonry consists of straight and wedge-like elements. The seams should be perpendicular to the exposed lower tier. All joints are tightly filled with mortar. In order for the arch to hold its shape until the solution dries completely, it is additionally reinforced with wooden spacers. This formwork is installed in advance.
In the shape of an arch, 2-3 rows are often erected. The position of each of them is determined according to a special template. To adjust individual elements, use a square and a cord. It is necessary to be equal to the center and the first row.
Brick lintel installation diagram
Process
The arrangement of lintels, with the formation of a unit and taking into account support in the wall, must take place according to the rules described in SNiPs. Since reinforced concrete lintels are used most often in modern buildings, the process of their installation consists of the following nuances:
- For laying, a ledge is made with a width of at least 25 cm, and on each side of the opening, the length of the structure should exceed this width by 50 cm.
- For installation, use a truck crane to lift the lintel - it will lift and lower it to the desired support point, onto which uncured concrete mortar has already been applied.
- With prefabricated options, formwork is arranged, formed along the width of the opening, a reinforcement cage is knitted and the lintels are poured in a monolithic manner, leaving them until completely dry.
Metal jumpers are lightweight. Presented in the form of channels and various forms of rolled steel, their advantage is that during operation they can be cut to the required length.
This option is also suitable when other types of lintels are categorically unsuitable for the wall of a particular opening, or a new one made from other materials cannot be installed (the old opening is expanded or a new one is cut out). Metal can bend, so supports are made to support them. In the rest of the process: concrete is poured, as with reinforced concrete.
Brick lintels are mounted to the main wall along the top of the opening , and then connected to each other using a shelf from which clamps hang, placed in vertical seams. The clamps reliably reinforce the lintel, and it turns out strong.
Experienced craftsmen choose longitudinal, wedge, beam or vaulted installation methods. Concrete mortar for laying is mixed in small portions so that it does not harden quickly.
Recently, in most cases, builders have placed the professional BAUT reinforcement system into brick lintels.
A simple and reliable way to install a brick lintel - in the video:
Reinforced concrete
To strengthen the opening in the load-bearing wall of a house, reinforced concrete lintels are most often used. A preliminary calculation allows us to determine which element will be most suitable in this case. Such reinforcement of the opening can be made directly on site using formwork, reinforcement and liquid concrete.
To speed up the process, already cast elements are most often used. In order to secure them in the load-bearing wall, it is additionally recommended to use reinforcement to strengthen the sides of the opening. In other words, the metal is laid on those areas that are in direct contact with the reinforced concrete part.
The main requirement in this case is compliance with the installation rules. The lintel must completely cover the opening and extend approximately 25 cm into the wall. The exact requirements are determined by the specific type of structure. For each type of lintel and its relationship with the width of the opening, special standards have been developed.
Jumpers above windows - how to install a reinforced concrete or brick connection (63 photos)
When building a house at a certain stage of construction, there will be a need to build a reinforced concrete lintel. Oddly enough, it is not at all difficult to make lintels over windows in a house yourself, and the work will be much more economical financially, since the costs will only go to purchasing materials for the work.
What is a reinforced concrete lintel
Most often, reinforced concrete lintels over window and door openings are divided into:
- non-load-bearing beams that can take loads from the wall above;
- load-bearing reinforced beams that take the slab load;
- large load-bearing part (purlin);
- a weakened thin bridge (pencil) used on weak partitions. Typically this type is used for doorways;
- a girder-shelf (crossbar) on which slabs or similar materials are placed.
Basic production of lintels over windows
To make a reinforced concrete lintel you will need a small set of tools:
- fittings;
- metal corners, a set of nails;
- boards;
- wire;
- And also cement, sand and crushed stone for mixing concrete mortar.
Before starting work, you should correctly select the desired type of jumper.
So, for small, lightweight structures, it is recommended to use the usual simple option (as shown in the photo of the lintels above the window), which will significantly save the family budget.
And the technology for manufacturing reinforced concrete window lintels is quite simple:
- The lintel is poured directly above the desired opening. But keep in mind that you will first have to prepare the formwork.
- The work takes place on the ground and is subsequently installed in place. The second option will add a little complexity to the work, since you will have to hire a crane to install the jumper in the right place.
DIY formwork for lintels
Before making a lintel over the window directly at the opening site, you will have to tinker with the formwork, which will have to reliably withstand a large load from concrete.
There is an option to create a form from wooden boards that will serve as a shield. It is better to take a board with a maximum thickness of 25 mm, which is fastened with self-tapping screws and a screwdriver. When the formwork is no longer needed, it can be easily removed by unscrewing the screws.
The first step is to install the shield horizontally in the opening, and it should rest against the support. Then a mesh of reinforcement is placed into the shield and secured with self-tapping screws.
For greater convenience and tension stability, experts recommend attaching the shield to the reinforcing mesh with special wire. This fastening will help the shield fit tightly and be accurately attached to the window opening.
We insulate a reinforced concrete lintel
It is no secret that the opening between the masonry and the lintel must be properly insulated. As a rule, insulation with a thickness of at least 100 mm is used. It is placed in the formwork opening and filled with concrete mortar.
Typically, mineral wool is used for insulation purposes. In this option, it is necessary to lay the window slopes (openings) using bricks so that the window itself rests against it. And for greater reliability, the structure should be secured using polyurethane foam.
A simpler way to insulate the lintel under the window is to use extruded polystyrene foam, which is known for its strength. It is better to take sheets 30 mm thick.
To securely fix the window in the opening, it is reasonable to pour polyurethane foam into the space formed between the frame and the insulation.
Rules for making jumpers
When creating a reinforced concrete lintel, it is necessary to strictly adhere to the described technology. There are also some nuances and rules in the work:
- For greater strength of the reinforced concrete belt, the diameter of the reinforcement mesh should be 14 mm.
- It is recommended to strictly adhere to the dimensions of the reinforced concrete lintel: the height should not be more than 1/20 of the length of the opening itself, and the width should correspond to the width of the wall (without indents).
- It is more reliable to use ready-made lintels, or to make your own formwork.
- Used formwork should be removed only after at least 25 days, for greater strength of the concrete solution.
- When pouring the solution into the formwork, you should compact it carefully to avoid voids.
- When making lintels, it is better if the window is quarter-length.
Making lintels for windows is a very simple process that you can easily do yourself. The main task is to calculate the necessary materials and prepare them.
If you follow all the rules and correctly carry out the work technology, you can get a reliable, strong and durable structure.
Photo of lintels above windows
landscapeportal.ru
Metal
Strengthening a window or doorway with concrete is possible only if the load-bearing wall is necessarily reinforced; some houses can be equipped with simpler metal structures. Such jumpers are most often presented in the form of an angle profile; they are made of durable metal that can withstand pressure and tension under enormous loads on it. With the help of such corners it is very convenient to build reinforcement in a brick wall.
In order to install such a part, it is necessary to fit it to the seams in the masonry. It is not necessary to reinforce the walls on the sides with reinforcement. In this case, it is enough to place the corner only 15-20 cm deep into the wall.
Prefabricated metal lintels can be used for almost any type of structure; they can be installed directly on the construction site, without making preliminary calculations.
The easiest way to strengthen a doorway is to use a metal lintel
Installation
Having become familiar with what lintels for aerated concrete are and the depth of support, let’s move on to the direct process of their installation.
Sequence of actions when installing aerated concrete U-blocks
Such beams are the most common recently, since the process of laying a finished factory product is quite simple. In addition, craftsmen manage to maintain the continuity of the masonry, while obtaining a perfectly flat surface. The technology is used to strengthen openings up to three meters, the work is as follows:
- Supports are made for the lintel so that it does not bend under the weight of concrete. To do this, a board is installed along the length of the upper masonry, which is supported by wooden blocks, bricks or metal pipes.
- The blocks are laid in such a way that the thick wall extends outward and the arrow points upward. For correct orientation we use markings. It is very convenient if the thickness of the beam corresponds to the thickness of the masonry, and its height coincides with the height of the block. If necessary, to build houses with thick walls, several beams can be laid simultaneously. A lift is used to lift products whose weight ranges from 100-200 kg.
- All seams are taped, including horizontal ones.
- The blocks are insulated on the outside with mineral wool or sheets of expanded polystyrene.
- A frame of reinforcement and fastening wire is installed above the opening. It is pre-coated with an anti-corrosion compound.
- M200 concrete is poured into the blocks to the level of their edges. We level and compact the composition.
- After the concrete has dried, remove the boards and supports.
When can construction continue? Only after the structure has completely hardened do we continue construction. The timing depends on what time of year the construction is taking place, weather conditions, temperature and humidity. In hot, dry weather, concrete needs to be watered until it is completely set.
Stages of work when reinforcing an opening with a monolithic concrete product
Pouring a concrete mixture is, as already mentioned, the cheapest way to arrange a future window. Follow the step-by-step instructions:
- We lay the block row, providing the necessary space on both sides of the opening.
- We install removable formwork from available materials (plywood, beams, etc.),
- We strengthen it every 50 cm with elements in the vertical and horizontal directions.
- We attach insulation to the outside of the wall.
- We install a frame made of reinforcement. For small structures it is possible to use steel reinforcing mesh.
- The formwork is filled with M200, M300 mortar.
- The composition should be compacted and leveled.
- We remove the formwork elements after the solution has dried.
Installation of jumpers from corners
Experts advise using metal corners to strengthen window structures up to 1.2 meters if the height of the subsequent masonry is at least two-thirds of the width of the opening. If this requirement is met, we proceed as follows:
- We cut out the grooves for the corners with an indentation from the edges of approximately 10-13 cm.
- We treat the metal structure with an anti-corrosion compound and wrap it with plaster mesh.
- Make sure that the product rests on the walls.
- We lay the corners on the inside and outside.
Along with this method, reinforcement is also successfully used to strengthen narrow openings. The use of aerated concrete or reinforced concrete beams in these cases is not justified. To reinforce one opening, four rods with a diameter of 10 mm are used. The rods are placed in the holes, which are then filled with glue or mortar. Blocks are then laid on the fixed rods.
Strengthening the opening is a process that requires certain knowledge and skills. To ensure the reliability and durability of the structure, it is important to correctly perform the calculations and consistently carry out the described actions.
Calculation of a lintel in a wall
Exact calculations are performed during the project preparation process. To do this, you need to take into account the specifics of the building material, the potential load exerted on the opening and the features of the structure itself. The main parameters in order to make the final calculation of the reinforcement of a doorway in a load-bearing wall are:
- strength: 1.12 * part strength * material strength;
- deflection: standard moment * design length of the jumper / (10 * moment of inertia * modulus of elasticity of the material) = 1/200;
- load, including from the top masonry and floors: thickness of the opening * width of the opening * height of the masonry * specific gravity of the material;
- moment of resistance: design load/8/design material resistance;
- moment of inertia: depth of support of the jumper * moment of inertia of the material * design length of the part / (10 * modulus of elasticity of the material).
Calculation of reinforced concrete lintel in the wall
All parameters necessary to perform the calculation should be found using formulas in a certain sequence. Data for some of them can be obtained by analyzing the properties of the materials used and design data for the opening and the house as a whole.
Based on these indicators, you can get the final result, which will show all the necessary parameters for arranging a lintel for the opening of the load-bearing wall of the house. If the standards are observed, the building will not sag and will be completely safe for its operation.
We recommend watching the video:
Filling jumpers
The photo shows how the formwork for the lintel is installed over a doorway measuring 800x2100 mm, the width of the interior wall is 200 mm, the minimum depth of the lintel support is 200 mm. Since the width of the board matches the width of the wall, there is no need to knock down the shields.
First, the height of the door is measured, taking into account the space for foaming and slopes. Since the board is 2.5-3 mm thick, you can immediately measure according to the height of the door. After removing the formwork, you will have a gap equal to the thickness of the timber used. Next, mark the level of the opposite side from the foundation base or from the first mark using a hydraulic level. After the marks are made, we nail pieces of boards in the shape of the letter - T, the upper edge of which passes under the mark. For this I used 100mm long nails.
Next you need to prepare 3 shields, for this I have 3 boards. Along the edges I have half a stone that will cover the ends of the formwork, the first board is 800 mm long and 2 more 1200 mm each, since the support depth is 200 mm and we must have a reserve. To extend the durability of the wood for further use, I wrapped the formwork boards with cling film, which costs $1 per roll. We lay the bottom board, 800 mm long, on already nailed T-shaped supports; there is no need to nail it to the supports. Next we install the side shields. First, we nail them along the edges to the wall, and then we knock the corners together diagonally from top to bottom. To facilitate the dismantling of the structure, 70 mm nails were driven along the top, on which a binding wire was attached to tighten the top of the lintel formwork. You can use pre-prepared timber, I used this method to save used wood, which can still be useful during the construction process.
How to make a lintel over a door?
To continue laying over windows and doors, you can use several options.
1. Reinforced concrete lintels.
This is the most common option. The jumpers themselves are manufactured at the factory and installed with mortar or glue. The option is proven and reliable, but I didn’t like that concrete has high thermal conductivity, so in this case these jumpers will be the same cold bridges. Another disadvantage is their weight; lifting a one and a half meter jumper to a height with your hands is a real problem.
As a variation in private construction, concrete is sometimes used to pour such lintels directly onto the wall, but in this case the process is more labor-intensive.
2. Gas silicate jumpers.
The same as reinforced concrete lintels are made from cellular concrete. They contain metal fittings inside. Alas, I saw such products on sale already when I finished building the walls of the tower, otherwise I would have used this particular option
.
For a wall made of gas silicate, the ideal option: the thermal insulation is quite consistent with the rest of the wall and, in addition, such a lintel is lightweight, unlike a reinforced concrete one. The photo on the right just illustrates the light weight of such a jumper.
3. Metal corners.
In this case, two metal corners are placed on the last row of the window opening longitudinally to the wall, and the next row of blocks is laid on them. The good thing about this option is that the thermal insulation of the wall remains uniform. The downside is that metal is somewhat more difficult to cover with plaster, and if there is insufficient insulation from iron, rust will appear over time.
4. Wooden beam.
This option is also used quite often, at least my neighbors recommended it to me first. A wooden lintel is laid in the same way as a reinforced concrete one, and naturally, the beam must be well impregnated with an antiseptic. A slight drawback in the heterogeneity of materials can manifest itself in the shedding of plaster on wood joints with cement compositions.
How to perform a load calculation
Unfortunately, despite its importance, lintels in construction are an element that does not receive the attention it deserves because in many cases it is done on the fly without any specifications or requirements. However, it is necessary to follow the technology and correctly calculate the loads. Otherwise, cracks may form in the immediate vicinity of the holes. But these unpleasant consequences can be easily avoided. This will be helped by choosing the correct type of jumper to use and meeting the minimum requirements.
The jumper is calculated based on the applied load, which includes:
- Jumper weight;
- Wall weight taking into account self-supporting capacity;
- Wall weight distribution;
- The load caused by the support of beams or floor slabs on a certain section of the wall;
- Linear dimensions of the jumper.
How to choose a jumper? In many cases, you can rely on the dimensions of tables with standard prefabricated concrete products (series 1.038 for regular and 1.225 for extended openings).
Lintels for window and door openings: types, sizes, installation features
It is difficult to imagine a house in which there are no windows or doors.
In order to make them, structures are needed to cover the openings. Reinforced concrete lintels are used for this purpose. Their main function is to transfer the load from the ceiling and brickwork to the side sections of the walls (piers).
The main materials for making jumpers are:
- Reinforced concrete - due to its affordable price and high manufacturability, is widely used in capital construction;
- Steel (I-beam or channel) is used to a limited extent to cover wide openings where windows and doors are subject to heavy loads.
The markings and overall dimensions of reinforced concrete structures are specified by GOST 948-84 . This building standard divides all industrially produced lintels for window and door openings into several basic types:
- PP - slab (width more than 25 cm).
- PB - block (width less than 25 cm).
- PG - L-shaped beams are equipped with a protrusion designed to support floor slabs.
- PF - façade (used for openings in which the masonry protrudes more than 25 cm from the wall surface).
Depending on the size of the working load, all prefabricated lintels are divided into load-bearing and non-load-bearing. The former perceive and transmit to the walls the weight of the ceiling and the upper part of the wall. The latter can only withstand the load from the wall and their own weight.
The load-bearing capacity of reinforced concrete lintels ranges from 100 to 3,700 kg/m. Concrete provides these structures with the necessary compressive strength, and steel reinforcement absorbs tensile forces.
What is needed to fill jumpers?
I used:
- fittings diameter Ø 12 mm;
- wire rod diameter Ø 6 mm;
- knitting wire diameter Ø 1.4-2 mm;
- edged board 25×200 mm;
- nails 70 and 100 mm;
- cement grade 400;
- river sand;
- crushed diorite stone fraction 20 mm.
I used reinforcement with a diameter of Ø 12 mm, since I plan to build a second floor or attic with a concrete floor and I was on the safe side so as not to calculate the load-bearing capacity of the structure; there will also be a seismic belt under the ceiling; I will describe how to make a seismic belt in the next article.
Standard size range, weight and marking
The GOST dimensions of reinforced concrete lintels are as follows:
- length from 103 to 596 cm;
- height from 12 to 44 cm;
- width from 14 to 38 cm.
The weight of these structures directly depends on the dimensions and can range from 20 kilograms to 2 tons.
Reinforced concrete lintels are mounted on cement mortar. Cutting of these structures for the purpose of adjustment is not permitted. If the wall thickness is large, the opening is covered with several timber lintels, laying them parallel to one another.
Special markings help you understand the wide range of these products. It consists of three groups of alphanumeric symbols separated by a dash.
The first digit indicates the GOST number of the section. It is followed by two letters indicating the type of jumper and two numbers of its length (in decimeters). The second group of numbers contains information about the design load in kN/m. The third group of marking symbols is service and contains data on the degree of concrete density, the presence of mounting loops, the degree of seismic resistance or the class of reinforcement.
For example, let’s decipher the standard designation of a reinforced concrete jumper: 2PB22-3-p:
- 2 — section number (indicated in the GOST table);
- PB – bar lintel;
- 22 – length in decimeters (220 cm);
- 3 – bearing capacity (design load, 3 kN/m);
- p – the product has mounting loops.
To increase the load-bearing capacity of lintels, prestressed reinforcement is used. Such structures can be distinguished by the type of reinforcement indicated at the end of the marking. For example, 5PB21-27-AtV. In this case, AtV is a type of prestressed reinforcement.
Conclusion
Bar lintels - according to GOST they must be made of high-strength reinforced concrete - are a mandatory structural element of virtually any window opening.
It goes without saying, as we already noted in the article, it is possible to make such a part yourself, but if finances allow it, then it is better to use a factory product. At least you will be confident in its mechanical properties, and therefore in the reliability of your windows and doors. The video in this article, in addition to the above, will demonstrate some nuances on this issue, watch it!
Approximate prices and selection features
The most popular length of lintels used in residential construction is from 1.2 to 2.2 meters. The estimated cost of slab-type structures (width 38 cm) ranges from 600 to 4000 rubles. Bar lintels of similar length can be purchased at prices ranging from 250 to 1,700 rubles per piece, depending on the selected width and height.
When choosing the type of lintel above the windows, do not forget that slab lintels can only be installed in a non-load-bearing wall (on which the floor slabs do not rest). Bars can be installed in any type of enclosing structures (non-load-bearing and non-load-bearing).
The width of all manufactured reinforced concrete lintels is a multiple of the width of the masonry. Thanks to this, they are easy to choose for any object. For example, for partitions with a thickness of half a brick (12 cm) and one brick (25 cm), there are more than three dozen standard sizes of products ranging from 1 to 6 meters in length on the market. For thicker walls (1.5 bricks or more), the industry produces slab lintels.
For installation in non-load-bearing walls, it is more profitable to use slab lintels, because their width is equal to the width of the wall. In this case, you will have to use several pieces of timber beams.
When purchasing, you must take into account the support of the lintels on the wall - the main criterion for the reliability of the ceiling. If the area of the supporting part turns out to be less than the standard, then destruction of the material on which this structure rests may occur. To restore the load-bearing capacity of the pier, you will have to do the labor-intensive dismantling of the lintel, dismantling and re-laying the destroyed area.
In general, for a load-bearing brick or aerated concrete wall, the depth of embedding (support) of the lintel should be at least 25 cm. For a self-supporting wall, the size of its supporting part can be reduced to 12 cm. The lintel above the doorway should extend its ends onto the wall no less than 20 cm.
The height of the lintel is selected based on the calculated load on the opening. The developer does not need to perform complex strength calculations, since the full specification of these structures, indicating the dimensions, is contained in the design documentation. During independent construction, you should not engage in amateur activities with the selection of jumpers. It is better to contact the designers for advice.
The technology for installing lintels over openings is determined by the type of wall (load-bearing or non-load-bearing). In the first case, a powerful reinforced concrete beam is placed under the slab. Two other smaller sections are placed in the middle of the wall. The outer one goes down one row of bricks, forming a quarter.
In a non-load-bearing wall, the lintels are the same size. The outer one is lowered by a quarter, and the rest are placed at the same level.
Window opening design
Pouring into formwork
If you are building a house with your own hands, then sooner or later you will have to face the task of covering window openings. There are several ways to solve this problem, and below we will try to give a brief description of them.
The first method involves constructing a lintel made of reinforced concrete using poured technology.
The instructions in this case are as follows:
- At the first stage, we install the formwork in the window opening. For formwork we use boards, the thickness of which should be at least 25-30 mm.
- We support the formwork on vertical wooden beams, which we place inside the opening itself.
Photo of formwork during installation
- Inside the formwork we place a reinforcing mesh made of steel rods with a diameter of about 6-8 mm.
Advice! The reinforcement should be laid on small supports, which will provide a gap between the metal and the lower plane of the poured concrete beam.
- Having additionally strengthened the formwork with transverse bars, we begin pouring the concrete mixture. It is best to use crushed stone as a filler (the ratio of cement, sand and crushed stone in the solution is approximately 1: 2: 4.5).
- We carefully compact the concrete to get rid of air bubbles.
The formwork can be removed pretty soon
As practice shows, it is possible to remove the formwork and begin laying bricks on such a lintel within 48 hours.
Laying the finished part
Using ready-made concrete lintels can significantly save time and simplify work. However, it is worth noting that the price of the product in this case will be slightly higher, and to lift parts to a height it is advisable to have a crane at your disposal.
Installation in the opening: if you have a strong assistant, then you can do it without a tap!
If this does not scare you, then the work is carried out according to the following algorithm:
- First, based on the dimensions of the opening, we select the dimensions of the timber lintels so that the edges of the beam extend into the wall at least 250 mm (this parameter is called the embedment depth).
- Then we erect the masonry in such a way that support platforms are formed for laying the horizontal timber floor.
- We lay a layer of mortar about 20 mm thick under the lintel.
- We lower the concrete part to the selected location and settle it to the required level. Remove excess solution with a trowel.
- If necessary, we form a ceiling over the opening from several such parts.
Further laying of bricks or building blocks can be carried out immediately after the settling and leveling of the lintel is completed.
Designed openings
How to select reinforced concrete lintels.
Calculation of reinforced concrete lintels. So let's first enter some initial data. Let's say we need to calculate which lintel should be used to cover a span of 1350 mm wide in a self-supporting wall 240 mm thick with a wall height above the opening of 800 mm. Construction is being carried out in winter conditions.
A wall thickness of 240 mm means that we will need two lintels 12 mm wide. In winter, a load from the height of the wall equal to the design span is taken on the self-supporting lintel. The design span is calculated as follows:
1350 + 2*100/3 = 1420 mm
100 mm in this case is the minimum depth of support for the lintel. Since the height of the masonry turned out to be less than the design span, in future calculations we will use exactly this height - 800 mm.
Next, we determine the load per 1 linear meter of the product:
0.24*0.8*1.8*1.1/2 = 0.19 t/m = 190 kg/m
In these calculations, 1.8 t/m3 is the weight of the brick, 1.1 is the safety factor, 2 is the number of lintels. So, we need to choose a jumper from those whose load index is at least 2.
As we said above, the minimum support depth for these jumpers is 10 cm, which means the smallest possible length of the jumper in our case is:
1350 + 100*2 = 1550 mm
From the list of standard sizes, a 2PB 16-2 jumper with a length of just 1550 mm and a design load of up to 200 kg/m could suit us. However, we still need to take into account the load from the beam’s own weight, which is 70/1.55 = 45 kg/m. That is, the total load will be 190 + 45 = 235 kg/m, which exceeds the maximum permissible for this jumper.
In our case, a 2PB 19-3 jumper is suitable. Its own load is 80/1.94 = 41 kg/m. Then the total will be equal to 190 + 41 = 231 kg/m, which does not exceed the permissible 300 kg/m for this beam. The length of the lintel is 1940 mm, and this is also suitable for our conditions.
How to avoid installation defects
Summarizing some results, we can give a number of recommendations.
Experienced builders recommend observing the following:
- with an opening width of 1.5 m, the support depth is assumed to be 125 mm or more;
- from 1.5 to 1.8 m – from 200 mm;
- from 1.8 m – from 250 mm;
- windows should be sealed with a quarter;
- if the installation of an armored belt is intended, its filling is carried out several days after the installation of the lintel.
The side edges of the formwork are dismantled after 1-7 days, the bottom - after 28 days
If the installation rules are violated, the lintel may not withstand the load after completion of construction and collapse, which will require urgent reconstruction of the structural element, since the house becomes dangerous. On the other hand, under the load of an improperly constructed lintel, the outer cladding may collapse, which will require dismantling the masonry, dismantling and replacing the element.
How to make beam lintels for aerated block walls yourself is shown in the video:
Types of reinforced concrete lintels.
Before we begin the calculations, let's take a little look at the types of jumpers themselves. To understand what options are available to you, you should open the website of any reinforced concrete manufacturer and see what types of reinforced concrete lintels are present in their product range. By clicking on the link, you will see a long list of standard sizes with their characteristics. To learn how to quickly navigate it, you should learn to decipher the markings. Let's do this using the example of a 2PB 16-2 jumper:
- 2PB - this part of the marking means that the product belongs to a certain type and type of section. In this case, a timber lintel of the second type of section . Bar lintels (PB) can have a width of 120 or 250 mm, which makes it necessary to use several products at once in cases where the thickness of the partition exceeds 120 mm. They also produce slab lintels (PP), the width of which is 380 and 510 mm.
- The second type of section (2PB) has dimensions of 120x140 mm. Other types have the following dimensions: 1PB - 120x65 mm, 3PB - 120x220 mm, 4PB - 120x290 mm, 5PB - 50x220 mm.
Now, knowing the variety of reinforced concrete lintels, you can proceed directly to the calculation.
A little history
For the most part, the lintels above the openings were arched, since the upper semicircular contour of the window somewhat weakened the load. They were made from large-sized stones. These stones were carefully hewn and adjusted to each other; such work required a significant investment of time and effort.
The construction of the buildings took a long time; the slightest inaccuracy in the installation of lintel stones, especially the central ones, could lead to distortion and destruction of the structure. But when the magnificent building was built, its life spanned centuries.
With the advent of brick as a building material, lintels were initially still arched. But it was already easier to work, since the bricks were the same size, and when constructing the lintel, it was possible to make seams of different thicknesses, due to which the required opening radius was achieved
How to choose lintels for brick walls?
Purpose of the lesson: to consolidate theoretical material, learn how to select lintels over window and door openings to brickwork.
Contents of the lesson: on A4 graph paper at a scale of 1:100, draw up a plan diagram for the list of lintels according to the given options, fill out the list of lintels in Form 1 and the specification of precast reinforced concrete elements (Appendix A).
Initial data: diagrams of floor plans (based on materials from practical work No. 1). Jumper types are given in Appendix B.
Procedure for conducting the lesson:
1) Before proceeding with the selection of lintels, it is necessary to complete the floor plan diagrams for the list of lintels. An example plan is shown in Figure 6.1.
To do this, we schematically draw the floor plan of the house with the designation of openings, observing the scale. An example of the circuit is given in Figure 6.2.
2) Assign each opening a position (mark), which is assigned in accordance with the width of the opening and the static function of the wall - load-bearing, self-supporting or non-load-bearing. An example is given in Figure 6.3.
3) Determine the size of the opening: (width and thickness).
4) Select cross-sections of lintels, combining them from several bars or a combination of bars and beams. In load-bearing walls, place “load-bearing” lintels in places where the slab (beam) is supported, and fill the remaining width of the walls with “non-load-bearing” lintels. An example is given in Figure 6.4.
Section diagrams are drawn in table form 2.1 GOST 21.501-93.
Figure 6.1 1st floor plan
Figure 6.2 Layout of the 1st floor
Figure 6.3. Marking of openings
Figure 6.4 Diagram for installing lintels over openings in external load-bearing brick walls
For ease of work, keep a count of the required length of jumpers next to the sheet. To do this, we add to the width of the opening the value of the minimum support of the lintels on the wall: “non-load-bearing” lintel + 240 mm (120 mm on each side), “load-bearing” lintel + 500 mm (250 mm on each side). The brands of jumpers are indicated by positions on the section diagram. The “non-load-bearing” lintel takes only the weight of the masonry, and the “load-bearing” lintel takes the weight of the masonry and the floor resting on it.
5) Select “load-bearing” and “non-load-bearing” jumpers according to Appendix B.
6) In load-bearing, self-supporting walls and partitions, use only “non-load-bearing” lintels.
7) If a quarter is required, lower the external reinforced concrete lintel by a quarter amount equal to 65 mm.
The selected brands of lintels are indicated in the specification of prefabricated lintel elements (Appendix A)
An example of selecting lintels in a building with brick walls
Guidelines: An example of selecting lintels in a building with brick walls. The thickness of the external walls is 510 mm, the internal walls are 380 mm.
Stage I. According to the plan, Figure 6.5, determine load-bearing and non-load-bearing walls
Along the axis, 1-window opening is 910 mm (load-bearing wall 510 mm thick).
Along axis 2 - doorway - 910 mm (load-bearing wall 380 mm thick).
Along axis A - doorway - 1010 mm (curtain wall 510 mm thick).
Along axis B there are 2 window openings – 1510 mm (curtain wall 510 mm thick).
There are two window openings of the same size on the building plan, so they will have the same lintel markings.
All openings have different widths, which means that the marking diagram should have four types of lintels: PR-1; PR-2; PR-3 and PR-4.
Figure 6.5 1st floor plan
Stage II . Draw a diagram of the 1st floor plan (Figure 6.6), indicating the positions of the openings. In the task it will look like this:
Figure 6.6 Scheme of the 1st floor plan with markings of openings
Stage III. Select “load-bearing” and “non-load-bearing” jumpers and sketch their diagrams:
1) To block an opening in a wall 510 mm thick, you will need four 120 mm wide timber lintels: 120 mm x 4 = 480 mm,
plus three 10 mm seams (10 mm x 3 = 30 mm). Thus, we get: 480 mm + 30 mm = 510 mm - a size equal to the thickness of the wall.
We have determined that the wall is load-bearing, so the outermost lintel on which the wall rests must be “load-bearing”.
We get: three jumpers – “non-load-bearing” and one – “load-bearing” (Figure 6.7)
Figure 6.7 Diagram of jumpers in a load-bearing wall 510 mm thick
2) To determine the length of the lintel to the width of the opening, add the value of the minimum support of the lintel on the wall (Figure 6.8 and Figure 6.9)
“non-load-bearing” lintels: 910 mm + 240 mm (120 mm on each side) = 1150 mm.
Figure 6.8 Scheme of supporting a non-load-bearing lintel over the opening
Using the table in Appendix B, we select the required size of the jumper, the size of which will correspond to the calculated length (in our example, 1150 mm). This turned out to be a jumper with the name 2PB13-1, the length of which is 1290 mm, height – 140 mm;
“load-bearing” lintel: 910 mm + 500 mm (250 mm on each side) = 1460 Figure 6.9 Scheme of supporting the load-bearing lintel over the opening
We find the required lintel in the table and do not forget about the design load (Appendix B), since the floor slab rests on the “load-bearing” lintel. We get a 3PB16-37 jumper, the length of which is 1550 mm, the height is 220 mm;
Jumpers PR-2, PR-3, PR-4 are selected using the above method.
When selecting a PR-4 lintel, it is necessary to take into account the wall thickness - 380mm.
In this case, 3 lintels with a width of 120 mm are laid above the opening:
120x3 = 360 mm; 360 mm + 20 mm (two seams of 10 mm each) = 380 mm.
3)We fill out the list of lintels according to form 6.1 - Figure 6.10, putting down positions in the section diagram, then fill out the table of specifications for prefabricated lintel elements (Appendix A). Examples of filling are given in tables 6.1 and 6.2.
Form 6.1 GOST 21.501-93
Figure 6.10 Jumper List
Table 6.1 Example of filling out the list of jumpers
Table 6.2 Example of filling out the specification of jumper elements
Calculation of reinforced concrete lintels.
When erecting brick walls, it inevitably becomes necessary to install a reinforced concrete lintel over the window opening. They are reinforced concrete beams with different sections and lengths, manufactured at the factory. To select the required standard size of the product, it is necessary to make preliminary calculations that will take into account such data as the load on the lintel and the width of the opening. Calculation of reinforced concrete lintels.
At the same time, when talking about the load, they mean the dead weight of the lintel combined with the weight of the wall and ceiling. In the case of residential buildings, where the loads are not so high, all cases are usually divided into three groups:
- The ceiling rests on the wall.
- The ceiling does not rest on the wall, and the wall itself is self-supporting.
- The lintel is laid in a brick partition 12 cm thick.
