How can I strengthen the sexual lags: methods and technology for performing work. How to strengthen a wooden floor so that it does not creak: causes of creaking and ways to strengthen the floor with your own hands Strengthening the floor lag in a wooden

The main element of attic and interfloor ceilings in many private houses is a wooden beam. The service life of wooden floors is limited due to the properties of wood, especially if it has been poorly processed or subjected to stress and moisture.

As a result of such factors, the beam ceases to cope with the function assigned to it (sagging, deflection, curvature is possible) and reinforcement of the wooden floor beams will be required.

In addition to damage and loss of the bearing capacity of the floor and ceiling beams (lag, girders), strengthening may be dictated by an increase in the load on the ceiling.

When to reinforce wooden floor beams

poor condition of the beam structure. The result is damage to the wood. High humidity, temperature changes, the activity of various pests (bark beetles), cracking - all this leads to deformation of the floor beam;

bearing capacity reduction. Under its own weight, constant and variable load, floor beams can bend. According to the regulations, if the deflection is within 1:300, then there is nothing to worry about. For example, if the beam is 2500 mm long. bent 10 mm. this corresponds to the normal deflection value. If the deflection index is greater, it should be strengthened;

the need to increase the bearing capacity of the beam. Associated, for example, with the restructuring of the attic into an attic or living space. Such a restructuring will lead to an increase in constant and variable loads on the floors of the second floor, which automatically requires a change in the cross section of the installed wooden beams.

Within the article, several common ways to strengthen the overlap (, reconstruction) will be given. But, only a professional can accurately answer the question of how to strengthen wooden floor beams and only after analyzing the state of the structure. After all, in each case the decision will be individual.

Using the table, you can get an idea of what section the beam should have under a certain load.

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Ways to reinforce wooden floor beams

The main types and methods of strengthening wooden floors are given in order of increasing labor costs and duration of work.

Amplification type without changing working conditions

Reinforcement with wood trim

The method is used when the tree is damaged. The linings are installed on both sides of the beam from the beam (on the sides or top and bottom), as tightly as possible to it and are fastened (tightened) through with a bolt. In this case, it is important to treat the damaged area and lining with an antifungal solution. In a critical case, if the area is badly damaged, it is better to remove it. To strengthen the beam, you need to fasten the overlay along its entire length.

Reinforcement of spans with metal overlays (plates) or bar prostheses

Steel plates are used instead of the wooden ones described above. The metal also needs to be treated with an anti-corrosion solution. The diagram of the device is shown in the figure.

Strengthening the overlap with carbon fiber (CFRP)

Modern reinforcement technology (carbon fiber reinforcement). Carbon fiber (tapes, sheets, plates, threads, fabric) is glued in several layers until the required beam stiffness indicators are reached. The ease of use and lightness of the material lead to the fact that carbon fiber is gaining popularity as an effective tool for the restoration of beams and building structures.

Below is a diagram of reinforcement (strengthening) of floor beams with carbon fiber.

Reinforcement at the ends with wooden or metal prostheses

The technology allows to strengthen the beam at the junction with the bearing wall. This is exactly the place where, due to temperature changes, wood damage occurs faster.

The diagram below shows the technology of reinforcement with prostheses from a channel, a rolled profile

Installation of a bar prosthesis

The bar prosthesis of the Daidbekov system is made from two paired trusses, which are made from scraps of reinforcing steel with a cross section (diameter) of 10-25 mm. The length of the prosthesis should be 10% more than twice the length of the decayed end of the beam, but not more than 1.2 m.

Install temporary supports under the ceiling at a distance of 1-1.5 m from the bearing wall, consisting of racks and a run.
Disassemble the ceiling from below to a width of 75 cm and from above - 1.5 m from the wall.
Cut off the damaged section of the beam (0.5m)
Bring the prosthesis blank vertically into the interfloor overlap and turn it to a horizontal position, first pushing it onto the beam, then pushing it into the wall niche in the opposite direction.
Move and nail the sliding bar.

Amplification type with changing working conditions

Strengthening wooden floors in such ways provides for a significant restructuring of the supporting structure of beam spans.

Non-standard solutions

If it is not possible to strengthen the wooden floor beams, you can try to unload them, i.e., distribute the load from the existing beams to additionally installed elements.

Reinforcement of floors by installing supports under load-bearing beams

Supports supporting beams from below are a good way to redistribute the load from the beam to the support.

Strengthening floors by installing additional beams

If the existing logs are safe and sound, it is possible to increase their bearing capacity by increasing their number. Installing additional wooden beams will increase the load on the structure. When installing new logs, it is imperative to protect their ends with roofing material to avoid damage.

We hope that from the above methods of reinforcing wooden floor beams you will choose the one that will solve your problem in the best possible way and at minimal cost.

One of the main structural elements used for the construction of floors of attics or rooms on the second floor, mainly in low-rise individual construction, is a wooden or metal beam, which simultaneously performs the functions of a floor log and a basis for fixing ceiling coverings. The low cost of initial building materials and the possibility of constructing ceilings without the use of lifting mechanisms contributed to the wide distribution of beam ceilings.

Deflection lag

Entering some, especially old, houses, even with the naked eye, you can notice the deflection of the ceilings of the second, or, less often, the floor of the first floor, which is the result of an incorrect calculation of the bearing capacity of the lag or exceeding the permissible load on the floors. As the practice of operating multi-storey buildings built in the first half of the 50s of the twentieth century, where wooden interfloor floors were used, calls for, by 2000, the deflection of the ceilings was from 70 to 100 mm, which led to the need for major repairs of the building with the strengthening of the load-bearing elements of the floors . And this is provided that an accurate engineering calculation of loads and lag sections is carried out at the design stage. And what can we say about individual buildings, when the calculation of the bearing capacity of the lag was carried out "by eye" on the advice of "competent" specialists.

Very often, the quality of the material used, the excessive moisture content of the wood, the insufficient thickness of the rolled metal from which the beam is made, and many other reasons leading to sagging, for example, the overlap of the second floor under load, also affect the amount of lag deflection. Incorrect calculation of the bearing capacity can lead not only to the occurrence of deflection of the log, but also to the complete destruction of the structure and the collapse of the floor down, and when no one expects it.

When is it necessary to strengthen the lags?

If the owner of the house noticed the sagging of the upper floor, then the first thing to do is to take simple measurements and assess the condition of the structures, the amount of static load in order to determine the amount of sagging of the ceiling or changes in the curvature of the floor in order to decide on the need to strengthen the log.

Any floors under the influence of their own weight, static load of the structures and objects installed on them sag over time. The allowable sagging value is taken as 1:300, that is, if a three-meter beam is bent by 10 mm, there is no reason for concern, but if this value is greater, then measures must be taken to eliminate deformation and strengthen the structure.

Strengthening of metal structures

Metal structures used as floor beams can be reinforced with additional rolled metal products by welding or bolting. To do this, the surface of the floor or ceiling is disassembled, if necessary, adjustable supports are placed under the floor beams to eliminate deformation, and the structure is reinforced with standard rolled metal products of the required section, the calculation of which is performed using special tables and methods.

Reinforcement of wooden elements

Existing structural elements of a wooden floor, depending on their condition, can be strengthened in several ways:

With the help of overlays from a bar, by performing a simple mathematical calculation, when the width of the existing bar is subtracted from the tabular value of the section of the required floor beam. The beam and beam are fastened with bolts with metal plates that prevent the destruction of wood at the point of attachment and the weakening of the structure. The existing beam is lifted with jacks until a flat floor surface is obtained, after which the overlay and the beam are fastened together;
Using metal strips 10 mm thick and 10-20% less than the height of the beam as overlays. To prevent deformation of the strip and reduce strength, the number of fastening bolts should be increased by 25% compared to wooden elements. Linings are installed on one or both sides of the beam, depending on the load on the load-bearing elements of the floor of the upper floor;
Wooden floor beams damaged by insects or putrefactive bacteria can be reinforced with prostheses welded from a bar in the form of a spatial truss, or with the help of a channel of the required size. The channel, installed as a prosthesis, is selected from a standard range of rolled metal, and for the manufacture of a spatial bar truss, it is required to perform a rather complex strength calculation, which only a qualified specialist can do.
Strengthening the bearing capacity of interfloor structures can be done by installing an additional number of beams, but these works require making holes in the load-bearing walls, which in some cases is difficult to perform.

When using metal elements to reinforce the load-bearing interfloor structures, especially for the destroyed parts to be removed, it is necessary to provide for the installation of elements on which the floorboards of the upper floor will be fixed. The fastening must be reliable and durable, excluding the possibility of loosening and the appearance of squeaks.

Logs reinforced in various ways make it possible to increase the carrying capacity of load-bearing interfloor structures and the overall safety of the operation of existing buildings without significant capital investments and a large amount of construction work.

A board of suitable size is adjusted to the place intended for it, for which:

If the board is too thick, mark the positions of the log on it and choose grooves for them with a chisel;

If the board is very wide, cut the edges, beveling them a little down;

If the board is thin, thick cardboard or plywood is placed on the logs before it is fastened.

If the old board is sawn off next to the log, a support bar for the new board is attached to the latter with screws. (In the future, when replacing the board, the screws will be easier to remove.)

SOLVING LAGS PROBLEMS

A lot of warped places, sagging floors, cracked or damaged boards are signs of a bad state of the lag. Problems with lags most often occur on the first floors, where there is a high probability of moisture. But in any case, if you have to lift more than two boards, you need to check the state of the lag.

Rot and woodworms are immediately visible, and the logs affected by them must be repaired immediately. Darkening or the presence of areas with soft wood on the logs indicate the beginning of decay due to increased dampness. Lags can be saved if you take action in time.

The reasons for the sagging of the floor with serviceable lags can be:

Weakening of the lag due to selections for pipes and cables;

Insufficient initial strength of the lag or the material from which they are made.

These defects can be eliminated by reinforcing the joists with overlays or increasing their rigidity by inserting spacers between the joists. But for such repairs, a significant part of the floorboards will have to be removed.

If the board is sawn off near the log, a bar is fastened to the side of the latter with screws to support the new board.

On the floor of the first floor, you can reinforce the sagging log with an overlay resting on the nearest floor beams.

In a too thick floorboard, grooves are selected above the lags. Under a thin board, thick cardboard or plywood is placed on the logs.

criss-cross struts made of 50x50 mm bars. They are fixed in increments of 600 mm between the defective log and adjacent logs.

not less than 900 mm. Bolts are installed in increments of 300 mm. Between the lining and the lag, star washers are laid.

52 Professional Tips #3" 11

Wooden floors on logs are one of the oldest methods of arranging floors and the only one used in the northern regions of our country. Modern materials have only improved the old technologies, due to which the scope of application has significantly expanded and performance has improved. Before proceeding directly to the consideration of various options, you should familiarize yourself a little with the engineering requirements for calculations.

Logs are distinguished from beams by their smaller size and mobility. If the beams after installation cannot be moved, the repair is very long and labor-intensive, then the logs are a mobile architectural element. They are much easier to mount, if necessary, repairs are made faster.

Before proceeding with the construction of the floor, you need to study the requirements of regulatory documents for the dimensions of the log and the distance between them, taking into account the thickness of the floorboards.

Log section table with a step of 70 cm

Table of the distance between the lags depending on the thickness of the board

In order to learn how to independently make calculations based on tables, it will be useful to consider the simplest example. Initial data: the length of the room is 10 m, let's take a floorboard 30 mm thick.

Method of calculation

According to the table, with such a board thickness, the distance between the lags is 50 cm, with a room length of 10 m, 20 lags will be needed. The removal of the lag from the walls cannot exceed 30 cm. This means that we will have to increase their number by one piece, the distance between the rest will decrease to 45 centimeters.

Important note. During calculations, all rounding must be done only downwards, thus creating an additional margin of safety.

There is no need to calculate dimensions and distances to the nearest millimeter, no one is engaged in such measurements. By the way, during construction, the vast majority of architectural elements and structures are measured in centimeters, the highest accuracy is half a centimeter. Millimeters are almost never used during measurements.

Floor base options

These types of floors can be placed on a wooden and concrete base or on the ground. Each option has its own technological features, which must be kept in mind during the production of work. As for the specific purpose of the premises, taking into account this parameter, the floor base and its performance characteristics are selected. The device technology itself remains almost unchanged. There are, of course, options for warm and cold floors, but these features also have a common construction algorithm.

The device of a wooden floor on logs on wooden bases

Such floors can be made both in wooden and brick buildings, they can have several varieties. It is necessary to think over the features of floor coverings at the design stage of the building. Not only the purpose of each room and its dimensions are taken into account, but also the climatic zone of residence, microclimate requirements and the financial capabilities of the developer. Below are step-by-step recommendations for the construction of this type of floor.

Depending on the specific conditions, the algorithm can be changed somewhat, but all the main construction operations are mandatory. Moisture-resistant OSB boards or plywood sheets can serve as the base. The design of floor coverings provides for the possibility of laying heaters; it is allowed to use rolled and pressed glass wool or polystyrene. If there are heaters, then be sure to put hydro and vapor barrier.

Step 1. Take the dimensions of the room and calculate the number of lags, taking into account the above recommendations. Prepare materials and tools, markup. Do the work slowly, the mistakes made at this stage have extremely negative consequences. Removing them will take a long time.

Step 2. Start installing logs from the extreme wall. If the room has black floors, then the logs can be fixed directly to them. To facilitate the work, it is better to use perforated metal squares, such elements significantly speed up the work and increase the stability of the lag. According to the mark on the wall, taking into account the thickness of the floorboards, set one end of the log, fix its position.

Practical advice. During the installation of the extreme lags, do not fix them immediately; at first, the screws should only be baited. This will enable final fine adjustments to be made.

Do the same actions at the second end of the log, constantly monitor its position in terms of level. When the log lay down normally, you can firmly fix the ends and proceed with the installation of intermediate fasteners. The distance between them depends on the thickness of the boards that are used for the logs, it is about 70 centimeters.

Step 3 Between the extreme lags you need to pull the ropes, set all the remaining lags along this line. Constantly check the level, the installation accuracy should be ± 1–2 mm. There is no point anymore, it takes a lot of extra time. A small difference in height will be removed during the finishing of the front surface of the floorboards.

Step 4 If the floors are warm, then it is necessary to lay thermal insulation between the lags; waterproofing and vapor barrier are used to prevent moisture from entering. The distances between the lags must be adjusted taking into account the length and width of the heaters. It can be either mineral wool or polystyrene, or bulk types of insulation. If all the preparatory work is completed, then you can start laying the floorboards.

There are options for mounting the log on the floor beams. These are the so-called ventilated floors, most often used for non-residential premises. It is not necessary to observe special accuracy, the alignment of dimensions is done by lags. Logs to the beams are attached with nails or self-tapping screws on the side. The work algorithm is the same. First, the extreme ones are placed, a rope is pulled between them and all the rest are fixed along it.

Ventilation is carried out through special vents in the foundations, the distance between the ground and the floor must be at least fifty centimeters. Otherwise, the air exchange rate does not meet the required indicators, and this causes damage to wooden structures.

Floor installation on wooden logs for concrete

Such floors are considered more complex, time-consuming and expensive; all wooden structures must be reliably protected from direct contact with concrete. Otherwise, the structures will quickly become unusable and they will have to be changed prematurely. There is a chemical way to protect the log from decay processes with the help of various impregnations. They are quite effective, they really prevent the process of wood damage. But unfortunately, impregnated wooden structures can no longer be considered environmentally friendly, and it is for the sake of this indicator that most developers install natural wooden floors.

If the logs are placed over the entire area on concrete, then waterproofing is required between them.

But they can also be fixed with the help of metal squares, which allows you to make a gap between the base and the lag. It must be borne in mind that in this case the bearing characteristics of the floor are somewhat reduced.

This method of fixation has its advantages. Firstly, direct contact of wooden structures with concrete structures is completely excluded. Secondly, logs can also be installed on a black screed. With the help of corners, you can eliminate irregularities of several centimeters, there is no need to make a final screed. This saves a lot of time and money.

The second way of laying on a concrete screed - logs are placed directly on it, material based on modified bitumen is used for insulation.

Laying log on the ground

The method is used for outbuildings, bathhouses, gazebos, verandas, etc. Wood must be treated with antiseptics. The foundation is better columnar, if you want to make a more durable tape, then it is necessary to provide ventilation for natural ventilation in advance.

How is this floor made?

Step 1. Remove the fertile layer of soil. It can be sprinkled with beds or level the area in front of the house.

Step 2. Mark up the columns. The distance between them is selected taking into account the load and the dimensions of the lag. Columns can be made concrete, block or prefabricated. The dimensions of the supports are approximately 40 × 40 cm, the depth of burial is within 30 cm. A layer of sand ≈ 10 cm thick should be poured onto the bottom and compacted.

Step 3 Fill the supports with concrete. For the preparation of concrete, two parts of crushed stone and three parts of sand should be taken per part of cement. Water is added as needed. Formwork can be omitted in the ground; formwork from boards or OSB trimmings is installed above the ground level. During the manufacture of formwork, you need to use a level, all edges must be strictly vertical.

Practical advice. It is much easier to make columns from ready-made blocks. Horizontal alignment must be done along the rope. After the extreme ones are set according to the hydraulic level, a rope is pulled between them. Deviations should not exceed ± 1 cm. This variation is eliminated during the installation of the log.

Step 4 Proceed to fixing the lag, you also need to start work from the extreme ones. Spacers can be used for precise horizontal alignment. It is undesirable to take wood wedges, over time they will dry out and wobble will appear: the floor will begin to creak unpleasantly while walking. Between wooden structures and concrete surfaces, it is imperative to put two layers of roofing material for reliable waterproofing.

Step 5 After the extreme logs are laid, a rope is pulled between them and all the rest are laid under it. Logs are fixed with metal squares on dowels and self-tapping screws. To increase stability, it is recommended to install them on both sides. Floor boards can be laid immediately on the logs or pre-laid with a subfloor. The final choice depends on the characteristics of the operation and purpose of the premises.

Always select logs with a margin of safety, especially in cases where the installation method involves bending loads. It must be remembered that correcting mistakes made during the construction of floor coverings is always much more expensive than the production of work with quality materials and in compliance with the recommended technologies.

Choose your boards carefully. They must be absolutely healthy with no signs of rot. The presence of through cracks and rotten knots is completely prohibited. If there are large healthy through knots, then you need to install the logs in such a way that there is an emphasis under them.

During the fastening of the lag, do not allow the possibility of reeling.

Most lag wobbles cause very unpleasant floor squeaks while walking. To eliminate such phenomena, it will be necessary to remove the floor coverings, which is long and expensive, it is not always possible to keep the dismantled materials in a state suitable for reuse.

Video - Installation of a wooden floor along the logs

When organizing wooden floors, transverse beams are often used, especially for rooms located on the 1st floor. They can be made from wood, composite material made of concrete and steel, metal, etc.

What are wood logs

Cross beams are logs that are mounted on bricks or reinforced concrete base. They are made from a single bar made of square or round wood. To save money, some owners perform them from spliced boards installed on the edge.

Floors organized on wooden blocks

Advantages of using flooring on wooden bars

With the same lifting height, floors organized with the help of transverse beams have a much lower weight of the structure, for example, when compared with monolithic concrete.
The floor, organized in a similar way, is perfectly ventilated.
Between the bars of the flooring, you can put communications of a hidden type.
The floor, which has an undivided space under the flooring, can be additionally thermally insulated and soundproofed.
Floors of this type can be leveled even if they have a large difference in height.
The floor, which has a similar design, can be easily dismantled for reconstruction.

In order for the floors to be reliable and serve for a long time, the cross section of the beams must be correctly calculated. To do this, you can use specialized tables.

Beam section calculation table

However, there are similar situations when the floors need to be strengthened. This happens in the following ways:

the load on the floor increases, for example, due to the conversion of the attic floor into an attic;
damage to the load-bearing elements of wood, from which the floor was made, by fungal diseases or due to damage by rodents;
excess of the bearing capacity, for which the floor was originally calculated;
the first erroneous calculation of the section of wood elements, etc.

Attention! The floor is allowed to have a deflection of 1:300. In other words, if the beam is 3 meters long and the deflection is 10 mm, then this is an acceptable value, and no reinforcement is required.

There are several options for reinforcing the cross beams. Let's take a look at some of them.

We strengthen the floor by reinforcing wooden structures with overlays

It is done if cracks are found in wood structures or the floor begins to bend strongly.

Before carrying out work, it is necessary to unload the floors, and it may also be necessary to dismantle the coating. Unloading the structure is done by installing non-permanent racks of logs, timber or jacks. The number of racks and their cross section depend on the length of the span of the structure and the load.

If the cross beams are made of a solid log, it is allowed to install a single post at the deflection point. If the structures are composite, then several racks must be installed. In the place where the floors sag, a jack is installed, and with its help they bring the system to a horizontal position.

If the floor is bent due to the fact that from the very beginning a beam with a smaller diameter than required is used, then, using the table, calculate the required diameter. Further, the diameter of the beam is subtracted from the required value. The resulting value will give us a small lining thickness, which is used to build up the beam.

The overlay is placed on one or both sides and stitched to the outdated system using bolts with iron linings. They are necessary in order to eliminate the destruction of the tree under load at the attachment point.

To improve the floor, replace wood overlays iron can be used. In this variant, strips of metal 10 mm thick and 10–20% less than the width of the transverse beam are used. As in case wood overlays, iron are mounted on one or 2 sides of the structural element, only the number of fasteners is increased by approximately 25%. Metal before installation is finished with anti-corrosion compounds.

If a gain is done when the timber is damaged, then a support should be installed, the damaged area removed, and this place should be treated with antifungal compounds. The pads themselves are also treated with an antifungal compound.

Gain beams using wood overlays

Gain can be done with carbon fiber, which is used, for example, if the beam is not damaged by a fungus, but cracks have formed in it.

In this version, the damaged part is wrapped with carbon fiber, which is attached using a specialized adhesive compound made from epoxy-based resin. Such material makes it possible to improve the design without increasing the thickness of the reinforced element. A layer of carbon fiber 1–5 mm is wound where it is necessary, depending on the planned load and the condition of the beam.

As soon as the repair work is completed, the supports are removed.

Gain wooden beams with prostheses

If the beam is damaged by a fungus or insects, then the floors can be repaired by reinforcing the structure with prostheses. The prosthesis is a specialized small iron farm, which is put in place of the damaged area.

Prostheses are made from a channel or welded with iron rods. For repair work on your own in this option, it is better to use a channel, since it is of standard size, and you only need to choose a suitable prosthesis. Due to its shape, the channel perfectly withstands existing floor loads.

Attention! For the production of a prosthesis from iron rods, it is necessary to make a rather complicated strength calculation, and therefore it is recommended to entrust this matter to a professional.

To improve the floors, use prostheses made from a channel or a metal rod.

Often, damage occurs in that part of the beam that rests on the wall surface, because it is here that the transverse beams are prone to extreme temperature fluctuations and very high humidity. If this part of the structure is damaged, then in order to fix floors, use a system of wood and iron prostheses.

at the beginning of the work to strengthen the structure, the damaged component is supported by supports. The damaged area is cut out. The cut is finished with antibacterial compounds.

Next, wood linings are selected so that the total thickness of the structure is slightly larger than the thickness of the original structure. An insert is placed between the linings. The liner is attached to the lining with nails.

Gain structures with wood prosthesis

Reinforcing floors between floors

To fix floors, which are located between floors, can be from below install auxiliary supports, which will take away part of the load on themselves. In this embodiment, the floors will be able to carry a high load.

install auxiliary intermediate beams. This will also enable fix floors.
If possible, you can install auxiliary intermediate cross beams.

If it is not possible to improve the timber in the ways listed above, then it is possible to unload the structures by redistributing the load on additionally installed parts.