How to strengthen the floor logs from deflection. Strengthening the wooden floor - ways to strengthen the ceiling and beams of the second floor

When organizing wooden floors, logs are often used, especially for rooms located on the 1st floor. They can be made of wood, reinforced concrete, metal, etc.

What are wooden logs

Logs are transverse beams that are installed on bricks or reinforced concrete base. They are made from a solid wooden beam of square or round section. To save money, some owners make them from spliced boards installed on the edge.

Floors organized on logs

Benefits of using flooring on logs

With the same lifting height, the floors organized with the help of a log have a much lower weight of the structure, for example, compared to reinforced concrete.
The floor, organized in this way, is well ventilated.
Hidden communications can be installed between the flooring bars.
The floor, which has free space under the flooring, can be additionally insulated and soundproofed.
Such floors can be leveled even if they have a large difference in height.
A floor that has this design can be easily dismantled for restoration.

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 special tables.

Beam section calculation table

However, there are situations when the floors need to be reinforced. This happens in the following cases:

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

Attention! It is allowed that the floor has a deflection of 1:300. That is, if the beam has a length of 3 meters and the deflection is 10 mm, then this is an acceptable value, and no reinforcement is required.

There are several ways to enhance the lag. Let's consider some of them.

We strengthen the floor by reinforcing wooden structures with overlays

It is performed if cracks are found in wooden structures or the floor begins to sag strongly.

Before performing work, it is necessary to unload the floors, and it may also be necessary to dismantle the coating. The unloading of the structure is carried out by installing temporary 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 logs are made of a single log, it is allowed to install a single rack at the deflection point. If the structures are composite, then you need to install several racks. 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 sagged due to the fact that a beam of a smaller diameter than required was initially used, then using the table, calculate the desired diameter value. Next, subtract the diameter of the beam from the desired value. The resulting value will give us the minimum thickness of the lining, which is used in order to build up the beam.

The overlay is installed on one or both sides and stitched to the old structure using bolts with metal linings. They are needed in order to prevent the destruction of the tree under load at the attachment point.

To reinforce the floor, instead of wooden overlays, you can use metal ones. In this case, strips of metal 10 mm thick and 10–20% less than the width of the log are used. As in the case of wooden overlays, metal overlays are installed on one or both sides of the structural element, only the number of fasteners is increased by about 25%. The metal is treated with anti-corrosion compounds before installation.

If reinforcement is performed when the beam is damaged, then it is necessary to install a support, remove the damaged area, and treat this place with antifungal compounds. The pads themselves are also treated with an antifungal compound.

Strengthening the beam with wooden overlays

Reinforcement can be done with carbon fiber, which is used if the beam is not damaged by fungus, but cracks have appeared in it.

In this case, the damaged part is wrapped with carbon fiber, which is fixed with a special adhesive based on epoxy resin. Such material makes it possible to strengthen the structure without increasing the thickness of the reinforced element. A layer of carbon fiber 1-5 mm is wound on the right place, depending on the expected load and the condition of the beam.

After the repair work is completed, the supports are removed.

Reinforcement of wooden beams using 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 special small metal truss, which is installed instead of the damaged area.

Dentures are made from a channel or welded using metal rods. In this case, it is better to use a channel for repairs on your own, since it is produced in standard sizes, and you only need to choose a suitable prosthesis. Due to its shape, the channel perfectly resists existing floor loads.

Attention! To manufacture a prosthesis from metal bars, it is necessary to perform a rather complicated strength calculation, and therefore it is better to entrust this matter to a specialist.

To strengthen the floors, use prostheses made of a channel or a metal rod.

Often damage occurs in that part of the timber that rests on the wall, since it is in this place that the logs are subject to the influence of sharp fluctuations in temperature and high humidity. If this part of the structure is damaged, then a system of wooden and metal prostheses is used to strengthen the floors.

Before starting work on strengthening the structure, the damaged element is supported by supports. The damaged area is cut out. The cut is treated with antibacterial compounds.

Next, wooden linings are selected so that the total thickness of the structure is slightly greater than the thickness of the original structure. An insert is inserted between the overlays. The liner is fixed to the lining with nails.

Strengthening the structure with a wooden prosthesis

Reinforcing floors between floors

To strengthen the floors that are located between floors, you can install additional supports from below, which will take part of the load on themselves. In this case, the floors will be able to carry a large load.

If possible, additional intermediate beams can be installed. This will also strengthen the floors.
If possible, you can install additional intermediate lags.

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

Thanks to the lags, you can make a perfectly flat floor in any room. Modern technologies in construction are unique opportunities. For many, such words as bridging and polymers, tape floor, GOST, cabinets, column connections, dimensions 100x200, or 150x50 do not say anything. But those who have already encountered the repair know that we are talking, most likely, about the field on the logs. Someone just wants to reinforce the floor, while someone needs to lay a new, durable and beautiful one. And very often the technology of arranging the floor on the logs is used.

Their advantages: what are lags

It’s worth saying right away that laying the floor on logs is in many cases just the perfect solution. Indeed, this method has many advantages. It is very important that the floor is warm.

Among the advantages of the lag, it is worth noting the reliability and low price.

It is also worth making the floors on the logs as:

Noise from neighbors in the apartment below will not penetrate to you;
Installation can be completely done by hand;
The cost of the floor and work is quite acceptable;
Wires and pipes, not very attractive, but necessary, can be hidden under such a floor;
This is an eco-friendly floor.

When you work, the smell in the room will be very pleasant. For many, by the way, the smell of processed wood is a real antidepressant, which by itself cheers up and sets you up for work.

Lags are called bars, which are needed as a support for a hard floor covering. Logs can be made of metal, polymers, reinforced concrete, but usually wooden logs are taken to be laid. Wood is easier to work with and cheaper.

Logs differ from beams in mobility and smaller sizes. Beams after installation, to give a figurative example, cannot be moved, but logs can. Yes, and it is much easier to mount them, and if repairs are needed, it will be simple and quick.

Installation tools: laying floors on logs in the house

To work, you will need a hammer, level, screwdriver or drill, knife. The following materials are taken for the manufacture of such a floor - pieces of chipboard or plywood, any insulation, self-tapping screws, corners or U-shaped fasteners.

All the necessary tools for mounting the log can be purchased at any hardware store at an affordable price.

To prepare the floor for installation, the entire floor area should be freed. Check the old screed, if the concrete floor is already deprived of integrity, it needs to be patched up. Then debris and dust are removed, everything should be clean. Then you need to eliminate the defect of the subfloor. The floor should be primed. No matter how much the pros say about the need for a primer, there is some kind of careless attitude towards this procedure. The primer is right, it must be absorbed and dry, and only then the flaws are filled.

Then, the maximum point of the surface in the room is calculated from the level. You need to set a mark so that this is a guide for subsequent work. And then the work develops according to two possible scenarios: to make a screed, bringing the surface to one level, or to set the logs to the level with small plywood spacers.

Step-by-step instructions: do-it-yourself installation of a floor lag

It all starts with the fact that solid or connected bars are laid out across the width of the room. The first bar and the last will be located 20 cm from the wall. You need to calculate the step between the lags in advance.

It is necessary to bring the level of the floor, the quality of the finish coating will depend on this moment;
All bars must be placed in the same horizontal plane;
For lifting, linings of bars or plywood are used;
It is not enough to install, you need to fix the logs, for this, either self-tapping screws are used, or anchor bolts are installed;
The length of the fastening interval is 70-80 cm, you drill the beam, capturing the concrete foundation, and tighten the self-tapping screw.

To make the floor warm, heat-insulating material should be placed between the lags.

There is an option to install a log and on adjustable fasteners, turning it, you will achieve the desired result. By the way, if the finish is not a wooden floor, but a small ceramic tile, then the distance between the bars will be 30 cm. Only in this situation there are also transverse logs, moreover, at the same distance. They need to be fixed at an equal level with longitudinal bars (a corner is used). Such reinforcement of the structure must be used, because the size of the tile is small.

Modern logs for the floor: the size of the timber

The reliability of the design depends not only on whether you use a board or metal elements, but also on whether the calculation is correct. First, the length and thickness of the beam is determined. Length is the length and width of the house. In this case, it is imperative to leave a gap, and the beam, respectively, is selected 20-30 mm less.

Such a ventilation gap is necessary - it prevents deformation if changes in humidity and temperature occur.

The cross section of the beam, its size is more difficult to calculate. Here, the potential load on the floor is important, as well as the size of the spans between the support points of these lags. There is a table that makes the calculations easier. The larger the span, the thicker the beam will be. For example, the span size is 3m, which means that the lag section is 150 by 80 mm. The sectional shape is usually rectangular. Install the beam on the edge so that the logs can withstand high pressure.

What is the distance between the floor joists

The lag step will depend on the thickness of the flooring. If you use flooring from durable thick boards, logs can be fixed relatively rarely. Well, a thin and not particularly durable coating requires more lag.

The distance between the lags should be chosen depending on the area of \u200b\u200bthe room and its design features

Dependence can be seen in a couple of examples. For example, the thickness of the floor board is 30 mm, which means that the interval between the lags is half a meter. Or a thickness of 40 mm, therefore, a step between lags of 700 mm.

You really don't need an exact calculation. It will be sufficient to take just the distance between our lags of the average value. And if at the end of the installation you saw that the distance was inaccurate, then make the step between these last lags smaller, and the structure will be strong.

Beam size: floor joists

The length of the beam should be approximately 3 cm less than the width and length of the room where the floor is laid. The length of the log must necessarily be less than the length of the room in order to avoid deformation of the structure if temperature changes occur. It is good to make logs from solid materials, but sometimes the bar needs to be lengthened.

Two elements are spliced according to the rules:

There should be supporting elements under the splicing point, for example, poles;
If adjacent logs are spliced, then the splicing points are positioned relative to each other with an offset.

The connection must comply with these conditions, otherwise there may be a threat of low floor stiffness in the very place where the timber is spliced. Neighboring logs are spliced with an offset of a meter. This fact affects the size of the bars taken.

Algorithm: laying the floor on the logs with your own hands

You need to lay a wooden log from the corner of the room. Then, the first row is usually placed with a tongue and groove relative to the wall, and in this case, the gap between the wall and the lag should be 1 cm (to avoid wood deformation). Then a number of logs are laid offset relative to the first log, by about a few bars.

In order for the boards to be firmly attached to the base, you need to knock a little on the wood with a construction hammer. This is necessary for the reliability of fastening. Boards are attached along the wall, fixed with screws. The screws can be on the surface, it doesn't matter, the skirting boards will close them.

Hint: how to increase sexual lags

Everything is individual here, but there are some general rules. For example, if the floor lags and the strapping lower beam are at the same level, then they can be fastened together with forged staples, or perforated corners will help. If the logs are located below the strapping beam, then a metal bracket is used.

Roughly speaking, the main purpose of the reinforcement is to firmly fix the floor lag and the bars of the lower crown. In this case, when strengthening the floor, the floorboards will stop moving apart. Still, as an option, you can rally the floors until the cracks are eliminated, and the gaps are simply covered with skirting boards.

Modern technologies in construction are unique opportunities. For many, such words as bridging and polymers, tape floor, GOST, cabinets, column connections, dimensions 100x200, or 150x50 do not say anything. But those who have already encountered the repair know that we are talking, most likely, about the field on the logs. Someone just wants to reinforce the floor, while someone needs to lay a new, durable and beautiful one. And very often the technology of arranging the floor on the logs is used.

It’s worth saying right away that laying the floor on logs is in many cases just the perfect solution. Indeed, this method has many advantages. It is very important that the floor is warm.

It is also worth making the floors on the logs as:

Noise from neighbors in the apartment below will not penetrate to you;
Installation can be completely done by hand;
The cost of the floor and work is quite acceptable;
Wires and pipes, not very attractive, but necessary, can be hidden under such a floor;
This is an eco-friendly floor.

When you work, the smell in the room will be very pleasant. For many, by the way, the smell of processed wood is a real antidepressant, which by itself cheers up and sets you up for work.

Installation tools: laying floors on logs in the house

Step-by-step instructions: do-it-yourself installation of a floor lag

It is necessary to bring the level of the floor, the quality of the finish coating will depend on this moment;
All bars must be placed in the same horizontal plane;
For lifting, linings of bars or plywood are used;
It is not enough to install, you need to fix the logs, for this, either self-tapping screws are used, or anchor bolts are installed;
The length of the fastening interval is 70-80 cm, you drill the beam, capturing the concrete foundation, and tighten the self-tapping screw.

Modern logs for the floor: the size of the timber

Such a ventilation gap is necessary - it prevents deformation if changes in humidity and temperature occur.

What is the distance between the floor joists

Dependence can be seen in a couple of examples. For example, the thickness of the floor board is 30 mm, which means that the interval between the lags is half a meter. Or a thickness of 40 mm, therefore, a step between lags of 700 mm.

Beam size: floor joists

Two elements are spliced according to the rules:

There should be supporting elements under the splicing point, for example, poles;
If adjacent logs are spliced, then the splicing points are positioned relative to each other with an offset.

Algorithm: laying the floor on the logs with your own hands

Hint: how to increase sexual lags

How to put logs on the floor (video)

Today, when the floor can be laid, poured, polymeric coatings can be made, plastic parts, brick inclusions, etc. can be used, many refuse to use the classic methods of repair. But sometimes, instead of complex and expensive designs, old and proven methods are required. The same floor on the logs, which will "make friends" with both a wooden and a brick house.

Sometimes in houses of individual construction, one can observe the deflection of the ceilings of the second floor or, which can be found less often, the floors on the first floor. This phenomenon occurs due to incorrect calculations or exceeding the permissible load. How to strengthen the wooden floor and return the bearing capacity of the floor beams, that is, the log, can be found in the article.

Logs are beams that are installed across the building on bricks or reinforced concrete base. Most often they are a solid wooden beam of square or round section. There is also an economical option when the logs are built from spliced boards.

Flooring on logs has the following advantages:

Attention! When choosing a wooden floor, it is imperative to correctly calculate the cross section of the beams. Only in this way will they serve reliably and for a long time.

Under certain circumstances, it is required to strengthen the lags. They do this for several reasons:

With a significant increase in the load on the floor. This happens after the conversion of the attic into a residential attic.
Sometimes load-bearing beams made of wood are damaged by fungi, insects or rodents.
Initially, the cross section of wooden elements was incorrectly calculated.
The service life of wooden floors is very long, which contributes to the appearance of cracks and other types of destruction of tree species.

In order for everything to return to normal and in the future there are no deflections, they carry out such a manipulation as strengthening the lag, and in each case they approach the solution of the issue differently.

Strengthening the floor with overlays

It is possible to strengthen the logs by this method if a large number of cracks are found in wooden structures. The method is also suitable in case of a strong deflection of the floor. Working with wooden or metal overlays is considered simple, but reliable enough.

Attention! Reinforced logs can significantly increase the load on interfloor structures and operate them safely. It does not require tangible capital investments and large-scale repairs.

Nowadays, special carbon fiber is often used. But it can only be used if you are completely sure that the beam is not damaged by the fungus and there are ordinary cracks on the tree. In this case, in order to strengthen the lags, the damaged part is wrapped with fiber and fixed with adhesive.

The carbon fiber layer should be from 1 to 5 mm. Its value depends on the state of the crossbar and its future load.

How to strengthen lags with prostheses

As a prosthesis, a small steel truss is used, which is installed on a damaged section of a wooden beam. For its manufacture, a channel or metal bars are used. The first option is considered more reliable, since the part has standard dimensions, which simplifies the selection.

Attention! It is better to entrust the manufacture of a prosthesis from metal rods to a specialist competent in this matter, since a complex calculation is necessary here.

Very often, the logs are damaged in the area of \u200b\u200bthe beam, which is in contact with the wall. It is these areas that are most affected by changes in temperature and high humidity. In this case, wooden and metal prostheses are used for repair at the same time.

Reinforcement with prostheses is carried out according to the following scheme:

At the end of the work, the liner is fixed with nails. Sometimes the possibility of strengthening the beams is completely absent. In such cases, redistribution of the load on additional elements is used.

Install several supports that will support the logs from below.
They increase the number of logs by adding several new ones between the previously installed ones.

Such non-standard solutions can only be used in case of increased load. In this case, the lags themselves should not be damaged.

There are enough ways to reinforce the floors between floors so that, if necessary, you can choose the appropriate option. The main thing here is a responsible approach and reasonable calculation.

How to redo wooden floors: video

For modern technologies for the construction and repair of low-rise buildings, the use of methods for strengthening structures of the second floor is used quite often. Thanks to the accumulated experience and the use of new materials and technologies, many works, including strengthening the lag on the second floor, have become one of the ordinary operations of repair and restoration work. However, even with this seemingly looming simplicity, the process requires detailed study and calculation of literally all parameters and operations and the choice of the optimal method of carrying out the work.

Beams and logs: what is common and what are the differences between these concepts

In private low-rise housing construction, two-story houses are quite widespread. As a rule, these are houses of separate two- and three-story projects and buildings, converted by arranging an attic floor. In any case, in such houses, an interfloor ceiling is also equipped, and the flooring of the floors of the second floor is made.

For houses built with the use of frame-panel technology, and, in fact, for all other buildings, except for those where reinforced concrete slabs are used as interfloor floors, the basis of the structure is beams and floor logs.

beams used as load-bearing ceiling structures , the floor itself and the basis for installing the floor log. But lags- this is nothing more than beams of a reduced size, on which the plank flooring and the final floor of the second floor or attic are attached.

Floor beams are usually installed perpendicular to the internal load-bearing wall, the beams are supported by the external load-bearing wall of the house and the internal load-bearing wall or partition.

The lags of the second floor are laid perpendicular to the beams of the interfloor overlap. They can be laid directly on the beams or have an additional structure that forms an additional volume of interfloor overlap.

As beams commonly used:

Wooden solid beams;

Wooden type-setting beams;

Metal beams from a brand, channel, pipes or an I-beam;

Metal beams in the form of composite trusses;

Reinforced concrete beams from structures of different profiles;

As lag floors are commonly used:

Wooden beams;

Beams from glued structures;

Combined structures made of metal and wood;

Thus, despite the general similarity and the same principle of use in the building structure, beams and logs have different purposes, sizes and, accordingly, different, although in many respects similar methods of reinforcement.

In the classical case of using interfloor beams and the second floor floor lag, the structure will look like this:

Floor beams made of solid wood, rectangular in shape, without joints (the cross section depends on the span length - the width of the room) are the basis for the construction of the interfloor ceiling;
The ends of the beams are fixed in an array of opposite load-bearing walls and fixed with metal studs or on self-tapping screws and metal perforated fasteners;
On top of the beams, the floor lags of the second floor are installed. They are installed perpendicular to the beams at the same distance and have a shape and section that ensure reliable fastening of the finishing floor boards;
The space between the beams and joists is filled with insulation for noise and heat insulation of the premises.

Interfloor construction

In such a design, designed for a payload of 400-450 kg per 1 square meter, a deflection deformation of 1/300 of the beam length is considered natural. Simply put, with a beam length of 6 meters, the maximum deflection of the beam can be about 2 cm . If the beam is bent by a greater value, the structure requires additional reinforcement and strengthening.

The beams themselves withstand two types of load: the first is the static load from the weight of the remaining floor elements and the installed pieces of furniture and equipment on them. The second - dynamic load - arises from the movement of people on the floor surface of the second floor and the temporary installation of furniture in the central part, when the beams and logs have the greatest load.

Properly selected materials, their quality, and installation method, including the distance between beams and joists, help to withstand various types of loads and not succumb to deformation of the interfloor structure.

Dependence (in millimeters) of the sections of the lag and the steps between them on the thickness of the floorboards

It is considered optimal double-tee form of composite logs for the floor and composite form of beams for floor covering. At the same time, for any types of logs and beams, the main type of deformation that affects the entire structure of the house is the deflection in the central part. And that is why the reinforcement of beams and logs located in the center is most often carried out.

When you need to strengthen the lags

In construction practice, strengthening the lag of the second floor is used in several cases, most often at the stage of construction and reconstruction of the building. At the construction stage, it is easier and more convenient to make reinforcement, especially since several methods can be used for this, choosing the most suitable one from them. During reconstruction, reinforcement can be done after the complete or partial dismantling of the floor covering and insulation, while there are very few methods for installing additional structures.

Reinforcement work is usually carried out:

To prevent deformation of interfloor beams and floors of the second floor during the construction phase;

To correct defects made during the construction process and identified during the construction of the building;

To replace deformed or damaged by natural pests wooden structures of a building or structures made of other materials as a result of external factors.

To strengthen the lag when repairing the floor.

Methods and means of strengthening the structure in such cases are selected depending on the amount of work and the degree of deformation of the floor and the floor itself. In some cases, a simple strengthening of the lag will not have the desired effect without a significant amount of work to restore the beams, because, having leveled the floor of the second floor, sooner or later the ceiling of the first floor will have to be leveled.

When evaluating the floor, it is necessary to objectively assess its condition, because in many cases it is necessary to replace the deformed floor boards or level them, and not to strengthen the lag.

This method is applicable to reinforce the structure of the floor of the second floor, when the beams do not have a deflection, and the logs themselves, based on calculations, can withstand the calculated load. The essence of this method is to install additional logs in the central part of the room, thus ensuring the distribution of the load more evenly, on a larger number of supports.

Most often, the installation of additional logs is carried out in the center of the room by reducing the distance between the logs by 25-30%. So, if necessary, install logs after 0.5 meters, in the central part the distance is reduced to 0.4 - 0.35 meters.

For reinforcement, standard logs used in the design are used. For strength, additional spacers are installed between the lags from solid sections of boards or metal bar prostheses installed crosswise.

Bar metal prostheses to strengthen the lag

The method of installing additional overlays and strengthening the lag is possible both at the construction stage and during repair work. For logs made of timber, reinforcement is most often used with wooden linings and linings made of plywood or OSB boards.

Wooden linings are used:

To strengthen mechanically damaged sections of the lag;

To strengthen the junction or splice lag;

To create additional strength along the entire length of the log.

a, b, c - reinforcement of the lag with wooden overlays on bolts, d - reinforcement with a bar prosthesis

Linings made of OSB boards and plywood are mainly used at the points where the segments are joined to each other and in places where defects are visible or there are minor mechanical damages.

Metal plates can be applied to the places of damage and splices as a method of local solution of the problem.

Full reinforcement with overlays

Installation of overlays on the logs along the entire length is carried out by means of a bolted connection through the body of the overlays and the log, using self-tapping screws along the entire length, or by using a bunch of several bundles of mounting wire.

The installation of the overlays is carried out alternately with temporary fixation of the overlays with the help of clamps or self-tapping screws to the body of the log.

Holes are drilled in one line. The distance between the holes for the connection is usually not less than ¼ of the length of the log. Holes are drilled like this: one in the center, and from the edges at a distance of 1/3 of the height of the log from the edges of the log. This arrangement of holes will not allow the beams and logs to split along the length. Bolts must have washers on both sides - both under the bolt head and under the nut. The tightening is carried out gradually, until a significant resistance of the tree, and the final tightening is done alternately, starting with the extreme bolts. In this case, the tightening is done evenly by ¼ turn.

If the logs have fixing edges in a brick wall, a hole must be made so that the edges of the beams are also fixed in the wall. Treatment of additional beams with an antiseptic is carried out before installation on the logs.

If necessary, straighten the sagging logs, using wooden wedges or a conventional automobile hydraulic jack, pressing the log to the desired level.

Local reinforcement of joist structures is mainly used in places of junctions or splices of joists. To strengthen these sections, the method of installing overlays on one side or installing overlays on both sides of the beams is used. For the one-sided method, a tree without knots and visible damage is used, in which case the width and height of the additional element must be equal to the width and height of the log itself.

Partial reinforcement of the lag (on both sides) at the junctions of the lag

Fixation is carried out using bolts, screws and nails. The length of the element must not be less than the distance between the two beams of the interfloor overlap. Bolted connections are made through, while the washers should be 3 times wider than the nut and bolt head.

Strengthening the lag with a wooden lining

To fix the joist joint with double-sided pads, it is allowed to use a beam narrower than the joist. Usually boards with a width of 1/2 the width of the log are used for this. The length of the overlays is usually taken at least 1 meter. The screed is also done using bolts or self-tapping screws.

For logs made of glued material or structural wooden I-beams, linings made of plywood or OSB boards are most often used. Such overlays are also installed in the form of double-sided overlays or one-sided lag reinforcement. Fixing such a connection is carried out using self-tapping screws. The thickness of the plywood or OSB board element should be no less than 10-12 mm. The size of the overlay for a structural I-beam must correspond to the height of the central part.

Strengthening the log with plywood

Fixing with self-tapping screws is done on both sides of the lining. It is important that the screws go through the thickness of all fastened elements.

Metal linings used to strengthen the lag of houses on the second floor can be:

Piece elements made of perforated sheet metal with a thickness of at least 5 mm;

Made from a metal strip of various widths with a thickness of at least 5 mm;

From a shaped pipe of square or rectangular section with perforation or welded fasteners;

From a corner or brand.

piece elements from sheet metal are used to strengthen the joints of the lag. The sizes of such overlays can have both standard indicators, and selected depending on the specific case of the connection. Fixing for joints of beams of small height is carried out with the help of self-tapping screws, and if the logs have a height of more than 10 m, then with the help of a bolted connection. Metal plates are used for double-sided installation.

Strengthening the lag with steel sheets

metal strip usually reinforces logs of great length, while if the width of the strip used for installation is greater than or equal to 50 mm, then fixation can be either with self-tapping screws or with bolts.

Strengthening the lag with metal strips and channels on both sides

For logs that need to be strengthened along the entire length, they are used as structural elements shaped metal pipes square or rectangular section. The place of installation of such elements is the central logs of the premises, where defects are most clearly manifested. Pipes are simply fixed to the logs along the entire length on one or both sides. Bolts are used for screed reinforcement logs with a height of 80 mm or more. For a smaller lag, fixing is carried out using self-tapping screws.

Shaped metal pipes can be used to reinforce wooden logs

corners most often used for installation at the bottom of the log, reinforcing it from deflection from the underside. To do this, corners measuring 30 * 30, 45 * 45 or 60 * 60 mm are brought under the logs from below and fastened with self-tapping screws into the holes drilled in the corner.

Strengthening lags with corners

Taurus of various sizes can be attached both from the side and from the bottom of the log. The fastening method depends on the width and height of the log.

The use of metal for installing logs has found its application relatively recently. Basically, metal structures in low-rise construction are used as interfloor beams. At the same time, tees, channel bars and I-beams are quite often used as a base for fastening wooden elements and serve as excellent lags for a finished floor.

The nature of changes and deformations in such structures, as a rule, does not differ from wooden logs - the deflection in the central part of the room is also characteristic of metal elements.

Methods for strengthening such structures depend on what space can be used to install additional elements. If there are floor beams under the metal logs, then, in this case, the following methods can be used:

Installation of additional structures in the form of trusses;

Raising the sagging section and installing an additional support stand under it;

Installation of additional logs from a more stable form of rolled metal.

Installation additional structure in the form trusses from pipes, angles or fittings will ensure the rigidity and reliability of the lag. For this, trusses of a triangular or rectangular truss with diagonal stiffeners are used.

If it is possible to strengthen the place of deformation with a stand under the place of greatest deflection additional rack supported on a floor beam, then this method will provide the simplest and most effective method of reinforcement. True, it must be borne in mind that the floor beams must withstand the loads from such reinforcement.

How can I strengthen the lags of the second floor

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