Strengthen the genital lags. Strengthening wooden floors - ways to strengthen the ceilings and beams of the second floor

Currently exists great amount various construction manuals (" We build a house with our own hands", "How to build good house", etc.). They offer various materials and technology.

If we talk about family living, then the most the best option counts two-story wooden house. Wood is an environmentally friendly, healthy material, easy to process. It is used not only for building walls. Wood is a popular material for flooring. We'll talk about them in the article.

Lags

IN wooden house use beams or joists to construct floors. However, the latter are more popular. This is due to the fact that floor joists are much lighter than beams and are more mobile.

It is extremely difficult to move beams after installation, and repairs will be very expensive. Floor joists are easy to install, dismantle and repair.

Specifications

If we build a house with your own hands, you need to know some technical details. First of all, you should choose the right material in size. The table below shows the parameters (in millimeters) that should be followed:

Board thickness	Step between joists	span of room	Lag section

To better understand the calculations, consider an example. Let's say the length of the room is 10 m, and batten has a thickness of 30 mm.

In accordance with the data in the table, for such a thickness it should be 50 cm. For a room of a given length, 20 logs are needed. In this case, the distance from the wall should not be more than 30 cm. Accordingly, you need to add 1 more log to 20. The distance between the others will be 45 cm.

Important point

When calculating, rounding should be done downwards. This will provide an additional margin of safety.

There is no need to calculate distances to the nearest millimeter. As a rule, centimeters are used in calculations.

Grounds

Before how to do wooden floor , it is necessary to assess the condition of the foundation.

The logs can be laid on concrete, wood or ground. Each option has its own technological features which should be taken into account when performing work. In general, flooring technology remains virtually unchanged.

Wooden base: preparatory stage

It can be OSB boards or Under the future wood flooring You can lay insulation with vapor and waterproofing. Polystyrene foam or mineral wool is used.

Before how to make a wooden floor, it is necessary to take the dimensions of the room. The amount of material is calculated taking into account the parameters given in the table above. Next, materials and tools are prepared and markings are made.

At this stage, the main thing is not to rush. Mistakes made during preparation are extremely difficult to correct later.

Installation

Wooden logs begin to be installed from the wall (outer) ones. If the room already has a subfloor, then you can attach it directly to it. Fixation should be carried out using metal corners with perforation. These fasteners greatly facilitate the work and ensure the stability of the lag.

According to the mark, taking into account the size of the board that will be used subsequently, a log should be attached. Do not tighten the screws immediately until they stop. Adjustment may be required later.

After installing the wall elements, you can begin installing the intermediate ones. The step between them will depend on the thickness of the board. Typically the distance is 70 cm.

Alignment

It is necessary to stretch a rope between the wall joists. The remaining intermediate elements are installed at this level. The accuracy should be ± 1-2 mm.

There is no point in leveling with greater accuracy, since it will take quite a lot of time. The height difference can be removed later when finishing the front part of the wooden flooring.

Ventilated floors

They are mounted according to As a rule, this option is used in non-residential rooms.

When installing such floors, special precision is not required. Leveling is done directly with lags. Fastening is carried out using nails or self-tapping screws from the side of the beams. The scheme of actions does not differ from that described above.

Ventilation is carried out through special openings in the foundation. A distance of at least half a meter should be maintained between the floor and the ground. If it is less, the shortness of air exchange will not meet the required parameters. This, in turn, will negatively affect the condition of wooden structures.

Concrete base

The installation of a floor on it is associated with a number of difficulties. First of all, it is necessary to reliably protect the wood from rotting. For this, all kinds of impregnations are used. Meanwhile, structures impregnated with special compounds can hardly be considered environmentally friendly, but it is precisely because of this indicator that many use wood in construction.

If it is planned to install logs over the entire area, waterproofing must be laid between them.

To fasten the elements, the same metal corners. They provide a gap between the concrete and the joist. Of course, the load-bearing properties of the base will deteriorate somewhat.

Work progress

By concrete screed markings are made. Drill with Pobedit drill holes should be made for the corners. The distance will depend on the size of the lag.

The two opposite ends of the wooden element are set according to the level and marks, then they are attached to the corners. To check the position is used building level. Other lags should also be set according to it.

This installation option has a number of undoubted advantages. First of all, direct contact between wood and concrete is completely excluded. Secondly, with the help of corners you can remove unevenness up to several centimeters. Accordingly, there is no need to do a finishing screed before installation.

You can, of course, lay the logs directly on the concrete. In this case, a material based on modified bitumen is used as insulation.

Ground mounting

This method of laying logs is usually used in outbuildings, bathhouses, gazebos, etc. Wood must be treated with antiseptics. If you need to make it durable strip foundation, then you need to provide ventilation vents in advance. Usually a columnar base is used.

Before laying the logs, it is necessary to remove the fertile layer of soil. Next, the columns are marked. They can be made of concrete, prefabricated, block. The size of the supports is approximately 40x40 cm, the depth is 30 cm. Sand is poured onto the bottom in a layer of approximately 10 cm and compacted.

The next stage is pouring the supports with concrete. The mixture is prepared from a ratio of 1 part cement to 3 parts sand and 2 parts crushed stone. It is not necessary to make formwork in the ground. Formwork made from scraps of OSB or boards is fixed above the ground. When constructing it, a level must be used. The edges of the formwork must be vertical.

The easiest way to make columns is from blocks. They are leveled horizontally using a rope. After installing the outer posts along the hydraulic level, you should pull a rope between them. It is necessary to ensure that the deviations are not more than ± 1 cm. This difference can then be eliminated when installing the log.

Installation Features

Laying also begins with the outermost joists. Precise horizontal alignment can be achieved using shims. It is not recommended to use wooden wedges as they will shrink over time and wobble will appear: the floor will creak while walking.

Between wooden elements and concrete surfaces Roofing felt is laid in 2 layers. This will ensure reliable protection from moisture.

After installing the outermost joists, the installation of the rest begins. Alignment is carried out along the rope. Fixation is carried out using metal corners and dowels with self-tapping screws. You can increase stability by installing fasteners on both sides.

The boards can be laid directly on the joists or on the subfloor.

Coniferous wood is considered the best option.

You need to select logs with a margin of safety. This is especially true if it is planned to install an interfloor wooden floor. In such cases, the elements will bear increased bending load.

It must be remembered that the mistakes that were made on preparatory stages, fixing it later is much more difficult: you will have to spend not only time, but also money. Therefore, it is more advisable to immediately choose quality materials and follow the recommendations.

When choosing lags, it is necessary to evaluate their condition. The wood should not show signs of rotting, through cracks, or knots.

Consequences of errors

As mentioned above, failure to comply with the technology can lead to wobbly boards. And if it is still possible to correct such errors on the ground floor, albeit at a financial cost, then repairs second floor ceilings- a real problem.

In many houses, especially older ones, you can notice the deflection of the ceiling with the naked eye. This situation is due to incorrect calculation bearing capacity structures or exceeding the maximum load.

The amount of lag deflection depends on various factors:

• Quality of the material.
• Wood moisture level.
• Insufficient thickness of metal elements.

These, of course, are not all the reasons. In some cases it is laid under load.

It should be said that in any case, sagging ceilings can have the most Negative consequences. Incorrect calculation of the load can lead not only to deflection wooden elements, but also to the complete collapse of the second floor in a wooden house. And this happens, as a rule, when no one expected it.

When should action be taken?

Which one needs to be carried out? preparatory work, before How to strengthen the second floor joists? Can strengthen the ceiling if obvious sagging of the ceiling is detected. In this case, the first thing that needs to be done is to take measurements, assess the condition of the structural elements, and determine the static load indicator. Using these parameters, the amount of sagging is determined.

Any ceiling, under the influence of its weight, the static load of objects and structures installed on it, bends over time. The acceptable sag value is 1:300. For example, if a beam 3 m long has bent by 10 cm, there is nothing to worry about yet. However, if the value is greater, you need to carry out strengthening of structures and get rid of deformations. Next, we'll look at several ways to fix the problem.

How can you strengthen the second floor joists?

Methods for strengthening wooden structures vary depending on the condition of the elements. Everything can be found in construction stores.

First, enough in a simple way The use of timber overlays is considered. The width of the beam is subtracted from the cross-section of the log. The elements are fastened with bolts with metal plates, which prevent the destruction of wood in the connection area.

The bent log is raised to the required level, after which the timber lining is fixed to it.

Metal strips

Their thickness should be 10 mm, and their width should be 10-20% less than the height of the logs.

Bolts should be used for fastening. At the same time, to increase the strength of the structure and prevent deformation of the strip, it is advisable to increase their number.

Overlays can be installed on one or both sides at once. This will depend on the load on the load-bearing parts of the floor.

Other metal products

How can you strengthen the second floor logs? if they are damaged by putrefactive bacteria or insects?

To strengthen the elements, “prostheses” are used, welded from a rod in the form of a spatial truss or using a channel.

In the first case, a rather complex calculation of the strength indicator is required. It can only be carried out qualified specialist. The channel can be selected from standard rolled metal products.

Additionally

Strengthening interfloor structures can be done by installing additional logs. However, such work will require adding holes in load-bearing walls. In some cases, making them is very problematic.

When using metal elements to strengthen the logs, it is necessary to provide for the installation of elements to which the boards will be attached. They must be reliable and durable, eliminating wobble. This is especially true for floors with damaged parts.

Use of carbon fiber

It's comparative new way lag reinforcement Carbon fiber is glued in several layers until the required rigidity of the log is achieved.

This material is presented on the market in the form of fabric, threads, plates, tapes, sheets. Carbon fiber (CFRP) is very convenient to use. One of its advantages is its light weight.

Installation of a rod “prosthesis”

To manufacture this element, two paired trusses are used. They, in turn, are made from scraps of reinforcement with a cross-section of 10-25 mm. The length of the product must exceed twice the length of the damaged end of the joist by 10%, but be no more than 1.2 m.

Installation is carried out as follows:

• Temporary supports are installed in increments of 1-1.5 meters from the load-bearing wall. The supports are racks with purlins.
• The damaged section of the joist is cut off.
• The “prosthesis” blank is inserted vertically into the interfloor ceiling and turned over horizontally. First it is pushed onto the log, then into reverse side and push it into the wall niche.
• The sliding bar is moved to the required distance and fixed.

Other solutions

Before how to strengthen the logs of the second floor, you can check if it is possible to unload them, that is, distribute the load among other elements.

For example, you can use supports or install additional logs. The first option, however, is not always possible to implement. The fact is that the supports will take up space and can create inconvenience when moving around the room. But some craftsmen turn them into decorative element interior

As for installing additional logs, as mentioned above, this is not always possible due to design features building. If conditions allow, then it is better to add several elements to it. This is especially true in the case when the existing logs are not damaged. In this case, the ends of the new elements must be protected with roofing felt before installation.

Alternative material

At the very beginning of the article it was said that for the construction of floors it is more advisable to use logs due to their mobility and lightness. This recommendation can be used if the expected load on the structure is small.

But what to do if the load indicator is high? You can deal with the problem using wooden I-beams. Outwardly they look like rails.

Scope of use

Wooden I-beams used in private construction. In low-rise buildings, these elements are used as load-bearing structures in interfloor ceilings.

I-beams perfectly replace boards, metal profiles, reinforced concrete slabs. They are able to more than triple the rigidity of walls. The result is a more stable structure without a significant increase in weight.

Characteristics

For the manufacture of I-beams, glued laminated timber and particle board are used. The photo above shows the design features.

Among the features of the I-beam are the following:

• The plywood used for the side posts is moisture resistant. The thickness of the plate can be different: from 24 to 27 mm. The I-beam contains wooden shelf, treated with an antiseptic.
• Inserting a stand from particle board carried out using special technological grooves.
• The parts are fixed to each other using water-heat-resistant glue.
• The outside of the I-beam is coated with water-repellent paint.

The following dimensions are considered the most common: dimensions - 200x80 mm, lintel thickness - 27 mm.

Advantages

First of all, it should be noted good combination materials: wood - slab - wood. The design does not have the disadvantages inherent in natural wood.

The I-section acts as a kind of amplifier: due to it, the strength of the jumper increases several times. These features make it possible to place the I-beam on a par with concrete and metal floors. At the same time, beams have a significant advantage over the latter, since they are completely not susceptible to corrosion.

When installed in accordance with the technology, the floor will not creak. does not bend, unlike logs and other wooden materials.

Despite the operational power, the weight of the jumper is relatively light. Installation of structures can be done with your own hands. Installation of I-beams can be carried out by 2-3 workers. The weight of the product with a length of 6.5 meters does not exceed an average of 40 kg. Accordingly, the foundation of the building will not be under high load.

I-beams are not subject to drying out. Due to High Quality manufacturing, deformation of the beam is practically eliminated. In addition, the elements do not shrink, swell, or twist under the influence of climatic factors.

The ability to retain heat is of no small importance. Beams have low thermal conductivity, which helps reduce cold bridges.

For the manufacture of I-beams it is used the latest equipment and advanced technologies. The products fully comply with international and national quality standards. At the factory, beams are treated not only with an antiseptic, but also with a fire-fighting compound.

I-beams can be used in low-rise buildings of any type, including frame, block houses. Mounting can be done using any accessible ways. As a rule, metal fasteners, screws, bolts, angles, and brackets are used.

As you can see, beams are an excellent alternative to joists. Having installed them, the home owner will not worry about sagging ceilings and creaking floors.

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

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

When to strengthen wooden floor beams

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

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

• the need to increase the load-bearing capacity of the beam. Associated, for example, with the reconstruction of an 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 methods of strengthening the ceiling will be given (reconstruction). But only a professional can accurately answer the question of how to strengthen wooden floor beams and only after analyzing the condition of the structure. After all, in each case the decision will be individual.

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

Material prepared for the website website

Ways to strengthen wooden floor beams

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

Type of amplification without changing operating conditions

Reinforcement with wooden overlays

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

Reinforcement of spans with metal plates (plates) or rod 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 device diagram is shown in the figure.

Reinforcement of flooring with carbon fiber (carbon fiber reinforced plastic)

Modern reinforcement technology (carbon fiber reinforcement). Carbon fiber (strips, sheets, plates, threads, fabric) is glued in several layers until the required beam stiffness is achieved. Ease of use and lightness of the material lead to the fact that carbon fiber is gaining popularity as effective remedy for 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 you to strengthen the beam at the junction with the load-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 made of channel, rolled profile

Installation of a rod prosthesis

The bar prosthesis of the Deidbekov system is made of 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% greater than twice the length of the rotted end of the beam, but not more than 1.2 m.

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

Type of amplification with changing operating conditions

Strengthening wooden floors using these methods requires significant reconstruction. load-bearing structure 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.

Strengthening 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 intact and intact, their load-bearing capacity can be increased 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 felt to avoid damage.

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

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

What are wooden logs

Cross beams are logs that are mounted on bricks or a reinforced concrete base. Made from solid timber made from square or round section. To save money, some owners make them from jointed boards installed on edge.

Floors arranged on wooden blocks

Advantages of using flooring on wooden blocks

• With the same lifting height, floors organized using transverse beams have much lower structural weight, for example, when compared with monolithic concrete ones.
• The floor, organized in a similar way, is well ventilated.
• Hidden communications can be installed between the flooring beams.
• A floor that has an undivided space under the flooring can in addition be thermally insulated and soundproofed.
• Floors of this type can be leveled even if they have a large difference in height.
• A floor of this type can be easily dismantled for reconstruction.

In order for the floors to be reliable and last 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, similar situations arise when 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 wooden elements from which the floor was made by fungal diseases or due to damage by rodents;
• exceeding the load-bearing capacity for which the floor was originally designed;
• the first erroneous calculation of the cross-section of wooden elements, etc.

Attention! It is allowed for the floor 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 strengthening the cross beams. Let's look at some of them.

We strengthen the floor by reinforcing wooden structures with overlays

This is done if cracks are found in wood structures or the floor begins to bend too much.

Before carrying out work, you need to unload the floors, and you may also need to dismantle the covering. Unloading the structure is done by installing non-permanent racks made 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 beam is made of solid logs, it is permitted to install a single post at the point of deflection. If the structures are composite, then it is necessary to install several racks. In the place where the floors sag, install a jack, and with its help bring the system into a horizontal position.

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

The trim is placed on one or both sides and is sewn to the legacy system using bolts with iron backings. They are necessary in order to eliminate the destruction of wood under load at the attachment point.

To improve the floor, replace wood overlays iron can be used. IN this option metal strips with a thickness of 10 mm and a width 10–20% less than the width of the cross beam are used. As in case wood overlays, iron mounted on one or two sides structural element, only the number of fastening elements is increased by approximately 25%. The metal is treated with anti-corrosion compounds before installation.

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

Gain beams using wood overlays

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

In this option, the damaged part is wrapped in carbon fiber, which is secured using a specialized adhesive made from an epoxy-based resin. Similar material allows you to improve the design without increasing the thickness of the reinforced element. A 1–5 mm layer of carbon fiber is wound where needed, depending on the planned load and the condition of the beam.

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

Gain wooden beams using prosthetics

If the timber is damaged by fungus or insects, the floors can be repaired by strengthening the structure with prosthetics. The prosthesis is a specialized small iron truss, which is placed to replace the damaged area.

Prostheses are made from channel bars or welded using iron rods. For repair work on our own in this option, it is better to use a channel, since it is made in standard sizes, and you only need to choose the appropriate prosthesis. Thanks to its own shape, the channel perfectly withstands existing floor loads.

Attention! To produce a prosthesis from iron rods, you need to make a rather complicated strength calculation, and therefore it is recommended to entrust this matter to a professional.

To improve floors, use prosthetics made from a channel or metal rod

Damage often occurs in that part of the beam that rests on the surface of the wall, because it is here that the transverse beams are susceptible to sudden temperature fluctuations and very high humidity. If this part of the structure is damaged, then fix the 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 overlays are selected so that the total thickness of the structure is slightly greater than the thickness of the original structure. An insert is placed between the pads. The liner is attached to the linings using nails.

Gain structures using wood prosthesis

We strengthen the floors between floors

To fix the floors, which are located between floors, can be found from below install auxiliary supports that will take part of the load on themselves. In this option, the floors can bear a high load.

• install auxiliary intermediate beams. This will also give an opportunity fix the floors.
• If possible, you can install auxiliary intermediate cross beams.

If it is not possible to improve the timber using the methods listed above, then you can unload the structures by redistributing the load to additionally installed parts.

One of the main structural elements used for the construction of floors in attics or second-floor rooms, mainly in low-rise buildings individual construction, is wooden or metal beam, which simultaneously serves as a floor joist and a base for fastening ceiling coverings. Widespread beam floors contributed to the low cost of the initial building materials and the possibility of constructing floors without the use of lifting mechanisms.

Lag deflection

Often the degree of deflection of the joists depends on the installation technology and the quality of the material.

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 a consequence of incorrect calculation of the load-bearing capacity of the joists or excess permissible load on the floors. As operating practice calls multi-storey buildings buildings of the first half of the 50s of the twentieth century, where wooden interfloor ceilings were used, by 2000 the ceiling deflection ranged from 70 to 100 mm, which led to the need for major repairs buildings with reinforcement of load-bearing floor elements. 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 development, when the calculation of the load-bearing capacity of the logs was carried out “by eye” on the advice of “competent” specialists.

Very often, the quality of the material used also influences the amount of deflection of the logs, excess humidity wood, insufficient thickness of the rolled metal from which the beam is made, and many other different reasons leading to sagging, for example, of the second floor floor under load. An incorrect calculation of the load-bearing capacity can lead not only to the deflection of the log, but also to the complete destruction of the structure and the collapse of the floor downwards, and when no one expects this.

When is it necessary to strengthen the logs?

Scheme of interfloor wooden floor arrangement

If the owner of the house notices sagging of the upper floor, then the first thing that needs to be done is to take simple measurements and assess the condition of the structures, the magnitude of the static load in order to determine the amount of sagging of the ceiling or changes in the curvature of the floor to decide on the need to strengthen the logs.

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

Strengthening metal structures

Metal structures used as beams interfloor covering, can be strengthened with additional rolled metal products using welding or bolting. To do this, the surface of the floor or ceiling is dismantled, 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 cross-section, the calculation of which is carried out using special tables and methods.

Strengthening wooden elements

An example of reinforcing a joist with a wooden overlay

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

1. Using timber overlays, performing a simple mathematical calculation, when table value the cross-section of the required floor beam is subtracted from the width of the existing beam. The timber and the beam are fastened using bolts with metal plates that prevent the destruction of the wood at the fastening point and weakening of the structure. The existing beam is raised with jacks until a level floor surface is obtained, after which the overlay and the beam are fastened together;
2. Using metal strips with a thickness of 10 mm and a width 10-20% less than the height of the beam as overlays. To prevent the strip from deforming and reducing strength, the number of fastening bolts should be increased by 25% compared to wooden elements. Overlays are installed on one or both sides of the beam depending on the load on load-bearing elements floor of the upper floor;
3. Wooden floor beams damaged by insects or putrefactive bacteria can be strengthened using prosthetics welded from a rod in the form of a spatial truss, or using a channel required size. The channel installed as a prosthesis is selected from a standard range of rolled metal, and to manufacture a spatial rod truss it is necessary to perform a rather complex strength calculation, which only a qualified specialist can do.
4. Strengthening the load-bearing capacity of interfloor structures can be done by installing an additional number of beams, but this work requires making holes in the load-bearing walls, which in some cases is difficult to do.

Reinforcement of logs with metal strips

Using metal elements To strengthen the load-bearing interfloor structures, especially for destroyed parts that need 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, eliminating the possibility of loosening and squeaks.

Reinforced different ways logs make it possible to increase the load-bearing capacity of load-bearing interfloor structures and the overall safety of operation of existing buildings without significant capital investments and a large amount of construction work.

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 joists

Logs are transverse beams that are installed on bricks or a reinforced concrete base. Made from solid wooden beam square or round. To save money, some owners make them from spliced ​​boards mounted on edge.

Floors organized on logs

Advantages of using decking on joists

• At the same lifting height, floors organized using joists have a much lower structural weight, for example, compared to reinforced concrete ones.
• The floor, organized in this way, is well ventilated.
• Hidden communications can be installed between the flooring beams.
• 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 last 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, situations arise when floors need to be reinforced. This happens in the following cases:

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

Attention! It is allowed for the floor to have a deflection of 1:300. That is, 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 ways to strengthen the lag. Let's look at some of them.

We strengthen the floor by reinforcing wooden structures with overlays

Executed if wooden structures Cracks are found or the floor has begun to sag significantly.

Before carrying out work, it is necessary to unload the floors, and it may also be necessary to dismantle the covering. Unloading the structure is carried out by installing temporary racks made 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 solid log, it is allowed to install a single post at the point of deflection. If the structures are composite, then you need to install several racks. In the place where the floors sag, install a jack, and with its help bring the system into 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 required diameter. Next, the diameter of the beam is subtracted from the desired value. The resulting value will give us minimum thickness overlay, which is used to build up the beam.

The overlay is installed on one or both sides and stitched to the old structure using bolts with metal backings. They are needed to prevent the wood from collapsing under load at the attachment point.

To strengthen the floor, you can use metal overlays instead of wooden ones. In this case, metal strips with a thickness of 10 mm and a width 10–20% less than the width of the log are used. As in the case of wooden overlays, metal ones are installed on one or both sides of the structural element, only the quantity fastening elements increase 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 area with antifungal compounds. The linings themselves are also treated with an antifungal compound.

Reinforcing beams with wooden overlays

Reinforcement can be done using 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 in carbon fiber, which is fixed using a special adhesive composition made on the basis epoxy resin. This material allows you to strengthen the structure without increasing the thickness of the reinforced element. A 1–5 mm layer of carbon fiber is wound onto the desired location, depending on the expected load and condition of the beam.

Once finished renovation work, the supports are removed.

Strengthening wooden beams using prosthetics

If the timber is damaged by fungus or insects, then the floors can be repaired by strengthening the structure with the help of prosthetics. The prosthesis is a special small metal truss that is installed in place of the damaged area.

Prostheses are made from channel bars or welded using metal rods. For repairs on your own, in this case it is better to use a channel, since it is produced standard sizes, and you just need to choose a suitable prosthesis. Thanks to its shape, the channel perfectly withstands existing floor loads.

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

To strengthen the floors, prosthetics made from channel or metal rods are used

Damage often occurs in the part of the beam that rests on the wall, since it is in this place that the logs are exposed to sudden temperature fluctuations 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 to strengthen the structure, the damaged element is supported with supports. The damaged area is cut out. The cut is treated with antibacterial compounds.

Next, wooden overlays 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 pads. The liner is fixed to the linings using nails.

Strengthening the structure with wooden prosthesis

We strengthen the 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 upon themselves. In this case, the floors will be able to bear a greater load.

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

If it is not possible to strengthen the beam using the above methods, then you can unload the structures by redistributing the load to additionally installed elements.