Draft floor on wooden beams: purpose and design features. Overlapping the floor on wooden beams: features of the floor device Alignment with metal profiles and drywall

16.06.2019

There are a few basic tasks that need to be done in order to have a level and solid floor laid in joists. This is the exact setting of the lag in one horizontal plane, their secure fastening to base, processing protective compounds, plus waterproofing of the entire structure. Before you align the logs under the wooden floor, you must correctly select them according to the section. Because this indicator affects the reliability and strength of the entire structure. If the house is being renovated, and the logs have already been installed, it is recommended to open the floors and check the beams for their quality condition. If necessary, some of them are replaced with new ones.

The appearance on the market of new floor coverings, which required a very flat surface when laying, replaced the technology of building floors on logs. They were replaced by screeds filled with cement-based solutions. This simplified the process of leveling the base for finishing, but this technology also had several drawbacks. One of them - it took a long time to wait until the screed dries. And this could take several days.

Modern technologies for the production of lumber have returned the method of constructing the floor along the logs due to correct geometry manufactured products, through the use of dry wood. Protective impregnations came to their aid, which penetrated into the wood, increasing its service life and preventing deformation under loads. Due to new technologies, manufacturers began to produce improved inexpensive materials for decking on logs. This is not only plywood, I would like to note OSB boards. With the help of durable and even sheet and panel materials, it became possible to lay laminate, linoleum, and ceramic tiles on the floor along the logs.

We must pay tribute to the fact that wooden construction has again become fashionable. More and more customers are giving preference to construction wooden houses. And in such houses, wooden floors look harmonious. Although the logs for the construction of the floor are used not only in wooden structures. Today they are also used in city apartments, especially on the ground floor, when the task is to insulate the floors.

But this design also has its drawbacks.

Even wood floors treated with flame retardants are still combustible structures.
They can not lay the heating system underfloor heating.
When installing logs in apartments, be prepared for the fact that the height of the ceilings will decrease.

Design features of the installation

If we are talking about installing a log in a city apartment, then there is only one location and alignment option - this is laying on a concrete floor slab, which is poured from above concrete screed. In principle, a fairly even surface is already obtained, but one hundred percent evenness is still far away. Therefore, the lags in the apartment will still have to be leveled.

In houses, floors are built in three ways:

On the ground. Up to the upper edges of the foundation, backfilling is done in several layers of different materials: crushed stone, sand, clay. All this is rammed, a screed is poured on top. On it, the installation of the lag is carried out. As an option, the logs are aligned with the foundation and completely filled up. Only their upper ends remain on the surface, to which the flooring is fastened. In this case, it is better to backfill with sand, and wooden elements before installation, it must be treated with protective equipment.
On the foundation on the supporting posts or without them.
By load-bearing beams.

Leveling the lag in the apartment

First of all, it is necessary to determine the most high place On the floor. Usually this is either the corner of the room, or one of the edges against the wall. Therefore, we measure the height of the ceiling in each corner of the room. The smallest size is the required space. Now, from this corner to the others, a liquid building level is stretched from a transparent vinyl chloride tube, which is filled with water, and an air bubble is left inside. If the bubble rises to the indicated corner when the level is set, then the assumptions were confirmed - this corner of the room is the highest. The same can be done with the midpoints of the floor edges mating with the wall surfaces.

Now a log is installed on the floor, one end of which is located in the selected corner of the room. Distance from the wall - 5 cm in the middle of the longitudinal axis.
The opposite end is raised so that a short level, laid on a log, shows the evenness of the installation. That is, the air bubble in the chamber should stop in the middle.
A lining is inserted under the raised end, pre-cut from a bar or plywood. There may be several gaskets, it all depends on the magnitude of the plane difference.
The lag stands horizontally. It can be fixed to the floor, for example, with metal corners.

Now you need to install another lag element at the opposite wall and align it horizontally and in the same plane with the one already installed. Depending on the width of the room, you can use either a flat wooden lath, or a long two-meter rule. One of their ends is installed on top of the laid log in the corner of the room. You can start from either end. The rule is set to the horizon, which will show an air bubble. A lag is laid under its free end, at the end of which linings are placed. The same is done with the other end. After that, the lag is attached to the floor.

So, two logs are installed and fixed at opposite walls. Now between them it is necessary to stretch several threads (4-5 lines), which will indicate the horizontal plane. The threads are fastened along the upper ends to nailed nails. Now intermediate logs are installed along the threads, under which pieces of plywood or wood are placed. The main requirement is that the threads must touch the upper ends of the log.

Manufacturers today offer adjustable designs with which you can easily set the logs. These are metal or plastic devices that are attached to the floor with dowels or anchors. Bars are installed on them, which can be raised or lowered with the help of threaded connection. Using this leveling option, you can not carry out complex measuring operations to determine the highest point on the floor.

Instead of adjustable structures you can use ordinary anchors, which are screwed into the concrete base gender. A nut is screwed on them, a wide washer is installed on top. A lag is put on, on top of which a wide washer is installed and a nut is screwed on. In fact, it is all the same adjustable device.

Alignment with foundation and load-bearing beams

The operation of leveling the lag along the foundation and along the beams is carried out in the same way. But there are also differences.

By foundation

Usually, the ends of the logs rest on the foundation, which is the basis for the floor. It is not always poured evenly, so the logs have to be set in the same plane along the horizon. Here everything is done almost exactly the same as in the apartment.

Two logs are installed at opposite walls.
Each of them is aligned horizontally using a building level with plywood pieces lining under the ends.
Threads are stretched between their ends, which in turn are checked for a difference. That log, which will be higher in height, will be the main one, that is, Starting point in the process of leveling all other lag elements. It must be immediately fixed to the foundation and to the walls of the house.
The ends of the second extreme log are exposed along the stretched threads, which is also immediately fixed.
A few more threads are stretched between the bars, defining a horizontal plane. According to them, intermediate elements of the lag structure with plywood or wood lining are exposed.

If the distance between the edges of the foundation is large, then support posts are built between them, against which the beams rest. The main requirement for the construction of supports is to precisely fit them in height so that the logs lie tightly on them. If this cannot be done as accurately as possible, then linings are placed under the bars.

On load-bearing beams

The design of the floor on the bearing beams is considered very reliable. Large-section beams or logs are installed on the foundation or ceiling, on which the logs are mounted. There are two options for leveling the floor structure.

Beams are aligned.
The lags are aligned.

It is more difficult to align with logs, because this lumber is uneven in cross-sectional geometry along the entire length. Therefore, the craftsmen try to process the upper and lower planes with a planer in order to give it the appearance of a plane. In this regard, it is better to use timber, because it is a rectangular material that manufacturers today produce with accurate geometry.

First, two beams are laid at opposite sides.
They are set on the horizon with a level, placing pieces of plywood, but metal plates are better.
Then they are aligned in the same plane with each other, as described with lags along the foundation. That is, the log located above is left in place. Additional metal elements are placed under the second.
After that, intermediate beams are set along the stretched threads.
And already on the beams without alignment, the logs are laid and fastened.

Alignment of the lag along the beams is carried out in exactly the same way. This option is easier in terms of the fact that it will not be necessary to lift heavy logs and beams to put plates under them. First, the logs are installed across the beams. That is, the logs are mounted on a large number of supports. Secondly, the beams themselves are a reliable and solid foundation. Therefore, choosing a lag section, you can stop at beams of a small section, such as those used to build floors in apartments.

The alignment process itself is carried out in exactly the same way as in the apartment. With only one digression - logs can be attached to beams or self-tapping screws directly, since both elements are wooden, or using metal corners. Otherwise, the installation technology is the same.

During the construction of private low-rise houses made of wood, concrete blocks or bricks, most often they erect between floors wooden floors. These designs, compared with alternative concrete slabs, have a number of advantages. Wooden floors do not overload the walls; during installation, they do not require the involvement of lifting equipment. In addition, they have high strength, durability and reasonable price. Installation of such ceilings is quite simple, so many home craftsmen perform it on their own.

floor structure

The basis of the wooden floor is the beams that are held on the load-bearing walls and serve as a kind of "foundation" for the rest of the structural elements. Since the beams during the operation of the floor will bear the entire load, special attention should be paid to their competent calculation.

For beams, massive or glued beams, logs, and sometimes boards (single or fastened in thickness with nails or staples) are usually used. For floors, it is desirable to use beams made of coniferous species (pine, larch), which are characterized by high bending strength. Hardwood beams work much worse in bending and can deform under load.

Draft boards (OSB, plywood) are fixed to the floor beams on both sides, on top of which the front cover is sewn. Sometimes the floor of the second floor is laid on logs, which are fixed on the beams.

It is worth remembering that the wooden floor from the side of the first floor will be the ceiling, and from the side of the second floor (attic, attic) - the floor. Therefore, the upper part of the ceiling is sheathed with floor materials: grooved board, laminate, linoleum, carpet, etc. The lower part (ceiling) - clapboard, drywall, plastic panels, etc.

Due to the presence of beams, space is formed between the draft boards. It is used to give the overlap additional properties. Depending on the purpose of the second floor, heat-insulating or sound-proofing materials are laid between the floor beams, protected from moisture by waterproofing or vapor barrier.

In the event that the second floor is a non-residential attic that will not be heated, thermal insulation must be laid in the floor structure. For example, basalt wool (Rockwool, Parock), glass wool (Isover, Ursa), polystyrene, etc. A vapor barrier film (glassine, polyethylene and polypropylene films) is laid under the heat-insulating layer (from the side of the first heated floor).

If EPPS, which does not absorb water vapor, was used as thermal insulation, the vapor barrier film from the “pie” can be excluded. A layer of waterproofing film is laid on top of heat-insulating or sound-proof materials that absorb and can deteriorate from moisture. In the event that during the finishing the possibility of atmospheric moisture entering the attic was excluded, the insulation can not be protected by waterproofing.

If the second floor is planned as a heated and living space, then the “pie” of the floor does not need additional thermal insulation. However, in order to reduce the impact of noise that will occur when people move along the floor, a soundproof layer is laid between the beams (usually the usual heat-insulating materials are used).

For example, basalt wool (Rockwool, Parock), glass wool (Isover, Ursa), polystyrene foam, ZIPS sound-absorbing panels, soundproof membranes (Tecsound), etc. When using materials capable of absorbing water vapor (basalt wool, glass wool), a vapor barrier film is laid between the first floor and the sound insulator, and waterproofing is placed over the sound insulator.

Fastening beams to the wall

Floor beams can be connected to walls in several ways.

in brick or log houses the ends of the beams lead into grooves ("nests"). If beams or logs are used, then the depth of the beams in the walls should be at least 150 mm, if the boards - at least 100 mm.

Parts of the beams in contact with the walls of the "nest" are waterproofed by wrapping them with two layers of roofing material. The ends of the beams are cut at 60 ° and left uninsulated to allow free "breathing" of the wood.

When inserting into the "nest", between the beam and the wall (on all sides), ventilation gaps of 30-50 mm are left, which are filled with thermal insulation (tow, mineral wool). The beam is supported on the base of the groove through an antiseptic and waterproofed wooden plank 30-40 mm thick. Sides the groove can be covered with rubble or covered cement mortar by 4-6 cm. Every fifth beam is additionally fastened to the wall with an anchor.

AT wooden houses beams are buried in the grooves of the walls by at least 70 mm. To prevent the appearance of squeaks, a waterproofing material is laid between the walls of the groove and the beam. In some cases, beams are cut into walls, making dovetail joints, etc.

Also, the beams can be fixed on the wall using metal supports - steel corners, clamps, brackets. They are connected to walls and beams with self-tapping screws or screws. This fastening option is the fastest and most technologically advanced, but less reliable than when beams are inserted into the grooves of the walls.

Calculation of floor beams

When planning the construction of the floor, first you need to calculate the design of its base, that is, the length of the beams, their number, the optimal section and the spacing. This will determine how safe your floor will be and what load it can withstand during operation.

Beam length

The length of the beams depends on the width of the span, as well as on the method of fastening the beams. If the beams are fixed on metal supports, their length will be equal to the width of the span. When embedded in the grooves of the walls, the length of the beams is calculated by summing up the span and the depth of inserting the two ends of the beam into the grooves.

Beam spacing

The distance between the axes of the beams is kept within 0.6-1 m.

Number of beams

The calculation of the number of beams is carried out as follows: they plan to place the extreme beams at a distance of at least 50 mm from the walls. The remaining beams are placed evenly in the span space, in accordance with the selected interval (pitch).

Beam section

Beams can have a rectangular, square, round, I-section. But the classic option is still a rectangle. Frequently used parameters: height - 140-240 mm, width - 50-160 mm.

The choice of the beam section depends on its planned load, the span width (on the short side of the room) and the spacing of the beams (step).

The load of the beam is calculated by summing the load of its own weight (for interfloor floors - 190-220 kg / m 2) with the temporary (operational) load (200 kg / m 2). Usually, for operating floors, the load is assumed to be 350-400 kg / m 2. For non-operated attic floors, you can take a smaller load, up to 200 kg / m 2. Special calculation is necessary if significant concentrated loads are expected (for example, from a massive bath, pool, boiler, etc.).

Beams are laid along a short span, the maximum width of which is 6 m. On a larger span, sagging of the beam is inevitable, which will lead to deformation of the structure. However, in this situation there is a way out. To support the beams on a wide span, columns and supports are installed.

The cross section of the beam directly depends on the width of the span. The larger the span, the more powerful (and durable) the beam must be chosen for overlapping. The ideal span for overlapping with beams is up to 4 m. If the spans are wider (up to 6 m), then non-standard beams with an increased cross section must be used. The height of such beams should be at least 1/20-1/25 of the span. For example, with a span of 5 m, beams with a height of 200-225 mm should be used with a thickness of 80-150 mm.

Of course, it is not necessary to independently perform beam calculations. You can use ready-made tables and diagrams that indicate the dependence of the dimensions of the beams on the perceived load and the width of the span.

After performing the calculations, you can proceed to the overlap device. Consider the whole technological process, starting with fixing the beams on the walls and ending with the finishing sheathing.

Wood flooring technology

Stage #1. Installation of floor beams

Most often, beams are installed with their introduction into the grooves of the walls. This option is possible when the installation of the floor is carried out at the stage of building a house.

The installation process in this case is as follows:

1. Beams are covered with antiseptics and flame retardants. This is necessary to reduce the tendency wooden structures to decay and ensure fire safety.

2. The ends of the beams are cut at an angle of 60 °, they are crumbled bituminous mastic and wrapped with roofing felt in 2 layers (for waterproofing). In this case, the end should remain open, for the free exit of water vapor through it.

3. Installation begins with the installation of two extreme beams, which are placed at a distance of 50 mm from the walls (minimum).

The bars are inserted into the "nests" by 100-150 mm, leaving a ventilation gap between the wood and the walls of at least 30-50 mm.

4. To control the horizontalness of the beams, a long board is installed along their upper plane on the edge, and on top of it - bubble level. To align the beams in level, wooden dies of different thicknesses are used, which are placed in the lower part of the groove on the wall. Dies must first be treated with bituminous mastic and dried.

5. To eliminate the creak of the beam and block the access of cold air, the gap is filled mineral insulation or tow.

6. On the laid control board lay out the rest, intermediate, beams. The technology for inserting them into the sockets of the walls is the same as for the installation of the extreme beams.

7. Every fifth beam is additionally fixed to the wall with an anchor.

When the house is already built, it is easier to install floor beams using metal supports. In this case, the installation process is as follows:

1. Beams are impregnated with flame retardants and antiseptics.

2. On the walls, at the same level, in accordance with the calculated step of the beams, fix the supports (corners, clamps, brackets). Fastening is carried out with self-tapping screws or screws, screwing them into the holes of the supports.

3. Beams are laid on supports and fixed with self-tapping screws.

Stage #2. Attachment of cranial bars (if necessary)

If it is more convenient to lay the “pie” of the floor structure from above, that is, from the side of the second floor, cranial bars with a section of 50x50 mm are stuffed along the edges of the beams on both sides. The bottom of the bars should be flush with the surface of the beams. The cranial bars are necessary in order to lay the rolling boards on them, which are the rough basis for the ceiling.

You can do without cranial bars if you hem the boards from the bottom, from the side of the first floor. In this case, they can be fastened directly to the beams using self-tapping screws (nails are not suitable, as they are difficult to drive vertically into the ceiling).

Stage #3. Fastening boards for the rough base of the ceiling

When mounting from the side of the second floor, roll-up boards are fixed to the cranial bars with nails or self-tapping screws (it is possible to use OSB, plywood).

When fastening the roll from the side of the first floor, the boards are fixed on the beams from below with the help of self-tapping screws. If necessary, lay a thick layer of insulation or soundproof material between the beams; the option of filing boards from below is preferable. The fact is that the cranial bars "eat up" part of the inter-beam space, and without their use, the thickness of the ceiling can be completely laid with insulating material.

Stage #4. Vapor barrier installation (if necessary)

The vapor barrier is laid in the floor structure in front of the insulation (which can also act as a sound insulator), if there is a risk of steam entering it or condensation. This happens if the overlap is arranged between floors, the first of which is heated, and the second is not. For example, an unheated attic or attic is being built above the first residential floor. Also, steam can penetrate into the floor insulation from damp rooms on the ground floor, for example, from the kitchen, bathroom, pool, etc.

The vapor barrier film is laid on top of the floor beams. The canvases are overlapped, leading the edges of the previous canvas to the next by 10 cm. The joints are glued with construction tape.

Stage #5. Thermal or sound insulation device

Between the beams, slab or roll heat or sound insulators are laid on top. Cracks and voids must be avoided, materials must fit snugly against the beams. For the same reason, it is undesirable to use trimmings that have to be joined together.

To reduce the occurrence of impact noise in the ceiling (with a residential upper floor), sound insulator strips with a minimum thickness of 5.5 mm are laid on the upper surface of the beams.

Stage #6. Laying waterproofing film

A waterproofing film is laid on top of the heat or sound insulating layer. It serves to prevent the penetration of moisture from the upper floor into the insulating material. If the upper floor is non-residential, that is, no one will wash the floors there and the penetration of atmospheric moisture will also be excluded, the waterproofing film can not be used.

The waterproofing film is laid in sheets, overlapping by 10 cm. The joints are glued with adhesive tape to prevent moisture from penetrating into the structure.

Stage #7. Fixing boards (plywood, OSB) for the subfloor

A draft base for the floor of the second floor is sewn along the beams from above. You can use ordinary boards, OSB or thick plywood. Fastening is carried out using self-tapping screws or nails.

Stage #8. Sheathing of the ceiling from below and from above with finishing coatings

On top of the draft base from the bottom and top of the floor, you can lay any suitable materials. On the upper side of the ceiling, that is, on the floor of the second floor, coatings of laminate, parquet, carpet, linoleum, etc. are arranged. When arranging the floor non-residential attic, draft boards can be left without sheathing.

On the lower surface of the ceiling, which serves as the ceiling for the first floor, ceiling materials are sewn: wooden lining, plastic panels, drywall constructions, etc.

Operation of floors

If beams with a large margin of safety were used in the structure, laid with a small step, then such an overlap will not need to be repaired for a long time. But still, you need to check the beams for strength regularly!

If the beams are damaged by insects or as a result of waterlogging, they are strengthened. To do this, the weakened beam is removed, replaced with a new one, or reinforced with durable boards.

All photos from the article

There is a growing number of new wooden houses everywhere, but along with these buildings there are many old buildings, also built using lumber. And of course, many owners of old cottages and dachas sooner or later wonder how to replace a beam in a wooden house.

Bearing beams are bars with a rectangular, less often round section. To ensure long-term operation, these structural elements are treated with deep penetration impregnations of strengthening and disinfecting action.

Beams are used for floor construction, where they are used as a log, for the construction of interfloor ceilings and for the manufacture of a truss system.

The choice of wood for use in construction is not accidental, since the price of lumber is still more affordable than the cost of metal structures with less weight and comparable strength. But, along with many obvious benefits, lumber is characterized by a number of disadvantages, due to which the logs lose their original performance over time and need to be repaired.

In this article, we will consider the main characteristics of beams and the features of their application. In addition, we will talk about the requirements for wooden floors and how to correctly calculate the parameters of the beams in order to meet these requirements.

Requirements for wooden floors

The materials used for the construction of floors should be characterized by a number of qualities, among which we note the following:

Resistance to mechanical stress, since the floors must be strong and at the same time withstand both variable and constant loads without deforming.
Rigidity and, as a result, resistance to bending. This quality is especially relevant for lumber used for flooring.
Resistant to humidity and temperature extremes. This is important property, which determines the durability of the operation of the floor. If the beams do not differ in these qualities, then most likely they will begin to rot after a while, which will accelerate their destruction.
Resistance to biological factors. If the lumber is resistant to the invasion of the bark beetle and other microorganisms, the floor structure will not need to be repaired for a long time.

So, we found out what requirements are imposed on the selection of material for the manufacture of elements in the floor structure. It remains to decide which wood is suitable for these purposes.

In the production of load-bearing beams, it is customary to use softwood. This material has a higher bending strength compared to lumber made from hardwood.

With technical specifications wood you can find in the following table.

Regardless of what kind of lumber the floor is made of, the carrier beam must be dry and dense. These qualities are easy to check - hit the workpiece with the butt of an ax and listen, if the sound is sonorous, then this is what we need, if the sound is deaf, then the lumber still needs to be dried.

Important: At the stage of logging, pay attention to the presence of damage caused by the bark beetle.
As a rule, these are small (up to 2 mm in diameter) holes located in small clusters.
If there are such wood defects, the purchase of these lumber should be discarded, since it will be very difficult to remove the beetle.

Classification

Bearing beams, according to the configuration, are divided into the following categories:

Massive modifications are made from an array of hardwoods, mainly coniferous, less often deciduous trees.

How to align floor beams with metal corners or a strip? How to level floor beams

How to strengthen wooden floor beams

Ecology of consumption. Homestead: Damaged wooden beams, worn out by loads and time, or not strong enough initially "by design" - this is the first reason for weakening bearing capacity ceilings, the appearance of vibrations and creaks of floors on the upper floors of the house. Let's figure out how to strengthen wooden beams and make them stronger structural elements overlap.

Damaged wooden beams, worn out by loads and time, or not initially strong enough “according to the project” - this is the first reason for the weakening of the bearing capacity of floors, the appearance of vibrations and creaks of floors on the upper floors of the house. Let's figure out how to strengthen the wooden beams and make the structural elements of the floor stronger.

Reasons for weakening beams

The need to strengthen beams may arise in a number of cases:

natural wear and tear of a properly installed product;
beam damage due to manufacturing and installation errors;
change in the purpose of the premises, associated with an increase in the load on the floors.

Let's consider these reasons in more detail. So, the beam can come into an unsatisfactory state due to the influence of various factors, including advanced level humidity, sudden temperature changes, as a result of the vital activity of pests, as well as simple physical wear and tear with the further appearance of cracks.

The dishonesty or incompetence of the builders should not be discounted. The owner of the house is not able to check the quality and correct installation of the elements flush-mounted. Problems are revealed later - already during the operation of the premises, when walking on the top floor, the floors vibrate or creak.

The main errors at the stage of manufacturing and installation of beams include the following:

use of insufficiently or incorrectly dried wood. After drying of such beams, they become covered with cracks;
using too thin a beam, which leads to vibration of the beams;
too large spans between beams;
assembly of beams from several parts.

If we are talking about changing the purpose of the room - for example, the attic is planned to be turned into an attic or a residential block, then in this case the load on the floor will increase. Obviously, this will require an increase in the bearing capacity of the beams.

A non-specialist can determine the need to strengthen the beams. The main indicator in this case, in addition to the mentioned vibrations or visible damage, is the level of deflection that occurs both under load and under the own weight of the beam. The deflection may increase after increasing the load - the installation of parquet on the top floor or after the delivery of furniture. In this case, the beams begin to sag, which is not only fraught with vibration of the floors, but can also threaten their collapse.

The maximum allowable beam deflection is easy to calculate on your own. The simplest technique is to calculate the index depending on the length of the beam. In particular, the level of deflection should not exceed approximately one three hundredth of the length of the product. For example, if the deflection is 8–10 millimeters with a beam length of 2.5 meters, this is the norm. If it turned out to be large, then it means that it is time to strengthen or replace the beam.

Increasing the cross-sectional area of the beam

One of the most popular ways to strengthen floor beams is to increase their cross section by installing additional wooden overlays. Basically, this method is used in cases where the material of the beams becomes loose due to natural aging or as a result of the vital activity of wood-boring beetles.

An increase in the cross-sectional area is achieved by installing overlays made of wood with a thickness of at least 50 mm on a weakened or damaged area. Some experts argue that it makes sense only to increase the cross section along the horizontal sides, that is, from above and below the beam, and increasing the thickness of the product in width does not give a useful effect.

Before installing the overlays, as in the case of other work to strengthen the beams, the weakened areas should be treated with antifungal agents. After antifungal treatment, the level of deflection should be minimized with the help of jacks. It is more efficient to directly install the overlays along the entire length of the beam. Attachment is carried out using bolts or studs through and through.

As a reinforcing element, you can use not only wood, but also metal. In this case, channels or metal strips are used. The latter are less reliable than the channel, and can only be used to reinforce small sections of damaged beams.

The reinforcement of the beam span with the help of metal overlays is carried out according to the same algorithm as in the case of wooden overlays, however, it has some peculiarities. In particular, before installation, metal linings are treated with an anti-corrosion compound. In addition, a waterproofing layer should be arranged between the metal and wooden parts.

Bar prostheses

In cases of severe damage to sections of the beams, it is practiced to remove such zones and install bar prostheses made of steel reinforcement. This method is used mostly when replacing the end elements, which become unusable most often.

In the role of prostheses are cuttings of reinforcement with a cross section of 10 to 25 mm. The length of the prosthesis is chosen with the expectation that it should be 10% longer than the double length of the damaged section of the beam. There is also a limitation on the length of the prosthesis - it can be no more than 1.2 m.

Before performing work, it is necessary to support the area to be strengthened with a stand to prevent possible collapse of the structure. Racks and support run are placed at a distance of one to one and a half meters from the bearing wall. After such a temporary strengthening, the ceiling is disassembled, and the rotten section of the beam is sawn off.

The prosthesis blank is inserted vertically into the overlap and then rotated to a horizontal position. The structure is first pushed onto the beam and then into the niche of the wall. It should be taken into account that beams restored with the use of prostheses will last for a long time, however, the strength of the updated structure will certainly be lower than in the case of a new beam. Therefore, the load of the restored beams should be kept to a minimum.

Reinforcement of beams with carbon fiber

In addition to traditional technologies, when strengthening beams, innovative solutions are widely used, one of which is the reinforcement of structures with carbon fiber. Attention: this method is the only possible way to strengthen the beams if, due to the extreme crampedness of the premises or for some other reason, it is impossible or extremely difficult to increase the section of the structures.

The undoubted advantage of carbon fiber reinforcing elements is the absence of the need to operate with overall and heavy metal or wood components, as well as the minimum labor intensity of work in general. Modern carbon plastics, like any composite materials, are characterized by high strength and low weight. Carbon fiber reinforcing elements perfectly cope with significant mechanical loads. They are produced in various modifications - in the form of tapes, fabrics, threads, plates or sheets.

Reinforcement of the beam with composites is carried out by gluing carbon fiber onto it in several layers. Attached layers of CFRP are applied to the surface of the beam one above the other and along its entire length. The edges of the glued strips must be covered with transverse layers. The reinforcing components are glued on until the reinforced beam is stiff enough to withstand the loads. Installation is carried out using epoxy glue. After hardening, the layer in terms of strength characteristics is sometimes not inferior to metal.

What to do if it is impossible to strengthen the beams

If the floor beams are not damaged, but they can hardly withstand the load and bend, and their strengthening is problematic or impractical, you need to consider the option of arranging additional beams or placing supports under the existing ones. In this case, the bearing capacity of the structures will be enhanced by redistributing the load on additional beams or racks. The latter, of course, will transfer the load to the floors of the lower room.

New understudy beams, just like the existing ones, are fixed in a nest arranged in a load-bearing wall. Installation of racks - albeit more simple task, however, it is often associated with an additional undesirable effect - such supports can clutter up the space and interfere with unhindered passage through the room. The visual component is also important - it is desirable to decorate the supports so that they harmoniously fit into the design of the room.

So, we examined several basic, most common ways to strengthen beams. Choice specific method depends both on the degree of wear of structures and the load on them, and on the skills of the builder, the availability of the necessary tools, financial capabilities and free time of the master. published by econet.ru

If you have any questions on this topic, ask them to specialists and readers of our project here.

P.S. And remember, just by changing your consumption, we are changing the world together! © econet

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Answers to frequently asked questions

Sometimes, as a result of the fact that the wrong section of a wooden beam was chosen, its deflection occurs. This can happen when there was some kind of internal defect in it in this place, which reduces its strength, or a supporting roof element (riser, stop, brace) was installed on it, the installation of which was also not taken into account when choosing a section. What can be done in this case? Especially when the roof has already been built and it is not possible to replace the beam with another.

As an option, you can align the floor beams with metal corners or a strip. To do this, it is necessary to install a jack under the problematic beam and raise it at the deflection point so that it is slightly higher than the horizontal level (1-2 cm). For control, you can stretch the cord horizontally nearby and focus on it.

After the place of deflection is raised, metal corners 75x75-50 mm or steel strips 5x75 mm are fixed along its sides, in which holes for Ø 12 mm bolts are pre-drilled. With a slight deflection of the ceiling, they can be fixed horizontally on both sides with bolts of the appropriate length. If the deflection is significant, you can fix them diagonally, with a rise to the middle of the beam.

After the metal corners or strips are securely fastened with bolts, the jack can be removed.

Fig.1 Alignment of a wooden beam: 1 - beam; 2- metal corner or stripe; 3 - bolt; 4 - jack; 5 - horizontal level (cord).

In addition, if a non-residential attic space is located above the bent beam, it can also be leveled with the help of an additional beam. It can be laid perpendicular to the one that requires alignment, or along and next to it. In both cases, the place of deflection is also lifted with a jack, after which the beams are fastened together with clamps or using the same corners or strip and bolted connections. After that, the jack is removed.

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Answers to frequently asked questions

After the metal corners or strips are securely fastened with bolts, the jack can be removed.

Fig.1 Alignment of a wooden beam: 1 - beam; 2 - metal corner or strip; 3 - bolt; 4 - jack; 5 - horizontal level (cord).

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: Wooden house:: BlogStroiki

Question: During the construction of a house from a bar, the workers brought the floorboards to the second floor, Folded them in the middle of the room, the width of which was 4 meters. The boards lay through the winter. Now we have seen that the floor beams of the second floor are bent, the deflection is significant. They wanted to put jacks-compensators for the shrinkage of the timber. Raise the beams from below and leave for some time. Will it help? We don’t know where to start. Please tell me how to do it right and how to install jacks, if there is a need for them? And for how long? And is it possible to solve this problem?

Answer: It is bad that you did not indicate which floor beams you laid and in what step, in order to find out what maximum load your beams are designed for and draw the right conclusions about their reliability. And what kind of deflection do you consider “significant”? A span of 4 meters must withstand a total load of 400 kg. per m2, did the floorboards with their weight lead to the deflection of the beams? Perhaps there was some other active load? Okay, what happened happened. Looking for a way out of this situation.

Definitely, the beams need to be raised and their bearing capacity strengthened. You can raise them with screw construction jacks or simply with vertical bars, slightly longer than the distance from the floor to the ceiling beam. A question about the floor - if the floor is wooden along the logs, then there is a problem with installing jacks - by raising the ceiling beams, you bend the floor logs. In this case, you need to look for a rail or an I-beam and lay it with its ends directly on the foundation, and only after that you can install jacks or retaining beams.

And now let's look at how you can align and strengthen the floor beams. With the help of a “sandwich”, we take metal strips with a width equal to the height of your beams and a thickness of 3-4 mm. For 4 meters of span, two meters are enough, and after raising the beam to the initial level, we apply strips on both sides of the beam, drill and tighten the “sandwich” with bolts. We install the bolts after 50 cm of the linear length of the plates. And so with the help of plates we strengthen in turn all the ceiling beams. Instead of metal strips, a bar of the same section as the beams, 2.5-3.0 meters long, can be attached to the beam with screws or studs.

The second way. We lay additionally four reinforced ceiling beams 15x15 cm or 15x20 cm, two of them are laid in the place of the greatest deflection (see Fig. 1.). Perpendicularly, according to the long size of the room, we lay the transverse beam, resting it on the load-bearing walls. With the help of tie bolts, we tighten the sagging beams to the transverse beam.

The same beam can be installed with inside rooms, beautifully decorating it, especially since you have a wooden house. Good luck.

Fig. 1 We strengthen the ceiling beams. 1. ceiling beam; 2. additional ceiling beam; 3. cross beam;

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Ceilings on wooden beams

When building a house, many people prefer instead of reinforced concrete interfloor ceilings to arrange floors on wooden beams or logs.

This is entirely justified. After all, wooden floors along the logs are much lighter than reinforced concrete ones, and with a low bearing capacity of the soil, it becomes possible to build less massive foundations.

Also important is the cost of a wooden interfloor ceiling. It is several times cheaper than reinforced concrete. The price of a tree is much lower, while there is no need to use cranes, and the floor beams can be laid on their own.

Many people ask themselves the question “How to calculate the floor beams?”, “What section should the beam have?”, “At what distance should they be installed?”

In this article, we will try to answer these questions, as well as talk about how a wooden floor is arranged along the beams, how they should be correctly fixed in the wall and give a table by which you can easily calculate the floor beams.

Let's start with the main bearing element - floor beams. As a rule, a beam is a wooden beam, from 100 mm to 300 mm high and 75-200 mm thick. It is laid in increments of 60 to 100 cm. The cross section of the beam is selected individually in each individual case and depends on the length of the span and possible loads. A table will be presented below for calculating wooden floor beams.

In addition to timber, for wooden floor beams, you can use boards knocked together, placed on edge. The most economical option would be to use logs hewn on three sides as beams.

Calculation of floor beams

In order to make a calculation of an interfloor or attic floor, it is necessary to determine the loads that act on the beams. It can be quite problematic to determine them, so they take averaged data. The total load will consist of the weight of the floor itself and the temporary loads i.e. loads from people, furniture, various equipment, etc.

On average, the total total load on wooden floors is taken equal to 400 kg / m2.

Below is a table by which you can determine the required cross-section of floor beams, depending on the length of the span and the installation step.

For example, with a span length of 5.5 m and an installation step of 0.6 m, a beam with a thickness of 150 mm and a height of 200 mm is required. In this case, it should be borne in mind that the length of the beam will be longer. it should go into the wall by 15 cm. Thus, the length will be 5.5m + 0.15m + 0.15m = 5.8m

Fastening floor beams to the wall

In the article "Interfloor floors" we talked about how reinforced concrete and wooden floors should be mounted in a wall of aerated concrete blocks.

In this part, we will consider the knot of support of a wooden beam on brick walls.

As we wrote above, the length of the support of the beam on the walls should be at least 15 cm.

Before laying the beam, it must be cut from the end at an angle of 600, treat the entire beam with an antiseptic and wrap the ends in two layers of roofing material to prevent decay.

After that, a roofing material is laid on the wall, on which a lining board is laid. It serves to distribute point loads from beams to the entire surface of the wall.

A floor beam is placed on the lining, an anchor from a steel strip is nailed to it, which is subsequently embedded in brickwork.

When installing wooden beams, you must leave a temperature gap of at least 3 cm to compensate for the linear expansion of wood.

If the beams are supported by an internal load-bearing wall, then the design is similar to the previous one, with the only difference being that the floor beams are connected to each other with a metal tape. More clearly, the whole scheme can be seen in the figure.

Laying wooden beams begins with the most extreme. First they are leveled, and then the rest are placed on them. To align the remaining beams in height, cut boards are placed under their ends.

Floor installation on wooden beams

After laying the beams, you can proceed to the flooring. Exist various designs interfloor floors. All of them are built on the same principle.

We give only a general device for the attic and the floor of the first floor. There is no need to insulate the ceilings between the first and second floors, because the temperature on these floors is approximately the same.

The attic floor is made according to the following scheme: a vapor barrier is sewn onto the floor beams from below, after which boards, lining, OSB boards or other coverage. Next, the insulation of the desired thickness is laid.

In the article “Roof Insulation”, we considered how to independently calculate the required thickness of insulation for the roof. For the attic floor, the calculation is carried out in the same way.

The insulation on the first floor is slightly different. In this case, the vapor barrier film is located on top, and the waterproofing is on the bottom. For more information about the device of a wooden floor on logs, read the article "Device of a wooden floor"

At the end of the article, we suggest you watch a video from which you will learn how in a simple way make soundproofing of the interfloor ceiling on wooden beams.

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One of the main ways that you can use to make a flat floor surface is to lay a board or sheet materials on a previously created crate, where lags are used as load-bearing elements. One of the primary tasks, the implementation of which directly affects the final quality of the floor surface, is the alignment of the log in the horizontal plane, their reliable fixation, as well as the treatment with protective compounds and waterproofing. How to adjust the position wooden beams, as well as some of the nuances of the process of mounting the frame under the flooring of the horizontal floor surface, you can find out by reading this article. The thematic video lessons offered for viewing will help to consolidate the information received.

Features of the floor by lags

There was a period when developers began to move away from the technology of laying the floor base on wooden blocks. This was due to the fact that in this way it was difficult to achieve perfect flat surface, which was necessary for laying modern flooring. The advantage was given to screeds made with cement-based mortars.

Right now modern technologies lumber production allows to produce wood products that are distinguished by regular geometric shapes, and special impregnations make wooden beams durable and prevent their deformation. There are also more advanced materials at a reasonable price for decking, such as plywood and OSB boards. This made it possible to return to the technology of laying floors by joists, bringing it to a higher quality level.

The massive use of this method of arranging a floor surface is also explained by the popularization wooden construction when houses are built from logs or timber. In such a building, any floors other than wood would look inorganic. However, logs as a frame for flooring are used not only in wooden houses. This floor leveling technology is used everywhere. In private houses, including those on the second floor, in city apartments and even in office space. To explain the popularity of this technology will help its advantages, such as:

relatively small price complex material / work, especially when it comes to the device of overlapping on the second floor of the house;
the ability to qualitatively insulate the floor surface by laying a thick layer of insulation;
the created surface is immediately ready for the installation of finishing materials (does not need drying and maturation, like concrete);
it is convenient to lay communications under the flooring;
the frame made with bars, as well as the flooring, have a relatively light weight, due to which the load on floors and load-bearing structures is noticeably reduced;
the workflow is quite simple, making it accessible to many home craftsmen.

This floor also has some disadvantages:

despite the use of flame retardants, wood remains a combustible material;
the use of logs, for example, in an apartment, provides for a decrease in usable volume;
the impossibility of making the floor heated.

Base surfaces for installing logs

A horizontal frame of wooden beams can be made in any room. But the base surface, which serves as a support for the lag, is different. If the floor structure is assembled on the ground floor of a private house with a ventilated underground, there are columns poured with concrete or bricked as supporting elements. In apartments, and some houses on the second floor, where it is flooded as an interfloor partition reinforced concrete slab, the latter is the basis for the installation of load-bearing bars. When a floor is made on the ground on the ground floor of the house, a rough screed is prepared for the installation of the bars. Let's look at the installation rules and how to align the load-bearing bars in each of the options.

Important! If the interfloor ceiling in the house is made with timber, its surface is the basis for plywood, OSB or board flooring on the second floor. Alignment of beams occurs even at the stage of building construction.

How to align the bearing bars on a reinforced concrete slab?

You can install logs on the stove using several devices, such as:

screw adjustable supports;
support brackets;
anchor fasteners.

Screw supports and metal brackets are used when it is necessary to raise the floor surface relative to the base surface in order to lay insulation between the lags. With the help of these devices it is convenient to fasten the bars and adjust their position relative to the horizontal. Another plus of such devices is the absence of contact between wooden beams and a concrete surface, which eliminates the need for waterproofing the lag.

Anchors are used when the beam is laid directly on the concrete surface, and its position is regulated by all kinds of linings. This is done when the thickness of the thermal insulation layer does not matter much, at the same time there is a desire to minimize the usable space.

To align the logs and install them in the same plane, you need to use the hydraulic level and a long (1.5-2 m) spirit level. Using the water level, marks are made on two opposite walls, which correspond to the horizontal in which the load-bearing bars should be located.

The first to be installed and aligned are the extreme logs, which are located about 10 cm from the wall. First, one edge of the beam is set according to the mark that determines the desired horizontal level. Then the position of the other edge is adjusted so that the floor support is horizontal. The same should be done with a bar on the other wall.

When the extreme logs are set and fixed in a predetermined position, strong strings are stretched between them so that their sagging is minimal. Stretched threads located in the same horizontal plane will be a guideline for adjusting the position of the intermediate lags. To mark the horizontal, if possible, you can use a laser level. This will speed up the process and possibly improve accuracy somewhat. You can see how the lag is installed on metal brackets, as well as their alignment, in the video below, which shows the entire process of installing a plywood floor base along the load-bearing beams on the loggia.

Logs on columnar supports

In this case, in order to avoid problems with aligning the lag, the supports themselves should be made for them so that they upper platforms were in the same plane. The principle is the same - a horizontal line is marked in which the upper points of the columns will be located and the threads are pulled. If the supports are made of reinforced concrete, formwork elements are placed along the threads. When the columns are laid out of brick, the masonry is adjusted according to the guidelines.

The bars are installed on the supports made after laying 2-3 layers of a rolled waterproofing agent on them and fixed with metal squares or anchors through the lag body to the surface of the column. The load-bearing wooden crossbars are leveled by laying wooden or plastic wedges.

Important! It is necessary to lay a waterproofing material not only between the surface of the column and the log, but also between the support and the ground so that moisture does not destroy the supporting structure.