The device of a floor on wooden beams of overlapping. How to make interfloor wooden floors in brick and wood houses. Stage #1. Installation of floor beams

Today, residential buildings made of wood are the most popular. At the very beginning of construction, each developer faces the task of what the floors in a wooden house should be like. After all, they are necessary to ensure the strength of the roof, the uniform distribution of the interfloor load, the stability of the walls of the entire low-rise building. This is the main purpose of overlapping structures.

In addition, their device largely provides effective insulation of the entire dwelling and, first of all, the ceiling.

In the construction business, the following overlaps are known:

Mounted between the living room and the attic. They must perform functions such as vapor barrier and insulation. For interfloor partitions, these qualities are not so important, for them the most significant factor is sound insulation. Basements are often not heated. Therefore, their overlapping devices must be made not only with increased strength, but also with high resistance to damp cold air. If the basement is built for a garage, then soundproofing will not interfere with its ceiling.

The most important components of the beam ceiling:

Primary requirements

The device of the bearing part according to the constructive solution can be beam or without the use of beams - monolithic. Beamless ceilings in a wooden private house are practically not used. Their advantage: high strength, resistance to moisture. For the entire period of operation, repairs may not even be needed. But soundproofing in such a dwelling is not at a high level. Already the appearance of a monolith dismisses the desire to make overlapping structures with your own hands. And the factory produces panels of standard sizes, which may not fit a specific span.

The developer usually does not hesitate to choose between a wooden beam and a monolithic floor. Concrete structures are unpopular not only because the house will not be provided with good interfloor sound insulation. In a few years, for old walls, they will be an excessive burden.

Detailed scheme of soundproofing wooden floors

Installation of metal and concrete structures, as well as their repair, is impossible with your own hands. Here one cannot do without the use of machines and mechanisms, as well as without the involvement of specialists who manage these means. And all this will be reflected in the higher cost of building the entire house.

Beams are wooden, metal, concrete. But regardless of the material of manufacture, the same requirements are imposed on all of them:

be strong, rigid, not bend between floors, withstand a uniform load in accordance with SP 20.1333 - Code of Practice of 2011 - not less than 200 kg per square meter;
provide insulation, laying materials on which interfloor sound insulation depends;
keep the layer of coating necessary to keep the heat on the floors;
their installation with their own hands should be as reliable as possible.

Ways of fastening beams

So that the floor is not unsteady, the beams are not laid pointwise, but in grooves about 70 mm deep, cut into the walls.

Mounting option for floor beams

The number of bearing bars should be sufficient to ensure the strength of the entire interfloor structure. Between the recess and the end, you can put an insulating material that will eliminate the appearance of a squeak.

The beams of the upper floor can be attached to the wall using the so-called dovetail method. To do this, at their ends it is required to make a double-sided diagonal hem, which is inserted into a socket of the same shape. True, this reduces the cross section of the logs, and longitudinal cracks may also occur in the sawing zone. The rigidity of the support decreases, the service life of the ceiling is reduced, which means that repair is approaching.

Wooden

Among future homeowners, wooden beam-based flooring is popular. It allows you to equip a fairly good home insulation. It has both advantages and disadvantages.

Scheme of the device of wooden floors for the house

Positive factors:

pleasant appearance;
relatively small weight;
quick installation and subsequent repair;
ecological purity.

it is flammable, special impregnation is required;
from temperature changes, humidity can be deformed;
the tree is subject to rotting, insects, fungi.

However, these shortcomings can be minimized, the repair can be postponed by using special fire-fighting solutions and antiseptics. To meet fire safety requirements, wooden parts are isolated from the chimney using asbestos. Between it and the nearest beam, a box is usually placed filled with non-combustible material, such as mineral wool.

Beam slats made of hardwood or softwood are more suitable.

Option for flooring in a log house

For the construction of residential premises, it is an environmentally friendly and relatively inexpensive building material. In addition, good sound insulation will be provided. Wood is easy to process and relatively inexpensive.

Installation of wooden floors on floors is possible in a short time and with your own hands, without the involvement of specialists and the use of lifting equipment.

Or do you need a more durable cover. If the beams are made of wood, then the distance between them must be made somewhat smaller. In this case, it is better if they are metal, and lay the wooden floor of the entire first floor on them. They are less susceptible to the adverse effects of the basement environment, so repairs will not be needed soon. When arranging a garage space, one should not forget about such factors as sound insulation and sufficiently effective insulation of the upper room.

Whole and glued

If the spans are not more than 5 m, then solid wooden beams are used, which are quite capable of ensuring the strength of the ceiling and equipping a reliable floor. But they can be glued, for which there are no restrictions on the length. They are superior to non-glued in the following parameters:

high strength;
long service life;
lack of deformation;
the ability to carry out the installation of ceilings in long spans.

In interfloor ceilings, they are often left open from the side of the ceiling. Their smooth surface with an attractive natural wood pattern enhances the design. It is also not closed by floors, as it gives a special appeal to the room. In the appropriate style, you need to arrange the floor.

It should be made of wooden boards, in color in harmony with the design of the entire room.

I-beams

I-beam structures are widely used. Often they are chosen by the user who cares about the insulation of his house and interfloor soundproofing. I-beams are easy to make from ordinary glued beams. In shape, they resemble two letters "T", connected at the base. They replace the mass of load-bearing beam rails, reduce the time spent on laying floors, and, importantly, they can be used for installation in spans up to 15 m.

I-beams are not deformed from exposure to moisture, they will not need frequent repairs. With their use in a house with their own hands, excellent interfloor sound insulation and fairly effective insulation can be equipped. To eliminate the possibility of floor creaking, the so-called subfloor is nailed to them.

An example of I-beams in a wooden house

Their design is very convenient for laying communications on floors: electrical wiring, water and gas pipes, ventilation.

Boards instead of beams

In construction practice, a floor device is used, in which thick boards placed on the edge are used instead of load-bearing beams. It is preferable that they have a cross section of at least 60x200 mm. Their ends are cut into the full thickness of the wooden wall. They are strengthened one from the other at a distance two times less than the distance between the beams of glued laminated timber or logs. Installation of this design is possible with narrow spans. Then the floor will be very stable, and the arrangement of the ceiling will require conventional materials to provide insulation and create good sound insulation.

Example of installation of floor boards

Wooden floors between floors are usually used in low-rise private construction of houses made of wood, brick or foam blocks. Wooden floors have a number of advantages: they do not make the structure heavier, they allow you to do without the involvement of heavy equipment, they have sufficient strength and reasonable price.

The choice of material for wooden floors

Wooden floors are arranged with a span of no more than 8 meters. As the main load-bearing structures, beams made of timber with a cross section of 50x150 to 140x240 mm or debarked logs of the appropriate diameter are used. The pitch of the beams is determined by calculation and usually ranges from 0.6 to 1 meter. For the manufacture of beams, only coniferous woods are taken - their bending strength is much higher than that of hardwoods. Logs or beams for beams must be thoroughly air-dried under a canopy. When tapped with the butt of an ax, the beams should make a sonorous clear sound. The length of the floor beams must be such as to firmly rest in the nests of brickwork or log cabins.

In addition to beams, for the implementation of interfloor ceilings, they use:

Cranial bars with a size of 50x50 mm - they are attached to the bottom of the beams on both sides and the ceiling of the lower floor is hemmed to them;
Board of the subfloor of the upper floor. For these purposes, you can take any board, including unplaned;
Floor boards of the upper floor - planed tongue-and-groove board;
Insulation. As a heater in wooden floors, it is better to use mineral slabs or rolled material, since fibrous thermal insulation, unlike polystyrene, does not support combustion and has good soundproofing properties;
Hydro vapor barrier film designed to protect the insulation from moisture vapor;
Antiseptic for wood and bituminous mastic, scraps of roofing material;
Decorative floor and ceiling covering.

Structure - what is a wooden floor made of

Technology for the implementation of wooden floors between floors

Beams of interfloor ceilings are usually laid in the walls during the construction of the house, and all other work on the construction of floors is carried out after construction before the start of finishing work. Before performing the floors, it is necessary to calculate the load on the floors, based on the data obtained, the dimensions of the beams and the laying step are selected.

Floor beams are brought into a brick or block wall during masonry; for this, special nests are made in the wall. The depth of the nest must be at least half the thickness of the wall; you can make it through, followed by sealing with a vapor-permeable insulation.
In wooden buildings, beams are cut into the upper crown of the log house. Beams must be pre-treated with an antiseptic and dried. Rectangular beams are laid so that the wide side is vertical - with this laying, their rigidity increases. The ends of the beams are cut at an angle of 60 °, treated with bituminous mastic and wrapped with roofing material in two or three layers. First, the extreme beams are laid in place. They are leveled with a long board placed on the edge and a level, if necessary, the beams are leveled with linings from boards of different thicknesses, pre-treated with bituminous mastic and placed in a nest. The intermediate beams are aligned with the board laid on the extreme beams.
After the walls and the temporary or permanent roof are completed, the construction of the ceilings begins. Cranial bars are sutured to the bottom of the beams on both sides. Their purpose is to support the subfloor of the upper floor and the filing of the ceiling for the lower one. For cranial bars, a 50 mm pine bar treated with an antiseptic is required. It is attached to the floor beams with wood screws. Subfloor boards are laid on the cranial bars. For them, you can use an unplaned board with a thickness of 15 mm or more - the load on the subfloor is small, so it is not necessary to spend money on a thick board. The boards of the subfloor are laid perpendicular to the beams, resting them on the cranial bars, and fastened with self-tapping screws. The draft floor is also treated with an antiseptic.
A hydro-vapor barrier film is laid on top of the subfloor and floor beams, for example,. The strips of the film are overlapped, gluing the joints with adhesive tape. Mineral insulation is laid on top of the vapor barrier film in the form of plates or rolls. The thickness of the insulation must be such that it does not protrude above the surface of the beams. Other materials can also be used as insulation: expanded polystyrene, expanded clay, ecowool. In this case, it is necessary to pay attention to the fire resistance of the insulation material.
On top of the floor beams lay the logs of the floor of the upper floor. The direction of laying the log is across the beams, the step is from 60 cm to 1 meter. Logs are made of a bar or board with a thickness of at least 40 mm and are attached to the floor beams using metal corners fixed to self-tapping screws. Between the lags, you can lay another layer of mineral insulation, blocking the joints of the lower heat-insulating layer. Mineral insulation will also serve as soundproofing of the floor and ceiling. A waterproofing film is laid on top of the second layer of insulation in case of a liquid spill.
The floor of the upper floor along the logs is sewn up with a finishing floorboard, drywall or plywood, on which any finish coating can be laid: tiles, laminate, linoleum or cork. The floorboard or plywood is fixed on self-tapping screws. Can be arranged under the finish coat, while it is better to use a foil film as a vapor barrier.

Wooden floors between floors, unlike concrete slabs, do not create an unnecessary load on the foundation, therefore, it is possible to significantly reduce the cost of building a powerful foundation. Properly executed ceiling is quite strong and durable, has good heat and sound insulation properties, in addition, natural materials allow ceilings to "breathe".

Private low-rise construction has become increasingly popular in recent years.

Do-it-yourself country houses and summer cottages occupy an increasing share in the total volume of housing being put into operation.

The most demanded material in private construction is wood, due to its affordable cost and ease of processing. But not all individual developers have sufficient experience and knowledge to independently carry out the entire range of construction work. So, the question often arises of how to properly lay the floor of the second floor in compliance with all building codes and technologies.

Construction requirements for wooden floors

In order to mount a durable and safe wooden floor between the 1st and 2nd floors with your own hands, you must strictly comply with the technical requirements for them.

Thermal insulation layer

Thermal insulation of the floor will improve the temperature in the room on the second floor

If the wooden floor will separate the upper and lower rooms with a temperature difference between them of more than 10 ° C, it will be necessary to build a heat-insulating layer.

This is necessary, for example, when arranging ceilings between the first floor and the underground, basement or between the first / second floor and an uninsulated attic.

Beam strength

Beams and ceilings must withstand up to 180 kg / sq.m of load

When constructing the floor of the second floor on wooden beams, special attention should be paid to the strength of the supporting structures. The safety of the operation of the building depends on how durable the wooden beams of the floors are.

According to building codes for wooden low-rise buildings, the maximum load on the floors of the first floor should not exceed 210 kg per sq.m., the pressure on the wooden floor of the second floor should not exceed 180 kg / sq.m., and for attics and attics this figure should be less than 105 kg/sq.m.

Maximum deflection

In addition, building codes also impose requirements on the deflection of wooden floor beams. According to SNiP, this coefficient should not exceed 1 to 250. That is, the maximum deflection of wooden supporting structures during operation should be less than 4 mm per meter of beam length.

According to this standard, the deflection of a beam structure 4 m long in the center should not be more than 1.6 cm (4 m: 250 = 0.016 m). If it is planned to place massive furniture and household appliances in the room, flooring as a floor covering of tiles, etc., then the requirements for structural rigidity increase to 1 to 400.

That is, the deflection should not exceed 2.5 mm per meter. For non-residential attics and attic spaces, a larger deflection coefficient is allowed - 1 to 200 (5 mm per 1 meter).

Soundproofing

Fifty-millimeter mineral wool will not only insulate the floor, but will also become a good sound insulator

According to building codes, the sound insulation threshold for interfloor floors of residential buildings should be 50 dB.

To ensure this requirement, it will be enough to cover the floor of the second floor under the finish coat with mineral wool 50 mm thick.

The length of the beam should be no more than 5 m

The maximum allowable length of the free sag of wooden beams should not exceed 5 m for interfloor and 6 m for attic floors. If the design length of the room is more than 5 m, it will be necessary to install an additional support under the bearing beam. The fact is that the optimal length of the supporting wooden structure is 4 m.

With a further increase in its length, the rigidity and strength of the supporting structure are sharply reduced and the requirements for the thickness of the beam section increase disproportionately. So, in order for the deflection indicators for an 8 m beam to “fit” into the SNiP standards, its thickness should be about 40 cm. For example: the same deflection indicator shows a 4 m beam with a cross section of only 15 x 15 cm.

Wood is a material quite vulnerable to external influences, primarily dampness and fire, therefore, before proceeding with the construction of load-bearing structures, all wooden elements must be treated with antiseptic materials and flame retardants.

Construction material

Before proceeding with the installation of the floor on the second floor on wooden beams, you should make a list of all the necessary materials. This will allow during work to avoid unforeseen downtime and delays caused by the need to purchase some building materials.

beams

A beam section of 15 x 15 will be enough

The basis of the entire structure of interfloor wooden floors is beams. They play the role of load-bearing elements, and the strength of the structure depends on them. For them, a bar or gun carriage with a section of 15 x 15 cm, or 18 x 18 cm is usually taken.

This section is usually enough to provide sufficient rigidity for a specific load of 400 kg per sq.m. In this case, it is necessary to observe the parameters recommended by building codes: the span is 4 m, and the step between the beams is 60 cm. Based on these parameters, you can also calculate the required amount of timber.

№	Span length (mm)	Beam cross section (mm)
1	2000	75×150
2	2500	100×150
3	3000	100×175
4	3500	125×175
5	4000	125×200
6	4500	150×200
7	5000	150×225

However, in the absence of a beam and small values of the expected loads on the floor, it is quite possible to use boards nailed together in pairs and placed on the edge with a thickness of 50 or 40 mm. This option is suitable for flooring in the attic or in a small country house.

For the first floor of a residential building, this option is not suitable due to the low bearing capacity of the boards: to ensure the necessary rigidity, the step between the plank beams will have to be significantly reduced, which will lead to unjustified waste of material.

The most commonly used material for beams is pine. This is the best option according to the "price-quality" criterion: its wood is quite affordable and at the same time has good technical characteristics.

Bars made of wood of stronger species (larch, oak) can rarely be found on free sale, and their price is incomparably higher, and pine wood after appropriate treatment with antiseptics will not be inferior in terms of durability to the same larch.

When buying a bar, you should choose a material with dry wood. Otherwise, after mounting the beams, their deformation during the drying process is possible - bending and twisting.

Flooring

Wooden decking laid on beams will be a rough base for flooring

Usually, the flooring of interfloor ceilings is made in two tiers: from below there are rough floors, on which insulation is laid, and from above - pre-finish flooring, mounted on top of the bearing beams. A decorative floor covering is laid directly on it.

To determine the nature and amount of material for flooring, you should clearly consider the design of the floors.

In the device of the subfloor, either 5 x 6 cm bars stuffed onto the supporting beams or grooves made in the beams can be used as a support for the floorboards. The latter option is quite laborious, so most often 5 x 6 cm bars are used to create a support.

To calculate the required number of bars, it is enough to count the number of beams and multiply them by the length of each of them. The resulting footage (the total length of all beams) is multiplied by two more (since the bars will be stuffed on both sides of each beam).

A wide range of materials can be used for finishing flooring. It can be boardwalk, plywood, chipboard, MDF, OSB, etc. Each of these materials has its advantages and disadvantages, after reading which you can choose one of them. To calculate the required amount of material, it is enough to simply calculate the area of \u200b\u200bthe room.

When purchasing building material, you should always purchase it with a margin of 10 - 15%, since unforeseen material overruns are inevitable during construction.

This will save you from having to interrupt work and buy the missing part.

Impregnation

Antiseptic will extend the life of the tree

To maximize the service life of wooden structures, they must be treated with antiseptic materials.

It will also be useful to treat wood with fire retardants, which increase its fire safety.

To calculate the required amount of impregnation, you should read the instructions for its use - it always indicates the approximate consumption of the mixture per sq.m.

Waterproofing

Since wood is afraid of moisture, waterproofing materials are always used in construction.

This can be rolled waterproofing used to create a water-repellent layer between wooden floor structures and the finish coat, or between wood and brick (stone, cinder block, etc.).

To protect the tree from moisture, you can also apply a coating waterproofing based on polymers or liquid bitumens.

Heat and sound insulation

If it is necessary to create a barrier to noise or cold, insulating materials are used in the construction of floors. Most often, for these purposes, use a minplate or foam. Their total number in area should be approximately equal to the area of \u200b\u200bthe room. For more information about floor insulation, see this video:

Expanded clay or ordinary slag mixed with sawdust can also be used as an insulating material.

Fastening materials

To fasten wooden floor elements, you should purchase self-tapping screws, nails, steel corners, anchor bolts and other consumables. When purchasing screws and nails, attention should be paid to their length.

According to the standards for a strong connection, the nail should be 2/3 longer than the thickness of the attached element (board, bar). For self-tapping screws and screws, this figure can be reduced to 50%.

Those. for reliable fastening to the beam of the “magpie” board, you will need 120 mm nails or 80 mm self-tapping screws.

After all the necessary materials have been purchased, and all preparations have been completed, you can proceed directly to the construction work. The construction of interfloor floors can be divided into several main stages.

The part of the beam inserted into the wall is wrapped with three layers of waterproofing material

The installation of load-bearing beams is most often carried out at the stage of erecting the walls of the building. Before laying the bearing bars, their surface is treated with all the necessary impregnations.

Then their ends are cut at an angle of 60 ° and that part of them that will be walled up in the wall is wrapped in 2-3 layers of rolled waterproofing.

The ends of the beams are usually also coated with waterproofing compounds, but some experts advise leaving them open to allow the moisture contained in the wood to freely escape.

The depth of the beams to the depth of the wall should be at least 15 cm. The step of laying the beams is usually taken at 0.6 m, but depending on the expected load on the floors, as well as on the thickness of the beam section, this indicator can be reduced or increased.

The choice of the interval between the beams is also influenced by the technical indicators of the material used for the finished floor.

If the top flooring is supposed to be made of inch boards, plywood or chipboard, then the distance between the beams should not exceed half a meter, otherwise the floors will sag when walking. For more information about the installation of beams, see this video:

Floor joists must lie in the same plane

The installation of load-bearing beams starts from the two extreme walls, while the beams should be located at a distance of 5 - 10 cm. After installing the two extreme beams, we mount the rest, observing the required interval.

When laying beams, special attention should be paid to the horizontal slope: all floor beams must lie in the same plane. To do this, a cutting board is placed on the edge between the two extreme bars, or the twine is pulled tightly.

If the base on which the beams are laid is uneven, then mortgages should be installed under the ends of the beams to level the horizontal level. For mortgages, material is used that is resistant to decay and physical stress - metal plates, pieces of tiles, etc.

It is not recommended to use wooden wedges to adjust the level of the beams, as they can quickly rot, which will cause the lowering of individual floor beams and the curvature of the floor line.

The bearing bars are attached to the wall with anchor bolts and steel corners.

Fastening of support bars

After all the floor beams are exposed, bars with a section of 5 x 6 cm are attached to them (the so-called "cranial" bars). They serve as a support for laying the subfloor and are attached along the entire length of the bearing beam, on both sides.

They should be nailed in such a way that their bottom is flush with the bottom of the beams.

Most often, the draft floor is made from an inch board.

For the device of the subfloor, edged boards are taken and laid across the beams on the support bars. Since the distance between the beams usually does not exceed 0.6 - 0.8 m, then an inch or thirty board is quite suitable for subfloors: the pressure on them will be limited only by the weight of the insulation.

Also for these purposes, you can use a cut slab. You can also combine the draft floors of the second floor with the finished ceilings of the first floor or basement. In this case, edged boards are hemmed from below, from the side of the first floor to the beams. For more information about the draft field, see this video:

Thermal insulation flooring

After the installation of subfloors, compartments are formed between the beams, which, if necessary, can be filled with heat-insulating materials.

To do this, a hydro- or vapor barrier (roofing material, isospan, etc.) is laid on top of the subfloor boards, and then mineral wool, polystyrene, slag with sawdust, etc. are laid.

In this case, the entire space between the bars should be densely filled. We fill the gaps between the beams and foam sheets with sealant.

It is also desirable to lay waterproofing on top of the insulation, which will protect it from moisture leaks from above.

The final stage will be the flooring of the finishing floors, which is mounted on top of the supporting beams with self-tapping screws or nails.

To do this, the material (boards, OSB, plywood) is cut in such a way that their joint falls in the middle of the timber. The finished floor is the basis for the finishing coating - laminate, linoleum, parquet.

In private low-rise construction, when constructing interfloor floors, massive reinforced concrete slabs are rarely used, preferring structures based on wooden beams. The advantage of such load-bearing structures is the relative simplicity of their construction, light weight and sufficient strength. Next, you will find out what material is needed to create the floor, and how the installation of the structure is carried out in practice.

The scheme of the interfloor partition - from the base to the finish

The basis of the floors constructed in private houses are based on. The following types of lumber can be used as them:

timber (massive, glued);
rounded (calibrated) log;
boards sewn together with nails, bolts or screws.

The lumber listed must be made from softwood, such as larch or pine. Spruce lumber is less durable due to the high content of branches, therefore it is used as beams of short length. Beams and hardwood logs are not used as the basis of floors, having low bending strength. The use of such a material will inevitably lead to deformation of the structure under the influence of a vertical load.

To create a continuous draft surface, the beams are sheathed on both sides with a board or slabs (OSB, plywood). From the side of the lower floor, the ceiling is further formed (plastic panels, drywall, wooden lining) on the second floor. The floors of the second floor on wooden beams can be laid directly on the slabs, boards that sheathe the load-bearing elements of the floors, or on additionally installed logs.

The beams are mounted with a certain step, which causes the presence of voids between the floor cladding. This feature is used for laying materials with soundproofing and heat-saving properties into the empty space. If wooden floors separate living quarters, their thermal insulation is not necessary - noise isolation is more relevant in this case. When the interfloor partition divides the heated space with a non-residential attic, the task of reliable insulation of the floor is in the foreground.

The most reliable soundproofing material is low density mineral wool. To create a heat-insulating barrier, polymeric heaters (polystyrene, extruded polystyrene, polyurethane foam) or the same basalt wool are often used. When using mineral (basalt) wool as a heater or soundproofing material, a vapor barrier is necessarily arranged from the side of the lower room and waterproofing from above.

We calculate beams - section, step, length

In order for the wooden floor between floors to be reliable, safe in operation and withstand the expected loads on its surface, it is necessary to correctly calculate what section of the beams is necessary and with what step they should be placed. It is clear that the thicker the beam or log, the greater the bending strength they have. The strength of the entire interfloor structure depends not only on the cross section of the beams, but also on the frequency of their location. The normal step of the bearing elements of the floors is the distance from 0.6 to 1 meter. It is unsafe to place beams less often, more often it is not rational.

The strength of a beam with the same cross section decreases in inverse proportion to the distance between its supports, that is, load-bearing walls, so the thickness of the main elements of wooden floors increases along with their required length. The normal distance between the supporting walls is 4 m or less. With a larger span, it is necessary to use non-standard beams with an increased cross section or reduce their step. Sometimes additional support structures (columns) are installed to reinforce the floors.

As beams, bars are mainly used, having a rectangular shape at the end, and the installation of the load-bearing elements is carried out so that the large side of the section is vertical. The normal sections of the bars are considered to be 16-24 cm on the vertical side in the cross section and 5-16 cm - horizontal. The boards fastened together also form a beam, but the strength of such a tandem is somewhat lower than that of a solid wooden part, which is taken into account when calculating the load on wooden floors. The most irrational type of lumber used as load-bearing beams is considered to be a log, which has approximately the same strength as a conditional beam, which could be obtained when processing round timber, but at the same time much more weight.

Accurate calculation of the allowable load on floor beams is the lot of professional civil engineers. To calculate the design strength of floors, very complex formulas are used, which people with special education can operate with. However, there are tables with which you can approximately select the cross section of wooden beams, depending on the distance between the supports and the step of the bearing elements of the floor. For example, with a span of 2 m between the supporting walls, a beam with a section of 75x100 at a step of 60 cm and 75x150 with a distance between beams of 100 cm is recommended. With the same distance between the supports, logs with a diameter of 13 cm (1 m step) and 11 cm (0.6 step) are needed m).

The indicated sections of load-bearing lumber are valid for an operational load on floors not exceeding 400 kg / m 2. Such a load is calculated in the case of a device on the second floor of a full-fledged living space. If the floors separate the lower rooms from the non-residential attic, they proceed from a load of 160 kg / m 2, at which the cross-section of the supporting beams is correspondingly reduced. If an increased concentrated load is expected in a certain section of the floor of the second floor (installation of massive objects), additional floor beams are installed in this place.

Methods for attaching load-bearing elements to walls - reliable fixation

The best way to install wooden floors between floors is to place beams in special niches that are formed during the construction of walls. Bearing logs or beams are inserted into the walls at least 12 cm on each side, which provides reliable support for the ceiling. This method is relevant when building walls from any building materials - in a brick house, in a building made of building blocks or made of wooden materials.

Niches for installing beams or logs are made larger than lumber sections. This is necessary for their correct installation in the sockets and the possibility of exposure in the same horizontal plane. Sections of the beams that are inserted into the walls are first treated with antiseptic impregnations, then coated with bituminous mastic, after which they are wrapped in rolled waterproofing material in two layers. The end part of the beam is cut at an angle and is not insulated. This is necessary to ensure the free exit of the steam formed when the wood is heated.

The processed and protected from moisture wooden beam is installed in a wall niche so that there is no direct contact with the building material used to build the walls. From below, a piece of wood treated with protective impregnations is placed under the log or beam, from the sides and from the side of the end, the gaps left for ventilation are filled with tow or glass wool. To increase the strength and reliability of the ceiling, every fourth or fifth beam is attracted to the bearing wall, using an anchor connection for this.

Inserting beams into wall niches is a classic method that has proven its reliability over many years of operation. But this method of fastening the load-bearing elements of interfloor ceilings can be applied only at the stage of building a house. To fix the beams to the built walls, special metal fasteners are now used, which are a kind of case for the end of the beam. Such parts are first attached to the walls, then load-bearing elements of the ceiling are inserted into them and fixed with bolts or self-tapping screws.

The second method of fastening wooden beams is considered more technological, the process of installing floors is faster. But if we take into account the reliability of the connection, the classic method, which involves supporting beams or logs directly on load-bearing walls, is unrivaled.

Creating floors between the first and second floor

The arrangement of wooden floors between floors takes place in several stages, separated by time. If the installation of load-bearing beams is done during the construction of walls, then their further rough sheathing, thermal insulation of floors, fine finishing of the ceiling on the first floor and the floor on the second - much later, when the house is built and covered.

The installation of beams is usually done when the walls are raised to the level of one floor. The masonry of the walls, made along the perimeter, and the erected load-bearing walls represent a horizontal base on which it is convenient to lay out wooden beams with minimal adjustment to one level. First, extreme beams are installed, which are laid, not reaching 5 cm to the vertical surface of the walls. Their relative position during installation is controlled using a water level or a laser level. The intermediate load-bearing elements of the interfloor structure are set in a horizontal plane according to a reference point - a thread stretched between the extreme bars or a long bar installed on top.

Before installation, lumber is treated with antiseptics and solutions (over the entire surface), which reduce the ability of wood to burn. The edges of the beams laid on the walls are processed as described in the previous section. To prevent the bars from moving, they are often fixed to the walls with clamps or wire, after which the laying of the walls of the second floor continues, during which the lumber is finally fixed. Not reaching one or two rows to the final level of the walls (depending on the masonry building material used), in the same way we lay the floor of the second floor along the wooden beams. After the laying is completed, bypassing the installed beams, and on top we form a reinforced concrete reinforced belt, which is the basis for starting the roof structure (mounting the Mauerlat).

Beams are the basis of floors, their bearing part. To make the basis for fine finishing on both floors, it is necessary to create a continuous rough surface, not forgetting to insulate (soundproof) the floors and lay, if necessary, vapor barrier. This is done in this sequence.

1. We roll from below. To do this, it is better to use boards (you can not cut them), which are sewn solid across the beams, fixing them with self-tapping screws. If a layer of vapor barrier material (film) is required, it is attached to the bearing beams of the floor before the roll is formed.
2. The next stage of work is carried out from the side of the upper floor and consists in laying heat-insulating material, which fills the spaces between the beams.
3. After laying the insulation (sound insulator), we form a layer of waterproofing and sheathe the beams. From the side of the upper floor, it is more profitable to sheathe the beams with OSB boards or plywood, which will immediately create the basis for laying the finishing floor material. If you use low-quality boards, you will have to additionally install logs and already form a floor covering on them.

From the side of the lower floor, a crate is made on the basis of roll boards, which is sheathed with plasterboard, decorative or other finishing material. On the upper floor, flooring (laying) of a fine floor covering is carried out.

The possibility of unsupported overlapping of large areas greatly expands the architectural possibilities when designing a house. A positive solution to the beam issue allows you to "play" with the volume of rooms, install panoramic windows, build large halls. But if it is not difficult to block a distance of 3-4 meters with a “tree”, then which beams to use on a span of 5 m or more is already a difficult question.

Wooden floor beams - dimensions and loads

They made a wooden floor in a log house, and the floor is shaking, bending, the effect of a “trampoline” has appeared; we want to make wooden floor beams of 7 meters; you need to block the room with a length of 6.8 meters so as not to rest the logs on intermediate supports; what should be the floor beam for a span of 6 meters, a house made of timber; what to do if you want to make a free layout - such questions are often asked by members of the forum.

Maxinova FORUMHOUSE user

My house is about 10x10 meters. I “threw” wooden logs onto the ceiling, their length is 5 meters, the section is 200x50. The distance between the lags is 60 cm. During the operation of the floor, it turned out that when children run in one room and you stand in another, there is quite a strong vibration on the floor.

And this case is far from the only one.

elena555 FORUMHOUSE user

I can’t figure out which beams for interfloor ceilings are needed. My house is 12x12 meters, 2-storey. The first floor is made of aerated concrete, the second floor is attic, wooden, covered with a bar 6000x150x200mm, laid every 80 cm. When I walk on the second floor, I feel shaking.

Beams for long spans must withstand heavy loads, therefore, in order to build a strong and reliable wooden floor with a large span, they must be carefully calculated. First of all, it is necessary to understand what kind of load a wooden log of one or another section can withstand. And then think over, having determined the load for the floor beam, what kind of rough and finish flooring will need to be done; what will the ceiling be hemmed with; whether the floor will be a full-fledged living space or a non-residential attic above the garage.

Leo060147 FORUMHOUSE user

The load from the own weight of all structural elements of the floor. This includes the weight of beams, insulation, fasteners, flooring, ceiling, etc.
operating load. The operating load can be permanent or temporary.

When calculating the operating load, the mass of people, furniture, household appliances, etc. is taken into account. The load temporarily increases with the arrival of guests, noisy celebrations, rearrangement of furniture, if it is moved away from the walls to the center of the room.

Therefore, when calculating the operational load, it is necessary to think through everything - up to what kind of furniture is planned to be installed, and whether there is a possibility of installing a sports simulator in the future, which also weighs far more than one kilogram.

For the load acting on wooden beams of a long floor, the following values \u200b\u200bare taken (for attic and interfloor floors):

Attic floor - 150 kg / sq.m. Where (according to SNiP 2.01.07-85), taking into account the safety factor - 50 kg / sq.m - this is the load from the floor's own weight, and 100 kg / sq.m - the standard load.

If it is planned to store things, materials and other household items in the attic, then the load is assumed to be 250 kg / sq.m.

For interfloor floors and ceilings of the attic floor, the total load is taken at the rate of 350-400 kg / sq.m.

Overlapping boards 200 by 50 and other running sizes

These are the beams on a span of 4 meters that are allowed by the regulations.

Most often, in the construction of wooden floors, boards and timber of the so-called running sizes are used: 50x150, 50x200, 100x150, etc. Such beams satisfy the standards ( after calculation), if it is planned to block the opening no more than four meters.

For overlapping with a length of 6 meters or more, the dimensions 50x150, 50x200, 100x150 are no longer suitable.

Wooden beam over 6 meters: subtleties

A beam for a span of 6 meters or more should not be made of timber and boards of running sizes.

You should remember the rule: the strength and rigidity of the floor to a greater extent depend on the height of the beam and, to a lesser extent, on its width.

A distributed and concentrated load acts on the floor beam. Therefore, wooden beams for large spans are not designed "end-to-end", but with a margin of strength and allowable deflection. This ensures normal and safe operation of the ceiling.

50x200 - overlap for an opening of 4 and 5 meters.

To calculate the load that the overlap will withstand, you must have the appropriate knowledge. In order not to delve into the strength of materials formulas (and this is definitely redundant when building a garage), it is enough for an ordinary developer to use online calculators for calculating wooden single-span beams.

Leo060147 FORUMHOUSE user

A self-builder is most often not a professional designer. All he wants to know is which beams need to be installed in the ceiling so that it meets the basic requirements for strength and reliability. This is what online calculators allow you to calculate.

These calculators are easy to use. To make calculations of the necessary values, it is enough to enter the dimensions of the lag and the length of the span, which they must cover.

Also, to simplify the task, you can use ready-made tables presented by the gurus of our forum with the nickname Roracotta.

Roracotta FORUMHOUSE user

I spent several evenings to make tables that even a novice builder will understand:

Table 1. It presents data that meet the minimum load requirements for the floors of the second floor - 147kg / sq.m.

Note: since the tables are based on American standards, and the dimensions of lumber overseas are somewhat different from the sections adopted in our country, the column highlighted in yellow should be used in the calculations.

Table 2. Here are the data on the average load for the floors of the first and second floors - 293 kg / sq.m.

Table 3. Here are the data for the calculated increased load of 365 kg / sq.m.

How to calculate the distance between I-beams

If you carefully read the tables presented above, it becomes clear that with an increase in the length of the span, first of all, it is necessary to increase the height of the log, and not its width.

Leo060147 FORUMHOUSE user

You can change the stiffness and strength of the lag upwards by increasing its height and making “shelves”. That is, a wooden I-beam is being made.

Independent production of a wooden glued beam

One solution for long span spans is the use of timber beams in the spans. Consider a span of 6 meters - which beams can withstand a large load.

According to the type of cross section, a long beam can be:

rectangular;
I-beam;
box-shaped.

There is no consensus among self-builders which section is better. If you do not take into account purchased products (prefabricated I-beams), then the simplicity of manufacturing in the "field conditions" comes first, without the use of expensive equipment and tooling.

Just Grandpa FORUMHOUSE user

If you look at the cross section of any metal I-beam, you can see that from 85% to 90% of the mass of the metal is concentrated in the "shelves". The bonding wall accounts for no more than 10-15% of the metal. This is done on the basis of calculation.

What board to use for beams

According to the strength of materials: the larger the cross section of the "shelves" and the further they are spaced from each other in height, the greater the load the I-beam will withstand. For a self-builder, the optimal technology for manufacturing an I-beam is a simple box-shaped design, where the upper and lower “shelves” are made of a board laid flat. (50x150mm, and the side walls are made of plywood with a thickness of 8-12 mm and a height of 350 to 400 mm (determined by calculation), etc.).

Plywood is nailed to the shelves or screwed with self-tapping screws (only not black, they do not cut) and must be glued.

If you install such an I-beam on a six-meter span in increments of 60 cm, then it will withstand a large load. Additionally, an I-beam for a ceiling of 6 meters can be laid with a heater.

Also, using a similar principle, you can connect two long boards, collecting them into a “package”, and then put them on top of each other on an edge (take boards at 150x50 or 200x50), as a result, the beam section will be 300x100 or 400x100 mm. The boards are planted on glue and pulled together with studs or planted on capercaillie / dowels. You can also screw or nail plywood to the side surfaces of such a beam, having previously lubricated it with glue.

Also interesting is the experience of a forum member under the nickname Taras174, who decided to independently make a glued I-beam to block a span of 8 meters.

For this, the forum member purchased OSB sheets 12 mm thick, cut them lengthwise into five equal parts. Then I bought a board 150x50 mm, 8 meters long. With a dovetail cutter, I chose a groove in the middle of the board with a depth of 12 mm and a width of 14 mm - so that a trapezoid with an extension downwards was obtained. OSB in grooves Taras174 glued with the help of polyester resin (epoxy), having previously “shooted” a strip of fiberglass 5 mm wide to the end of the plate with a stapler. This, according to the forum member, would strengthen the design. To speed up drying, the glued area was heated with a heater.

Taras174 FORUMHOUSE user

On the first beam, I trained "filled my hand." The second one was done in 1 business day. At a cost, taking into account all materials, I include a solid board of 8 meters, the cost of a beam is 2000 rubles. for 1 piece

Despite the positive experience, such a "squatter" did not escape several criticisms made by our experts. Namely.