What is a cranial bar. Constructions of wooden beam ceilings Fig.4. Scheme of application of the load on the shield

If the construction of a two-story or one-story house, but with a basement or attic, it is necessary to correctly calculate and build interfloor ceilings. Let's consider the stages and nuances of the overlap according to wooden beams and we will calculate the sections of beams that provide sufficient strength.

The device of interfloor ceilings needs special attention, because, made “by eye”, they may not withstand the loads that fall on them and collapse, or require unnecessary, unreasonable costs. Therefore, one or more options. The final decision can be made by comparing the cost or availability of acquiring materials.

Requirements for interfloor ceilings

Interfloor ceilings must withstand constant and variable loads, that is, in addition to their own weight, withstand the weight of furniture and people. They must be sufficiently rigid and not allow the maximum deflection to be exceeded, provide sufficient noise and heat insulation.

Specific loads from furniture and people for living quarters are taken in accordance with the standards. However, if you plan to install something massive, for example, a 1000 l aquarium or a fireplace from natural stone, this must be taken into account.

The rigidity of the beams is determined by calculation and is expressed in the allowable bending per span. Permissible bending depends on the type of flooring and the flooring material. The main limit deflections determined by SNiP are shown in Table 1.

Table 1

Please note that flooring in the form of ceramic tiles or concrete screed, prone to cracking, can further tighten the requirements for allowable deflection, especially with sufficiently long spans.

To reduce the loads on the beams, if possible, they should be placed parallel to the short walls, with the same pitch. The maximum span when covered with wooden beams is 6 m.

Types of floors

According to the purpose of the overlap are divided into:

• interfloor;
• attic;
• basement (basement).

The features of their design are in the permissible loads and the device of steam and heat insulation. If the attic is not intended for living or storing massive objects, variable loads can be reduced to 50-100 kg / m 2 when calculating the deflection.

Thermal insulation between two residential floors may seem redundant, but sound insulation is a desirable parameter for the majority, and this is achieved, as a rule, with the same materials. It should be taken into account that attic and basement floors need a thicker layer of thermal insulation material. Film material for vapor barrier in the attic floor should be located under the insulation layer, and in the basement - above it. To prevent the occurrence of dampness and damage to structures by a fungus, all rooms must be equipped with ventilation.

Floor options: 1 - plank shield; 2 - vapor barrier; 3 - thermal insulation; 4 - sparse flooring; 5 - boards; 6 - flooring

The design of the floors can also be different:

• with open and hidden beams;
• from various types bearing beams;
• from different materials filling and lining of the floor.

Hidden beams are sewn on both sides and are not visible. Open - protrude from the ceiling and serve as decorative elements.

The figure below shows what the structure of the overlap can be. attic floor with a shield roll and with a filing of boards.

a - with a shield roll; b - with filing from boards; 1 - plank floor; 2 - polyethylene film; 3 - insulation; 4 - vapor barrier; 5 - wooden beams; 6 - cranial bars; 7 - shield reel; 8 - finishing; 9 - filing from boards

Types of fastenings and connections of wooden beams

Depending on the design and material of the load-bearing walls, wooden beams are attached:

• in the nests provided in the brick or block masonry, deepening the beam or log at least 150 mm, and the board at least 100 mm;
• on the shelves (ledges) provided in the brick or block masonry. It is used if the wall thickness of the second floor is less than the first one;
• into cut grooves in log walls to a depth of at least 70 mm;
• to the top rail frame house;
• to metal supports-brackets fixed on the walls.

1 - support on a brick wall; 2 - solution; 3 - anchor; 4 - roofing felt insulation; 5 - wooden beam; 6 - support on wooden wall; 7 - bolt

If the length of the beam is not enough, you can lengthen it by connecting (joining) along the length using one of the known methods using wooden pins and wood glue. When choosing the type of connection, be guided by the direction of application of the load. It is desirable to strengthen the spliced ​​beams with metal plates.

a - compression; b - stretching; c - bend

About wooden beams

In construction, beams of rectangular, round or partially round section are used. The most reliable are rectangular lumber, and the rest are used in the absence of timber or for reasons of economy, if such materials are available on the farm. Glued wood materials have even greater strength. Beams made of glued beams or I-beams can be installed on spans up to 12 m.

The most inexpensive and popular type of wood is pine, but other types of conifers are also used - larch, spruce. Floors are made of spruce in summer cottages, small houses. Larch is good for building premises with high humidity (bath, swimming pool in the house).

The materials also differ in grade, which affects the bearing capacity of the beams. Grade 1, 2 and 3 (see GOST 8486-86) are suitable for floor beams, but grade 1 for such a design may be unnecessarily expensive, and grade 3 is best used on small spans.

Calculation of load-bearing beams

To determine the section and step of the beams, it is necessary to calculate the load on the ceiling. The collection of loads is carried out according to the methodology and taking into account the coefficients set forth in SNiP 2.01.07-85 (SP 20.13330.2011).

Load calculation

The total load is calculated by summing the constant and variable loads, determined taking into account the standard coefficients. In practical calculations, they are first set by a certain design, including the preliminary layout of beams of a certain section, and then corrected based on the results obtained. So the first step is to sketch all the layers of the "pie" overlap.

1. Own specific gravity of the overlap

The specific gravity of the floor is the sum of its constituent materials and is divided by the horizontal total length of the floor beams. To calculate the mass of each element, you need to calculate the volume and multiply by the density of the material. To do this, use table 2.

table 2

For wood-based materials and waste, the density depends on the moisture content. The higher the humidity, the heavier the material.

Permanent loads include partitions (walls), specific gravity which is taken approximately 50 kg / m 2.

The decor of the room, people, animals - all this is a variable load on the floor. According to Table. 8.3 SP 20.13330.2011, for residential premises, the standard distributed load is 150 kg / m 2.

The total load is not determined by simple addition, it is necessary to take the reliability factor, which, according to the same SNiP (clause 8.2.2), is:

• 1.2 - with a specific gravity of less than 200 kg / m 2;
• 1.3 - with a specific gravity of more than 200 kg / m 2.

4. Calculation example

As an example, let's take a room with a length of 5 and a width of 3 m. Every 600 mm of length we put beams (9 pcs.) Of pine with a section of 150x100 mm. We will block the beams with a board 40 mm thick and lay linoleum 5 mm thick. From the side of the first floor, we will sew the beams with plywood 10 mm thick, and inside the ceiling we will lay a layer of mineral wool 120 mm thick. Partitions are absent.

1 - beam; 2 - board; 3 - insulated linoleum 5 mm

The calculation of the constant specific load on the area of ​​​​the room (5 x 3 \u003d 15 m 2) is shown in table 3.

Table 3

Design load on the beam (qр) - 250 x 0.6 m = 150 kg / m (1.5 kg / cm).

Allowable deflection calculation

We accept the permissible deflection of the interfloor ceiling - L / 250, i.e. for a three-meter span, the maximum deflection should not exceed 330 / 250 = 1.32 cm.

Since the beam lies on the support at both ends, the calculation of the maximum deflection is carried out according to the formula:

• h = (5 x qp x L4) / (384 x E x J)

For our example:

• h \u003d (5 x 1.5 x 3304) / (384 x 100000 x 2812.5) \u003d 0.82 cm

The result obtained in comparison with the allowable deflection has a margin of 60%, which seems excessive. Therefore, the distance between the beams can be increased by reducing their number and repeat the calculation.

In conclusion, we suggest watching a video on calculating the floor on wooden beams using a special program:

The cranial bar is a material that is fixed on the side face of a wooden beam, as a result of which floor panels rest on it. It is used both in civil and residential buildings, while it is important to observe that the cranial and wooden beams are in the same plane.

To fasten the bars, nails of a certain diameter are used. At the same time, they must be hammered at a certain distance and in the center of the bar.

The cranial bars are a kind of supporting structure, to which all kinds of Decoration Materials, for example, wall lathing, or lathing used for laying tiled roof. It is also possible to use them in the frame of a wooden fence. The price of this material varies from 15,000 per 1m 3.

Beam production

In most cases, the beam is made of pine, with the help of a special machine it is processed from all sides. The most common dimensions of the cranial bar are 40x50 mm.

Its production is carried out in two main ways:

1. Standard edged method - production is carried out from wood of normal humidity;
2. Dry planed method - involves the manufacture of timber from wood with a moisture content of 8-10%. It is first dried using a special drying chamber, where all bacteria die.

Important!
Before use, the bar must be treated with a bioprotective agent - this can significantly increase its operational life.

Calculator

Simple calculation calculator required amount bar looks like this:

Wall length

m

Wall width

m

Wall height

m

Bar section

150x150 mm. 180x180 mm. 200x200 mm.

Beam length

5 m 6 m 7 m 8 m 9 m 10 m 11 m 12 m

Floor device

The cranial bar is quite widely used in the process of constructing a "rough" floor. The bars are attached to the floor joists and subsequently they serve as a support for it. This is the easiest and fastest way.

Essential elements

Basement or floor, consist of the following elements:

1. Beams - girders, which are based on the plinth strapping, or on the crown crown (in log cabins);
2. Logs - beams laid across the runs;
3. "Black" floor (rewind);
4. Backfill - insulation;
5. Clean floor.

The main load-bearing element of the floor are the girders, they provide the required structural rigidity.

Floor logs - beams with cranial bars

Important!
The overlap must withstand a load of about 200 kgf per 1 m 2 of surface (in addition to its own weight, which is approximately 60 kgf per 1 m 2).
If this condition is met, the operation of the building is allowed.

Flooring device

1. For this, a material with a thickness of 5-8 cm is used, if a greater thickness is required, then double products are taken, however, it is allowed to use a solid beam, or a log cut with at least one edging;
2. Cranial bars 4x4 cm are fixed on the bottom of the beam-run. This is done in order to support the roll, on which it will subsequently be laid;
3. If the log is being hewn for use as a beam, it is advisable to cut out the cranial profile at once as well;
4. The girders were cut into the crown or laid on the plinth, their horizontalness (using a hydraulic level) and flatness (using a cord stretched over the extreme girders or a long rail) was checked. As a result, the top edges of all beams must be in the same plane (horizontal);
5. Now it is necessary to lay a roll over the cranial bars. As a reel, a slab or board is perfect;

1. Then glassine is laid on top of the roll as follows, and its edges should be bent vertically upwards so that it can be nailed to the beams without problems;
2. If the runs are located quite densely, it is allowed to lay the floor boards directly on them, after installing the insulation and the top layer of glassine;
3. If the runs are more than 1.2 m apart, then logs from a bar (50x80 or 50x100 mm) are laid across the beams in increments of approximately 0.6-1.2 m. In this case, the logs will act as a support for the boards clean floor.

Laying the floorboard

Installation instructions:

1. At the wall across the lag, an extreme board is nailed. After that, 6-8 boards are laid, squeezed out (rallyed) along the length of the board in 2-3 places. Thus, the maximum adjoining of boards to each other is provided. Further, with the help of nails, the boards are nailed into each log, and the spin is removed. Then the operation must be repeated;
2. There are various methods for rallying the structure. The simplest is with the help of building brackets. These devices are driven into the logs, after which two wedges are driven in between the extreme board and the bracket (the gasket and the working wedge are made of birch);
3. Instead of wedges, you can support the board on staples, and wring out with a vertical lever. Special wedge clamps or tee brackets are much more convenient.

In addition, there are tension devices that are used in mass construction. Unlike wedges, they are much more efficient (it takes less time to spin). A jack (not hydraulic) is perfect as a wringing mechanism.

Attic floor installation

The device of the attic floor is carried out similarly to the basement:

1. Run-beams are cut into the crown of the log house at the required height. When frame structure, they rest on a horizontally located board (width - 100 mm, thickness - 50 mm), cut into vertical racks flat flush;
   
2. After that, the ceiling is hemmed from below along the cranial bars. On top of the lags, the floor of the second floor or attic is being installed. If the use of the attic floor is not provided, then, as a rule, the floor is not laid.

Results

Summing up, it should be noted that at present the bulk of people during the construction country houses uses not a brick, but a tree, wooden structures made of timber are especially popular. The video in this article will help to consider in more detail the technology of laying tile bars.

Wooden floors ( fig. 1) in most cases consist of load-bearing beams, floor, inter-beam filling and finishing layer of the ceiling. Sound or heat insulation is provided by a flooring, which is called a reel.

Beams are most often wooden bars rectangular section. For reeling it is advisable to use wooden shields. In order to save wood, plank rolls can be replaced with rolls from ribbed or hollow gypsum or lightweight concrete blocks. Such elements are somewhat heavier than wooden rolls, but they are non-flammable and do not rot.
To ensure better sound insulation from airborne sound transfer along the reel, a clay-sand lubricant 20-30 mm thick is made, on top of which slag or dry calcined sand 6-8 cm thick is poured. The porous material backfill absorbs some of the sound waves.
The design of a wooden floor includes a flooring made of planed tongue-and-groove boards, nailed to the logs, from plates or boards, which are laid across the beams every 500-700 mm.

Wooden floor beams

The bearing elements of the beam ceilings are wooden beams of rectangular section with a height of 140-240 mm and a thickness of 50-160 mm, laid through 0.6; 0.8; 1 m. The cross section of the wooden floor beams depends on the load, filing (rolling) with backfill, and the plank floor laid on the logs as directly on the logs (Table 1.).

Table 1. Minimum section of wooden beams of a rectangular floor

The use of hardwoods as floor beams is not acceptable, as they do not work well in bending. Therefore, coniferous wood, peeled from bark and antiseptic without fail, is used as a material for the manufacture of wooden floor beams. Most often, the ends of the beams are inserted into nests specially left for this purpose in brick walls ah directly in the process of masonry ( rice. 2 a. or fig. 2 b.), or cut into the upper crown of log, block and frame-panel walls.

The length of the supporting ends of the beam must be at least 15 cm. The correct position of the extreme beams is checked by a level or spirit level, and the intermediate ones - by a rail and a template. The beams are leveled by placing tarred scraps of boards of different thicknesses under their ends. It is not recommended to lay chips or trim the ends of the beams.
Wooden floor beams are laid, as a rule, along a short span section, as parallel as possible to each other and with the same distance between them. The ends of the beams, resting on the outer walls, are cut obliquely at an angle of 60 degrees, antiseptic, burned or wrapped with two layers of roofing felt or roofing felt. When embedding wooden beams into nests in brick walls, we recommend that the ends of the beams be treated with bitumen and dried to reduce the likelihood of rotting from moisture. The ends of the beams must be left open. Spatial niches when sealing wooden floor beams are filled around the beam with effective insulation (mineral wool, polystyrene). With a brick wall thickness of up to 2 bricks, the gaps between the ends of the beams and the brick wall are filled cement mortar. It is also possible, as an option, to insulate the ends of the beams with wooden boxes, having previously tarred them. In thick walls (2.5 bricks or more), the ends of the beams are not covered, leaving ventilation holes. This prevents the ends of the beams from moisture condensation. Diffusion of moisture in a wooden beam is shown in fig. 3.

When supporting beams on internal walls two layers of roofing felt or roofing material are placed under their ends.
Every third beam embedded in the outer wall is fixed with an anchor. Anchors are attached to the beams from the sides or from the bottom and embedded in the brickwork.
In the absence of a beam of a suitable section, boards knocked together and placed on the edge can be used, while the total cross section, in comparison with the whole beam, should not decrease.

In addition, logs of the appropriate diameter, hewn on three sides, can be used instead of block beams, which is more economical (roundwood is much cheaper than lumber), but in this case the logs must be aged in a dry room for at least one year, like a log cabin.
To enhance the bearing capacity of the floor, a cross scheme for installing power beams can be used. When applying such a scheme, the floor rests on all the walls of the building along the contour. The nodes of the intersections of the beams are pulled together with clamps or wire twists. Cross slabs are used extremely rarely, since it is much easier to reduce the pitch of the supporting beams and make an ordinary slab, but less lumber is used to make a cross slab than a traditional one, with the same bearing capacity of the slabs.
Structural differences between floors are observed when they are insulated (Fig. 1.). The interfloor overlap is not insulated, the attic (with a cold attic) is insulated with the device of the lower vapor barrier layer, and the basement is insulated with the device of the upper vapor barrier layer.

Roll forward

The next step in the construction of floors is the roll-up flooring. For its fastening, cranial bars with a section of 5 x 5 cm are nailed to the beams, directly on which the rolling boards are laid. (Figure 4.)

The roll plates are tightly adjusted to each other, removing all the gaps between the individual boards. Strive to ensure that the lower surface of the roll is in the same plane as the floor beams. To do this, it is necessary to select a quarter (fold) in the roll-up boards. For the construction of the roll, it is not necessary to use full-fledged boards, they can be completely replaced with a croaker. The filing of boards with a thickness of 20-25 mm is fixed with nails hammered at an angle. As we have already noted, fiberboard, gypsum-slag and other lightweight concrete slabs can be used instead of boards for rolling, which increases the fire resistance of floors. The laid reel is covered with a layer of roofing felt or roofing material and covered with or laid insulation: as in the walls, here you can use mineral wool, sawdust, slag. When insulating floors, loose insulation is not tamped, and they are backfilled at the height of the beams. The type of insulation and its thickness are determined from the calculated outdoor air temperature, using the data in Table 2.

Table 2. The thickness of the backfill of the attic floor, depending on the outside temperature

Lastly, the upper face of the beams is covered with roofing felt or roofing material, and logs are placed on top. Note that the lags are not a mandatory element of the overlap. Laying a log is economically justified if the beams have a rare arrangement.

We also draw your attention to what elements of the floors will be superfluous in the construction of basement and attic floors:
- there is no lining in the basement
- in the attic floor there is no lag and a clean floor

The basement can be designed in such a way that the run-up and insulation will be superfluous (of course, without compromising performance), however, in this case, roofing material will be required over the entire floor area, and the backfill will be gravel or compacted rubble (Fig. 5.)

Chimney device (chimney)

In places where wooden floors come into contact with smoke channels, cutting is arranged (Fig. 6.)

The distance from the edge of the smoke channel to the nearest wooden structure is assumed to be at least 380 mm. Ceiling openings in the places where chimneys pass are sheathed with fireproof materials. In places of overlap in chimneys, cutting is arranged - thickening of the pipe walls. Within the groove wall thickness chimney increases to 1 brick, that is, up to 25 cm. But in this case, the floor beams should not touch brickwork pipes and stand at least 35 cm from the hot surface. This distance can be reduced to 30 cm by laying felt or asbestos cardboard 3 mm thick between the cutting and the beam soaked in a clay solution. The end of the shortened beam, located opposite the groove, is supported on a crossbar suspended on clamps (Fig. 7.) to two adjacent beams.

Economic overlap

Economical is considered an overlap consisting of wooden shields with one-sided and two-sided sheathing, which, together with the frame of the shields, perceives vertical loads. The sheathing can perform a load-bearing function only if it is firmly connected to the ribs of the boards of the shield frame. The ribs and skins are tightly connected to each other and have a high load-bearing capacity.

Chipboard and construction plywood proved to be excellent as cladding. Boards are also suitable for this, but, however, due to the large number of equally oriented seams, they do not contribute to an increase in the bearing capacity of the floor.

Gypsum fiber or gypsum boards cannot be considered as additional load-bearing elements. Not able to bear the load and sheet materials such as cement particle board and blockboard. In addition, they are much more expensive than chipboard and plywood. On fig. 8 shows several options for the arrangement of floors.

Rice. 8. .

Methods for calculating wooden floors

Previously, the load-bearing capacity of floors was determined by master builders, guided by their experience. Often this let them down, especially when erecting buildings of complex configuration, which led to the collapse of buildings.
In our time, computer technology has come to the aid of builders, providing, together with achievements in the field of materials science, high calculation accuracy. On fig. 9, as an example, the results of the calculation of the floors shown in fig. 8 .

It can be seen that despite the smaller thickness of the beams in the frame (by almost 40%), the shields can cover approximately the same spans as wooden beams. The maximum allowable width of the room and the width of the span in our case is about 6 m.

For single- and double-span structures, if the calculated values ​​are exceeded, additional supports are required under the ceiling, which significantly increases the cost of the structure.
For a single-span ceiling, where the shields lie on supports only with the ends of the stiffeners, the span width, which is somewhat larger than the clear width of the room, should not exceed approximately 5 m. For a double-span ceiling, the allowable span width and, accordingly, the room increases to 6 m.

In many projects offered by various companies, the depth of the house is determined by a two-span ceiling. The width between the longitudinal walls of the house usually ranges from 9 ... 12 m, and a load-bearing wall is placed in its middle. When calculating floor structures, first of all, its own weight is determined. In the variant shown in Fig. nine , it is taken equal to 100 kg/sq.m., as is often the case. Additional load (weight of the inhabitants of the house and interior furnishings) take equal to 275 kg / sq.m.. Light partitions installed on the floor without any static calculations are also taken into account. Such a load could be created, for example, in a situation where, on a floor area of ​​20 sq.m. accommodate 73 people at the same time. This simple example shows that the regulatory indicators are focused on the unconditional safety of the inhabitants of the house. When calculating wooden structures usually provide a triple margin of safety, excluding the likelihood of their collapse. In other words, in a room with a total area of ​​\u200b\u200b20 sq.m., that is, with dimensions of 5.90 x 3.40 m (see the allowable span width indicated in Fig. 9), 220 people could be accommodated, which, of course, just unrealistic. However, this example suggests that the calculated bearing capacity of the floor is so high that a fireplace, shelves, a tiled stove, a waterbed, an aquarium and much more can be safely placed on this floor.

Deflection limit under standard load

However, even under the normative load, the floor sags, which can be felt even when walking on it. To avoid these unpleasant sensations, the deflection of the ceiling must be no more than 1/300. This means that with a span width of 6 m, the floor can sag under the standard load (even if it occurs only in exceptional cases) no more than 2 cm.

Overlapping, of course, can bear a load no more than that which is allowed by loaded walls, lintels and supports. In this regard, a developer who does not have the appropriate specialized knowledge, who intends to place heavy structures or objects on the floor, should seek advice from a specialist in static calculations of the stability of building structures.
Overlapping gives the building additional rigidity. Wind loads acting on the building through the roof, on the gables and external walls, are transmitted through the ceiling to the entire structure of the building. To compensate for these loads, the upper cladding of the floor is strengthened. When laying individual floor beams, sheathing slabs (usually made of chipboard) are placed with mutual displacement of the seams and attached to the beams. When using ready-made floor elements, which is customary in the construction of prefabricated houses, they are firmly connected to each other, and along the edges - with a bearing support (walls, partitions).
If the size of the building on any of the facades exceeds 12.5 m, additional load-bearing partitions are required to give it the required rigidity. These walls must again be connected to the ceiling.

In contrast to the thermal insulation of the interfloor ceiling, which is of secondary importance, special attention is paid to its sound insulation. Structures with good strength, unfortunately, do not always meet the requirements for noise protection. Designers working in the construction of prefabricated houses have to solve a controversial problem: the creation of statically reliable connections on the one hand, and on the other - and at the same time "soft" disconnected structures that provide optimal sound insulation.
Beams with rolling and filling with expanded clay or slag (Fig. 10 a, b) no longer meet the requirements either in terms of work technology, or in terms of sound insulation and a number of other problems.

The new standards were forced to include requirements for improving protection against impact noise, even to the detriment of the bearing capacity of structures. In order to jointly solve the problem of sound insulation, specialists from the field of prefabricated housing construction and the production of gypsum and insulating boards sat down at the same table. As a result, new designs were created, which were soon included in the norms (Fig. 11).

Rice. eleven. Overlapping options according to current standards with attenuation of airborne noise up to 52 ... 65 dB and shock - up to 7 ... 17 dB: 1 - grooved chipboard; 2 - wooden beams; 3 - gypsum boards; 4 - fibrous insulating board; 5 - fibrous insulating mat or plate; 6 - dry sand; 7 - rack lathing, in which the distance between the rails along the axes is 400 mm and fastened with spring brackets; 7a - wood boards; 8 - connections with self-tapping screws or glue; 9 - sound-absorbing floor covering; 10 - logs with a section of 40x60 mm; 11 - gypsum boards 12 - 18 mm thick or chipboard 10 ... 16 mm thick; 12 - concrete slabs laid on cold bitumen; 13 - sheathing from tongue-and-groove boards.

For the first time, the conversation turned to the use of the so-called spring brackets, which separate the beams and the lower cladding of the ceiling. (Fig. 12)

Practice has shown that this innovation has led to a decrease in the noise level by about 14 dB - a result that deserves attention. To improve sound insulation, it is necessary to place weighting agents inside the ceilings of this design, for example, sand, concrete slabs of various shapes and other materials that reduce the transmission of high-frequency sounds.
The disadvantages of backfilling with sand are the likelihood of it spilling through the seams and holes into the underlying rooms. But this can be prevented, for example, by laying a film or special mats. These mats consist of two films welded together, between which sand is located.
Instead of sand, cement-based boards can also be used. The disadvantage of these solutions is that such fillers are heavy, which requires more durable beams to the detriment of the cost-effectiveness of structures.
Make a ceiling with open (that is, not sheathed from below) wooden beams that would provide reliable protection from noise, today it is hardly possible. New scientific research positive results unfortunately they didn't. So the question of the perfection of noise-protecting structures is waiting to be decided.

Weather protection

In special protection against climatic influences, wooden structures of the outer wall, flat roof, floors of the attic (technical) floor or attic with sloping walls with a good roof is not needed. The protection of wood between floors is important only in "wet" rooms (as a rule, in the shower area, bathrooms, laundries and baths). The ceiling does not need ventilation at all, therefore, it should not be taken into account.
For all the structures of non-ventilated floors presented in the article, including for open beams, it is quite sufficient to protect the wood with paintwork or other finishes. Special chemicals are not needed here.

Fire protection of floors

Special requirements for building materials and structures are imposed by fire protection standards. All materials are divided into combustible and non-combustible. Structures made of materials of various properties are distinguished, if possible, by delaying fire for some time (semi-fire-resistant) and completely preventing the spread of fire (fire-resistant). These characteristics are fixed in building codes.
In residential construction, in particular, in buildings where the floor of the upper floor is located more than 7 m from ground level, the structures of the interfloor ceiling must have at least fire-retarding properties (the duration of fire resistance is at least 30 minutes under experimental conditions). For the manufacture of wooden structures, it is allowed to use solid wood and other wood materials of ordinary sizes and density. However, in public buildings, wood is treated with solutions that make it fire resistant. Naturally, non-combustible materials can also be used, in particular, gypsum fiber and gypsum boards.
Typical examples of ceilings made of wooden boards with fire insulation are shown in fig. 12.

When designing ceilings on open wooden beams ( fig. 13), it is also necessary to take into account the fact that these beams are exposed to fire not only from below, but also from the sides.
When determining the resistance parameters of structures made of solid wood (for example, coniferous), its burnout rate is assumed to be 0.8 mm / min.
When calculating floors for open wooden beams 24 cm high with a span width of 5.80 or 5.85 m, the width of the beams is increased to 120 mm or more, so taking into account fire resistance, they must be selected with a cross section of 11x24 cm.
Based on the foregoing, we can conclude that with regard to the reliability of sound insulation and fire safety there are still enough questions to cover and in the coming years they will have to be solved by the joint efforts of scientists, designers, manufacturers building materials, designers and builders.

Increasing the bearing capacity of floor beams

The bearing capacity of floor beams can be increased if necessary. Increasing the cross section of the beams by attaching thick boards to them, the ends of which, like the beams, must lie on the supports, is one of the most common ways to solve this problem.

Rice. fourteen. .

U-shaped steel channels can also be used by bolting them to the side of the beam. The advantage of this method is that it will be enough to open the floor beams ("bare") for fastening on only one side.
But, perhaps, the simplest, but requiring serious labor, will be to strengthen the overlap by laying additional beams (between the existing ones) that cover the span from support to support.
In most old houses, the section of the floor beams is sufficient (and even with a margin) and they are laid with a small step, which indicates good construction.
The condition of the beams and floors must be checked in any case. Beams damaged by pests and moisture, and therefore weakened, should be strengthened.
With prolonged exposure to moisture due to leaks in the area of ​​​​overhangs, damage to the heads of the beams on the supports is not excluded. In this case, it is better to remove the damaged part of the beam to healthy wood, and reinforce and lengthen the remaining part with overlays from sufficiently thick boards that provide the required strength.

A clean floor and filing are elements of an interfloor overlap, but they belong to the category of finishing work. Therefore, we will talk about them in the next article.

TYPICAL TECHNOLOGICAL CHART (TTK)

DEVICE OF FLOORS FROM WOODEN BEAMS WITH SHIELD ROLLING

I. SCOPE OF THE MAP

The technological map was developed for the installation of an interfloor ceiling consisting of wooden beams with a shield roll of 30 m2 in a wooden two-story building.

Rice. 1. Details of interfloor overlap with shield roll

a - beam support unit on the wall; b - cross section of the floor;

1 - plinth; 2 - floor; 3 - lag; 4 - beam; 5 - backfill or mineral wool; 6 - clay lubricant or roofing layer; 7 - shield reel; 8 - cranial bar; 9 - bar for fixing the beam; 10 - insulation.

The map provides for the performance of work using a light mobile crane MBTK-2.

Rice. 2. Installation of the ceiling

1 - pipe valve MBTK-2; 2 - beam with cranial bars; 3 - mounting tables; 4 - installation of beams on the first plot

When linking the map to specific repair conditions, the scope of work, the scheme of mechanization, the calculation of labor costs, the schedule for the process, and technical and economic indicators are specified.

II. TECHNICAL AND ECONOMIC INDICATORS

Labor intensity for the entire scope of work:

normative 8.1 man-days

accepted 7.3 man-days

Labor intensity per 100 m of overlap:

normative 27.1 man-days

accepted 24.4 man-days

Average output per worker per shift:

normative 3.7 m overlap

assumed 4.1 m overlap

III. TECHNOLOGY OF THE CONSTRUCTION PROCESS

1. Prior to the commencement of work on the installation of the floor, the following must be performed:

a) disassembly of the roof over the area where the replacement of floors is carried out;

b) dismantling of old floors (with the preservation of old beams through one);

c) replacement of rotten wall crowns;

d) dismantling or hanging partitions.

Rice. 3. Wooden beams with cranial bars for floors

a - general view;

b, c - cross-sections of beams of the BD and BO type (dimensions in mm);

1 - fastening the bars to the beam

3. The overlap device is made in the following order:

a) install scaffolds from inventory elements on the floor of the first floor;

b) cut out motorized or electric chain saw rotten sections of the crowns near the supports of the beams and close up the holes from the removed beams;

c) according to preliminary marking, they are cut down and cut into outer wall rectangular sockets for supporting new beams; in the middle wall cut through nests.

IN individual cases in the absence of a middle wall, through nests are cut out in one of the outer walls. The width of the through nest should be 5 cm larger than the corresponding size of the section of the beams;

d) the ends of the beams before laying, except for the ends, are coated with resin and wrapped with antiseptic felt;

e) beams are fed to the place of decline with the help of a crane, one end is inserted into a through nest, the other end is lowered and pushed into a nest in the opposite wall; in a through nest, the beam is firmly fixed by: driving wedges; the horizontal laying of the beams is checked by a level; the gaps between the end of the beam and the walls of the nest are tightly clogged with tow. The beams are supported when bypassing the chimneys using crossbars and metal pockets suspended from the beams.

Rice. 4. Supporting beams on crossbars

f) as new beams are laid, the beams left temporarily to ensure the rigidity of the building are removed, replacing them with new ones as well;

g) the laying of the roll-over shields is carried out after the laying of the beams from the temporary flooring from the boards laid along the beams;

h) after laying the reel, a layer of roofing is laid and the ceiling is backfilled with calcined sand (slag, expanded clay). Backfilling of bulk materials is carried out using containers with a capacity of 0.5 m3 with an opening bottom;

i) bulk materials delivered to a newly constructed wooden floor must be carefully leveled with a layer in thickness in accordance with the design decision

4. When performing work, the following must be observed safety rules:

a) access to the premises where work is carried out must be closed;

b) floors should not have unenclosed openings;

c) it is forbidden to overload the floors with construction debris, materials from dismantling;

d) it is forbidden to work on the reel, as well as to put materials on the reel;

e) it is forbidden to stand on the ceiling lining after the roll has been removed.

5. Requirements for the quality of work

a) the work performed must comply with the project and not have deviations exceeding the following values:

in cross sections of beams ±10 mm

in distances between beams ±10 mm

at the bottom faces of the beams:

per 1 m length 2 mm

for the whole room 10 mm

b) for the laid prefabricated structures, the acceptance commission must be presented with the manufacturer's passports.

IV. ORGANIZATION OF WORKERS' LABOR

1. The composition of the link of workers (3 people):

installers (carpenters):

5 digits - 1 2 digits - 1

3 digits - 1

2. Distribution of work between performers:

a carpenter of the 5th category marks the places for laying new beams, prepares beams and roll-up boards for laying in the ceiling, participates in laying beams and roll-up boards, lays an insulating layer;

a carpenter of the 6th category cuts holes and nests in the walls for laying beams (if old ones are not used), participates in laying beams and roll-up shields;

a carpenter of the 2nd category closes up holes from dismantled beams, participates in laying shields, arranges clay lubricant or spreads roofing, falls asleep insulation.

The work organization scheme is shown in fig. five.

Rice. 5. Scheme of organization of work

1 - pipe valve MBTK-2; 2 - roll-over shields; 3 - beams; 4 - wooden beds for crane movement; 5 - insulation;

b - clay solution;

I-IV - successive stages of installation

V. MATERIAL AND TECHNICAL RESOURCES

Table 1

VI. Schedule of work on the installation of floors from wooden beams with shield rolling on an area of ​​30 m

table 2

VII. Calculation of labor costs for the installation of floors from wooden beams with shield rolling

Table 3

During the construction of private low-rise buildings wooden floors are most often erected from wood, concrete blocks or bricks between 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 heated and living quarters, 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, sound absorbing panels ZIPS, soundproof membranes (Tecsound), etc. When using materials capable of absorbing water vapor (basalt wool, glass wool), a vapor barrier film, and on top of the sound insulator - waterproofing.

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 a "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. The sides of the groove can be covered with crushed stone or covered with cement mortar by 4-6 cm. Every fifth beam is additionally fastened to the wall with an anchor.

IN 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 entire 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 of wooden structures to rot and ensure fire safety.

2. The ends of the beams are cut at an angle of 60 °, they are painted with bituminous mastic and wrapped with roofing material 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 on their upper plane on the edge, and a bubble level is placed on top of it. 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 creaking of the beam and block the access of cold air, the gap is filled with 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 of a 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.