Nodes of support of floor beams on foundation walls. How to support a beam on a brick wall

Wood has been used at all times and is still preferred in private homes today.

Wooden floors are laid according to a long-established technology and most often consist of load-bearing beams, a floor, interblock filling and a layer with which the ceiling is finished. Noise - and thermal insulation provides flooring, which is called the coast.

A beam is a rectangular cross-section of a wooden beam, a reel is a flooring made of boards or shields, sometimes they can be replaced with heavier fire and rot-resistant hollow blocks of gypsum or lightweight concrete.

To ensure better sound insulation from airborne noise, a clay-sand lubricant 20–30 mm thick is arranged along the reel, on top of which a layer of slag or 6–8 cm of dry calcined sand is laid. Backfill from porous material absorbs part of the sound waves, but, frankly, such sound insulation does not comply with modern building codes.

Wooden floor beams

The wooden beams used in the beam ceiling have a rectangular section and the following dimensions: height 140 - 240 mm and thickness 50 - 160 mm, they are laid through 0.6; 0.8; 1 m. The cross-section of wooden beams is selected depending on the load, rolling with backfill and the floor of the boards laid on the logs.

Beams are made exclusively from conifers wood, as hardwood does not bend well. Of course, the beams must be cleaned of bark and impregnated with antiseptics. Beams can not be sheathed, then they will carry in the interior of the house not only a utilitarian function, but also an aesthetic one.

If it is impossible to use a beam due to any reason, then boards placed on the edge can be used as a replacement, but in no case should the cross section be reduced compared to a solid beam. In addition, the timber can be replaced with logs hewn on three sides of the appropriate diameter, which is even more economical, as roundwood not as expensive as lumber, only in this case the logs must be kept in a dry room for at least a year, like a log cabin.

Laying beams

Usually, the ends of the beams are brought into the nests specially left for this in the brick walls right during the construction of the house or are cut into the upper crown of the log, cobbled and frame-shield walls. At the same time, the beam goes into the niche by at least 15 cm.

Laying of beams starts from the upper points, then intermediate ones are laid. 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 lining under the ends of the tarred scraps of boards of various thicknesses, at the same time it is undesirable to use chips for this purpose or to trim the ends of the beams.

For convenience, the beams are laid across the length of the house, parallel to each other, keeping the same distance between them. The ends of the beams, resting on the outer walls of the house, are cut obliquely at an angle of 60 °, and without fail treated with antiseptics and wrapped with two layers of rolled waterproofing material. In the case of embedding floor beams in nests of brick walls, it is advisable to treat the ends with bitumen and dry to prevent possible decay. The ends of the beams should not be covered with anything, it is best to leave them open.

If the thickness of the brick walls is up to 2 bricks, then the gaps between the ends of the beams and the brick wall are closed cement mortar. In addition, it is desirable to insulate the ends of the beams with the help of wooden, pre-tarred boxes. In walls with a thickness of 2.5 bricks or more (thick walls), the ends of the beams are not covered, ventilation holes are left.

When supporting beams on internal walls waterproofing material is 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.

If the house needs a reinforced floor system, then the so-called cross installation of power beams is used - this option is used quite rarely, but if you talk about it, then it’s worth revealing the essence. When using such a system, the ceiling rests on all the walls of the house along the contour. The intersection nodes of the beams are pulled together with clamps or wire twists. More often, the issue of strengthening the overlap is solved more simply - the step of the supporting beams is reduced.

Warming and soundproofing

after the beams are laid and hemmed, a heater is placed in the niche between them. It can be mineral wool, expanded polystyrene, ecowool, etc. The insulation is protected from below and from above by a film.

It is necessary to insulate the ceiling only then, only in the case of separation of an unheated attic space from residential premises. Interfloor ceilings are not insulated. Interfloor ceilings can not be insulated, but it is desirable to soundproof them. Structures with good strength, unfortunately, do not always meet the requirements of soundproofing residential premises.

Beams with rolling and expanded clay filling do not meet the requirements either in terms of work technology or in terms of sound insulation.

In the manufacture of interfloor and attic floors on wooden beams, it is necessary to take into account constant loads, that is, the own weight of structures and coatings (mainly 200 - 300 kg / m2) and variable, live loads, that is, loads that occur during operation (taken equal to the average value 200 kg/m2).

Table of cross-sections of wooden floor beams, depending on the span and step-by-step installation of beams with a total load of 400 kg / m2.

Span length, m	Beam spacing 0.6 m	Beam spacing 1 m
2,0	75x100 mm	75x150 mm
2,5	75x150 mm	100x150 mm
3,0	75x200 mm	100x175 mm
4,0	100x200 mm	125x200 mm
4,5	100x200 mm	150 x200 mm
5,0	125x200 mm	150x225 mm
5,5	150x200 mm	150x250 mm
6,0	150x225 mm	175x250 mm
6,5	150x300 mm	200250 mm
7,0	150x250 mm	200x75 mm

Walls made of gas silicate blocks

In no case should wooden floors be fixed with anchors to gas silicate blocks - gas silicate does not like point loads. Due to its softness, the gas silicate will not hold the anchors, they will begin to slowly loosen. In addition, the load from the wooden floor beams is directed not only downwards, but also to the sides. They will simply force the walls of your house at one not-so-great moment to disperse to the sides.

In order to give rigidity to the entire frame, as well as to evenly distribute the load immediately on the entire perimeter of the wall of the house from gas silicate blocks, it is necessary to install an armored belt. Because, then it may happen that somewhere one edge or corner will press more due to the slightest level deviation ... In addition, the beam, no matter how smoothly it is laid, will “move” seasonally from variable temperature effects, other loads, thus making a nest for itself much larger than you have defined for it. And in the case when it is laid on the armored belt, gas silicate blocks will feel more comfortable.

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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

Width span, m	Distance between beams, m
	0,5				1

	1,5 (150)	2,5 (250)	3,5 (350)	4,5 (450)	1,5 (150)	2,5 (250)	3,5 (350)
2,0	5 x 8	5 x 10	5 x 11	5 x 12 (10 x 10)	10 x 10	10 x 10	10 x 11
2,5	5 x 10	5 x 12 (10 x 10)	5 x 13 (10 x 11)	5 x 15 (10 x 12)	10 x 10	10 x 12	10 x 13
3,0	5 x 12 (10 x 10)	5 x 14 (10 x 11)	5 x 16 (10 x 13)	5 x 18 (10 x 14)	10 x 12	10 x 14	10 x 15
3,5	5 x 14 (10 x 11)	5 x 16 (10 x 13)	5 x 18 (10 x 15)	10 x 16	10 x 14	10 x 16	10 x 18 (15 x 16)
4,0	5 x 16 (10 x 13)	5 x 18 (10 x 15)	10 x 17 (15 x 15)	10 x 18 (15 x 16)	10 x 16	10 x 19	10 x 21 (15 x 19)
4,5	5 x 18 (10 x 14)	10 x 17 (15 x 15)	10 x 19 (15 x 17)	10 x 20 (15 x 18)	10 x 18	10 x 21	10 x 23 (15 x 21)
5,0	10 x 16	10 x 19 (15 x 16)	10 x 21 (15 x 18)	10 x 23 (15 x 20)	10 x 20	10 x 23	10 x 26 (15 x 23)

Usage hardwood wood 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 directly during the laying process ( 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 beams are laid using the “beacon” method - first, the extreme beams are installed, and then the intermediate ones. The correct position of the outer 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 with 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 beams are supported 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 house.
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. The cross-slab is used extremely rarely, since it is much easier to reduce the pitch of the supporting beams and make an ordinary floor, but less lumber is used to make a cross-slab than a traditional one, with the same load-bearing capacity of the floors.
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, instead of boards for rolling, you can use fiberboard, gypsum slag and others easily. concrete plates, which increases the fire resistance of floors. The laid roll is covered with a layer of roofing felt or roofing material and filled 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

Material	Volume weight, kg/m³	Backfill thickness (mm) at outdoor air temperature, °C
Material	Volume weight, kg/m³	-15	-20	-25
sawdust	250	50	50	60
Wood shavings	300	60	70	80
Agloporite	800	100	120	140
Boiler slag	1000	130	160	190

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 log and a clean floor

The basement ceiling 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 cutting limits, the wall thickness of the chimney increases to 1 brick, that is, up to 25 cm. But even 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 3 mm thick felt or asbestos cardboard soaked in a clay solution between the groove and the beam. 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. 9 , 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, a triple margin of safety is usually provided, excluding the possibility 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 outer 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. Using finished elements ceilings, 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 floor, which is of secondary importance, its sound insulation is given Special attention. 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 insulation 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 on glue; 9 - sound-absorbing floor covering; 10 - logs with a section of 40x60 mm; 11 - gypsum boards with a thickness of 12 - 18 mm or chipboard with a thickness of 10 ... 16 mm; 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. various forms 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 stronger 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 studies of positive results, unfortunately, did not give. 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 outer wall, flat roof, ceilings of the attic (technical) floor or attic with sloping walls with a good roof are not needed. Protecting the same wood interfloor overlap 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 norms fire protection. 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 floor must have at least fire-retarding properties (the duration of fire resistance is at least 30 minutes per experimental conditions). For the manufacture of wooden structures, it is allowed to use solid wood and other wood materials regular size 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 floors made of wooden panels with fireproof insulation 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 11 × 24 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. 14. .

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 one side only.
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 finishing works. Therefore, we will talk about them in the next article.

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WOODEN FLOORINGS

Depending on the type of house, you should also choose a specific type of flooring. For example, in one-story houses with floors on the ground, only attic floors are arranged. In houses with a second floor or an attic, as well as in the presence of a basement, interfloor floors are arranged that carry a higher payload. IN garden houses for socle and attic floors, wooden beams and decking are often used. This type of flooring is sometimes used in the construction of small one-story residential buildings. In more capital houses, floors are made of prefabricated or monolithic reinforced concrete. The loads on the floors of residential buildings are made up of the calculated live load, that is, from the mass of furniture, equipment, people in the room, etc. and calculated constant. In this case, special attention should be paid to the loads from the installed plumbing equipment (boilers, bathtubs, etc.), the load for which is considered separately. The calculated constant load is understood as the own weight of the structure, and it depends on the type of ceiling, insulation, etc. For attic floors, 1050 N / m 2 is usually taken as the calculated live load, and 2100 N / m 2 for the basement floor.

attractiveness hardwood floor in that it is distinguished by the simplicity of the device, has good thermal insulation characteristics.

Installation of floor beams. The basis of any wooden floor is beams supported by load-bearing walls (Fig. 1). In this case, the beams must meet the requirements for them in terms of bearing capacity. Beams are made of round timber, processed into four edges, timber or boards 60-80 mm thick and installed on the edge. It is allowed to install paired boards with a thickness of 50 mm, which are “sewn” together with nails or metal staples. For large spans, the middle part of the beams is supported by internal walls, which reduce the likelihood of deflection.

Figure 1.: A - with a blind embedment in the outer walls; B - with open embedding in external walls; B - the same, into the inner walls; 1 - wooden beam; 2 - insulation with roofing paper on mastic; 3 - anchor; 4 - overlay; 5 - grouting

The beams are laid in a “lighthouse” way - first, the outer beams are installed, and then the intermediate ones. The correct position of the outer beams is verified 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. Do not trim the ends of the beams or place random chips under them.

In log or block walls, floor beams are cut into the upper crowns, and in frame walls they are installed on horizontal strapping and nailed. In stone walls, wooden beams are embedded with ends cut at an angle of 60-80 ° and their ends (with the exception of the ends) are tarred or upholstered with roofing paper. With a brick wall thickness of up to 2 bricks, the gaps between the ends of the beams and the brick wall are filled with cement mortar. Sometimes, instead, the ends of the beams are insulated 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 will protect the ends of the beams from moisture condensation. 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. Options for supporting the ends of floor beams are shown in fig. 2. Permissible sections of floor beams, depending on the length of the span, are presented in Table. 1.

Figure 2.: 1 - beam; 2 - overlap shield; 3 - hole with a diameter of 6 mm; 4 - metal anchor; 5 - nails; 6 - two layers of roofing felt (roofing material); 7 - filing the ceiling; A - embedding with a metal anchor

Table 1. Permissible values of beams of interfloor and attic floors, depending on the span at a load of 400 kg per 1 m 2

Span, m	Distance between beams, m	Log diameter, cm	Cross section of bars, cm

Beams and crossbars in the area of chimneys should be located at a distance of at least 38 cm from the smoke. This distance is sometimes reduced to 25 cm, but at the same time, a heat-insulating gasket made of asbestos sheet is installed between the wooden structures and the brickwork of the chimney. It is allowed to use felt impregnated with clay instead of asbestos gasket.

A simple beam ceiling is suitable for non-residential premises, since the sound-absorbing and heat-insulating properties of such a floor are rather low. The essence of the overlap is that between the individual beams a flooring is sewn from boards, which serves as the floor of the attic. The distance between the beams usually lies in the range of 80-90 cm. For large spans, additional racks are installed under the beams (Fig. 3).

Figure 3.: 1 - run; 2 - pillow; 3 - bolt; 4 - spike; 5 - struts; 6 - pillar

Overlapping from bars or logs of short stacks is arranged on small (up to 4 m) spans (Fig. 4). To do this, nests 8-15 cm wide are left in the walls, into which bars of the same section are inserted and tightly fitted to each other. Between themselves, the bars are fastened with long nails, which are hammered from the sides. When selecting bars, you should ensure that their sides fit snugly against each other without cracks and gaps. On fig. 5 shows the design of the overlap on the logs. The ceiling can be hemmed with one of the types of sheet materials, which are produced in a large assortment by modern industry.

Figure 4.: 1 - vapor barrier; 2 - thermal insulation; 3 - running board; 4 - facing beams; 5 - filing the ceiling; 6 - reel facing

Figure 5.: 1 - vapor barrier (roofing paper, grease); 2 - thermal insulation; 3 - reel; 4 - running board; 5 - filing the ceiling; 6 - beam; 7 - lag

Overlapping with backfill suit for residential buildings. This type of ceiling more fully meets the soundproof and heat-saving requirements (Fig. 6). They begin to do it with the laying of beams, the space between which is filled with rolling in the form of a continuous flooring of boards or shields. A layer of roofing paper or glassine is laid along the reel, along which heat-insulating material is laid. As a heat-insulating material, mineral wool, granular slag, perlite, expanded clay or another type of insulation can be used, the properties that we have already considered. The false ceiling is made of fibreboard or chipboard, finishing board or plasterboard.

www.baurum.ru

Fastening a beam to a concrete and brick wall

Drilling a brick should be done carefully, strictly at a right angle, without “loosening” the drill, so as not to split the brick. A split can cause brick shedding. if a brick gets into the cavity, you will have to use an anchor-type dowel, which, when wrapped into a wall, forms a knot, or an expansion dowel. Tighten the dowel carefully. Mechanical anchors for fastening wooden beams to brick walls are much better than self-tapping screws and nails, both technologically and in terms of fastening strength.

For concrete, you need a drill with a perforator function and strong plastic dowels for self-tapping screws, sometimes before driving a plastic dowel into the wall, it is additionally lubricated with glue.

Fastening a beam to a wooden wall

Apply perforated fasteners of the angle type or flat. Fasteners vary in size, metal thickness and coating. Nails, screws and screws are used. For large nails, pre-drill holes, especially when working with dried wood.

Fastening to the wall of aerated concrete and drywall

Gas blocks are soft material, full-length threaded screws are suitable for them, but it is better to use anchors, mechanical or chemical. In order to qualitatively install an anchor with bending ribs or a wedge-shaped one, a hole with a diameter slightly larger than the anchor is pre-drilled. One of the types of anchors is great for hollow blocks and blocks made of cellular concrete - foam blocks, gas blocks, etc. The main "details" of the anchor are a steel sleeve with ribs and a nut at the end. When the screw is screwed into the sleeve, the ribs bend and move apart, forming a "butterfly" that holds the anchor securely inside the material.

Chemical anchors hold even stronger, they are suitable for everyone wall materials from lightweight concrete and for drywall, and for any wall materials. The principle of operation is the ability of synthetic resins to penetrate deeply into the pores and adhere to the base. weak link fasteners to porous blocks and drywall are not fasteners, but the base material, especially under the action of a vertical load, and it is precisely these problems that chemical anchors help to solve. Insert a chemical anchor using a special gun. The adhesive mass is squeezed out under pressure into the drilled hole, and immediately inserted fastener- threaded stud or stem. Adhesive composition fills the pores of aerated concrete or other porous block, and after hardening forms a strong and reliable fastening. The pull-out force of a chemical anchor from a brick is more than 500 kg. The service life of chemical anchors is tens of years, they do not deform from temperature changes, they are inert to aggressive environments. The latter is very important when working with aerated concrete, which is aggressive to metals. All fasteners for aerated concrete must have an anti-corrosion coating.

For fastening the bar to aerated concrete or drywall, the anchor method of fastening is the most durable, although costly. It all depends on the density (grade) of aerated concrete and on the required load. To fasten the battens, it may be sufficient to use mechanical anchors - wedge-shaped or "spiral nails" type. The latter are convenient in that they are mounted in a wall of aerated concrete, hammering with an ordinary hammer. When hammering, the spiral nail is screwed into the block without disturbing its porous structure.

The dowel, which in its working position looks like the spokes of a half-open umbrella, bears the affectionate name of Molly and is great for attaching wooden blocks to drywall partitions in order to fix paintings, light shelves or lamps on them. Molly - a type of expansion anchor bolt having a sleeve with longitudinal slots, which, when the thread of the inserted screw is tightened to the stop, folds and turns into an umbrella. The bearing capacity is excellent, but this mount has drawbacks - it can be removed only by breaking out part of the partition. In addition, it is impossible to work with Molly in a cramped space.

Fastening timber in roof structures

Logs from a bar are attached lock connection and brackets, but such a docking is unacceptable for the roof, since the roof is operated in completely different conditions. All roof elements truss system) are installed according to the design and calculation, and they are fixed with special elements and bolt systems, sometimes they are additionally reinforced with brackets.

Mounting a bar on a suspension

In interiors, decor elements are sometimes used, for which it is required to fix the beam to the ceiling on a free suspension or to imitate such a suspension. Sometimes a beam suspension is needed for structural reasons. This type of fastening is carried out by means of a special suspension, designed for a certain load. A suspension system of this type may have the additional ability to adjust the height of the beam suspension.

The suspensions are attached to the ceiling with dowels, and the second part of the fastening is installed on the beam, then the elements are connected. Practice shows that such fasteners, contrary to expectations, can withstand considerable loads. But still, it’s better not to have a similar risk factor above your head, and for design, imitate a suspension, and fasten the beam securely into the wall. The suspension system in this case is installed to strengthen the mount, and for design purposes, “for beauty”.

stroyfora.ru

This article discusses the schemes of classical constructive solutions for support nodes of load-bearing metal beams of floors (coverings) on the brick walls of buildings. The use of these schemes in the design of beam ceilings will save the designer from a lot of routine calculations related to the layout of the support nodes of the beams, the selection of sections of individual elements (ensuring the operability of the nodes) and the calculation of their field connections.

The decision to choose one of the options proposed below for the structural design of the nodes supporting the beams on the walls is made based on the magnitude of the support reaction (support pressure at the end of the beam).

According to the requirements of current regulations, steel beams must be supported on load-bearing stone walls through steel or reinforced concrete distribution pads, the main function of which is to equalize the pressure under the ends of the beams and prevent local collapse of the masonry (local destruction of the masonry under the supporting sections of the beams from collapse).

Nodes No. 1, 2, 3, 4 provide articulated support of the beams directly on the brickwork of the walls through a layer of cement-sand mortar 15 mm thick. The support pressure under the end of the beam embedded in the wall is transmitted to the masonry through the support metal plates 20 mm thick, the dimensions of which are assigned in such a way that the average pressure under the plate (within the compression area) does not exceed the minimum admissible the value of the design resistance of the masonry, provided that the masonry is made of solid ceramic bricks of normal strength on a hard cement mortar.

If the value of the support pressure exceeds 100 kN (≈10 tons), then, in accordance with the requirements of SNiP ll-22-81 *, it is necessary to install a reinforced concrete distribution pad with a thickness of at least 100 mm, reinforced with two grids according to the calculation (supporting the carrier steel floor beams directly on the brickwork of the walls in this case is not allowed). In this case, the supporting nodes of the beams are performed tough- see Knots No. 4, 5.

Node No. 1 (articulated)
Brick wall thickness b=380 mm. The limiting value of the support reaction R=0.6 t.

Knot No. 2 (articulated)
Brick wall thickness b>380 mm. The limiting value of the support reaction R=0.7 - 3.0 t.

Knot No. 3 (articulated)
Brick wall thickness b>380 mm. The limiting value of the support reaction R=3.1 - 5.0 tons.

Knot No. 4 (articulated)
Brick wall thickness b>380 mm. The limiting value of the support reaction R=5.1 - 7.0 tons.

Node #5 (hard)
Brick wall thickness b>380 mm. The limiting value of the support reaction R=10.1 - 18.0 t.

Knot #6 (hard)
Brick wall thickness b>380 mm. The limiting value of the support reaction R=18.1 - 20.0 t.

probuild-info.ru

We close the beams in the wall

Scheme of supporting a wooden beam on a wall.

In construction, the stage of embedding beams into the wall is the most important and responsible. Floor structures must meet the high requirements of reliability and strength, since they are the guarantee of the safety of all those living in the house.

The first thing to do is to cut the end ends of the beams at an angle equal to 60 degrees.
Perform the processing of the end ends of the beams using an antiseptic composition. Another action characteristic of this stage is the resin treatment procedure.
Next, you need to wrap the ends of the beams with roofing paper and lay them in such a way that they do not reach the rear wall of the nest, by about 40 mm (+ - 10 mm).
After the beam is laid, its sides (side and top) are sealed with a mortar, which includes crushed stone as a component.

Supporting beams on brick walls: a - with embedment in the wall, b - with clamps, c - on the console, d - on pilasters. 1 - clamp, 2 - console, 3 - pilaster.

With the existing wall thickness equal to 2.5 bricks (this is approximately 640 mm) or more, the beams, or rather their ends, are not covered with mortar. For this, another termination option is more suitable.

Since the beam with its end ends rests on the walls (usually no more than 150 mm), it is clear that there is a free space between its end and the socket (rear) wall, approximately 100 mm.

This distance is suitable in order to respect the air gap and to complete the installation of thermal insulation. As for the nest, its bottom is to be leveled with concrete, then a bitumen layer and two roofing layers are applied.

The upper part of the nest and its side walls are covered with roofing felt.

Scheme of sealing the ceiling into the outer wall: 1 - wall; 2 - lining; 3 - embedded end of the beam; 4 - floor slab.

But for the back wall use tarred felt. This layer of felt is pressed against an antiseptic board. Its thickness usually corresponds to 25 mm.

Please note that the end of the beam must be laid in such a way that the space obtained between it and the board is approximately 40 mm.

If the walls of your house are less than the above-mentioned size, for example, two bricks, then the following method will suit you.

Just as in the first case, the back wall of the nest is covered with tarred felt in two layers.
Then a box with three walls is made, its surface is tarred, and it is installed in the nest, the felt laid earlier is pressed against it.
If, however, the beams are sealed during the construction of the attic floor, and the walls at the same time correspond to a thickness of two bricks, then special attention must be paid to the nests, or rather their protection. As in the above example, it is necessary to make a box with three walls, tar its surface and upholster it with felt.
Beams located near the chimney pipes are located at a distance of not less than 400 mm to its inner surface.

Scheme of embedding a wooden floor beam in brick wall: 1 - wooden beam; 2 - the end of the beam, smeared with resin and wrapped with roofing felt;

3 - waterproofing; 4 - brick wall; 5 - air gap between the wall and the beveled end of the beam.

Of course, it also happens that the beam cannot be located more than far distance from the chimney. Under such circumstances, the beam is cut into the crossbar structure.

And the bolt itself is already cut into two beams, as a result of which they are weakened. Reducing the weakening is achieved by laying the beams with a thicker end in relation to the chimney.

During the construction of brick, stone and other similar structures, it is necessary to observe the condition under which there will be a gap of at least 50 mm between the wall and the outer beams. Its termination is carried out using a rail. Do not forget that the rail and beam are separated from each other with a layer of roofing felt or a layer of roofing felt.

Based on site materials: http://1pokirpichy.ru

fix-builder.ru

Overlappings are structures that perform both load-bearing and enclosing functions. In civil buildings with walls made of small-sized elements, beam or slab floors can be used as a load-bearing part. The composition of the enclosing part is determined by the design of the bearing honor and the purpose of the floor.

Overlappings on wooden beams used in buildings up to four floors high. Beams are most often made of rectangular cross-section from solid or glued wood. To support the inter-beam filling, cranial bars are nailed to the beams on one or both sides. The nomenclature of beams with cranial bars is shown in Figure 3.1, b. The cranial bars with a section of 40x50 mm are nailed to the beams with nails ø-4.5 mm, ℓ=125 mm in increments of 300 mm.

The support of the beams on the walls must be at least 180 mm. The ends of the beams in a section of 50-75 cm from the end are antiseptic, and when leaning on the outer walls or the inner walls of damp rooms, they are coated with tar or bitumen and wrapped with roofing paper. The ends of the beams are left open to remove moisture from the beams during the operation of the ceiling. When beams are supported on internal and external layered walls with a bearing layer thickness of less than 510 mm, a closed seal is performed (Fig. 3.1, e and f). The fastening of beams in the outer walls is carried out with the help of anchors embedded in the masonry of the wall and connected to the beam with nails. On the inner walls, two opposite beams are connected with metal plates.

Between the beams along the cranial bars, a reel is laid from wooden shields up to 2 m long (Fig. 3.1, c, d), slabs or gypsum boards. Clay grease 20-30 mm thick is arranged over the roll-up shields or a layer is laid roll waterproofing. In interfloor ceilings, a layer of sound insulation made of slag or calcined sand 50-60 mm thick is laid on clay lubricant or roofing, and in attic floors - a layer of thermal insulation made of the same materials with a thickness of 200-260 mm. Can also be used as soundproofing and insulation mineral wool boards and other non-combustible thermal insulation materials. The floor in such ceilings is laid along the logs or directly along the beams with a beam spacing of 0.6 m.

Floor structures on wooden beams are shown in Figures 3.2 and 3.3.

Figure 3.1, a shows a fragment of the floor plan along wooden beams with the rolling of their wooden shields.

Figure 3.1. Ceilings on wooden beams with cranial bars

a - a fragment of the floor plan; b - nomenclature of wooden beams; c - roll-up boards with support through overhead strips; d - the same with continuous support on the cranial bars; d - beam support on the outer wall; e - support of beams on the inner wall of rooms with normal humidity;

1 - bearing brick layer; 2 - antiseptic ends of the beams (including the end); 3 - wrap ends with roofing paper (excluding ends); 4 - blind embedment with cement-sand mortar; 5 - steel L-shaped anchor 50x5 mm; 6 - two layers of roofing; 7 - an anchor made of strip steel

Rice. 3.2. Floor structures on wooden beams with cranial bars

a - interfloor with a roll of slabs; b - interfloor with a roll of wooden shields; in - attic with a roll-up of shields; g - interfloor with a false ceiling;

1 - wooden beam; 2 - reel from slabs; 3 - reel from wooden shields;

4 - clay lubricant; 5 - only; 6 - backfill made of glass; 7 - effective insulation;

8 - a package of roofing; 9 - log; 10 - clean floor boards; 11 - running boards

Rice. 3.3. Laminated timber beam slabs with suspended ceilings

1 - glued wooden beam; 2 - spring clip; 3 - transverse filing 25x50 mm; 4 - gypsum boards; 5 - mineral wool boards; 6 - particle boards; 7 - felt pad; 8 - log 40x60 mm; 9 - parquet boards

Reinforced concrete beams floors are laid in increments of 0.6 - 1.1 m (Fig. 3.4). The depth of embedding the beam into a stone wall is 180-200 mm. The ends of the beams are insulated from the outside (Fig. 3.5). Liners of inter-beam filling are laid along the beams (Fig. 3.6). Options for the device of interfloor and attic floors according to reinforced concrete beams shown in fig. 3.7.

Overlappings By metal beams have a similar design solution (Fig. 3.8).

When supporting beams on walls made of gas silicate, cellular concrete or expanded clay concrete blocks, the installation of monolithic or precast-monolithic (Fig. 1.3) reinforced belts should be provided.

Rice. 3.4. Fragment of the floor plan for reinforced concrete beams

Rice. 3.5. Joints of precast concrete beams with walls

a - leaning on the outer wall; b - leaning on the inner wall; c - adjoining a self-supporting wall

1 - reinforced concrete beam; 2 - steel anchor; 3 - insulation; 4 - cement-sand mortar

Rice. 3.6. Inserts of interbeam filling

a - gypsum or gypsum concrete; b - lightweight concrete double-hollow; c - reinforced concrete top slab; g - expanded clay concrete insert of a solid section; e - reinforced concrete trough section; e - reinforced concrete vaulted

Rice. 3.7. Ceilings on reinforced concrete beams

a, b - interfloor; c - attic

Rice. 3.8. Interfloor ceiling on steel beams

Overlaps in the form hollow core decking shown in Figure 3.9. The most commonly used slabs with round voids 220 mm thick are used for spans of 2.4-7.2 m (with a gradation of 0.3 m), 300 and 360 mm for spans of 9 and 12 m, respectively. The slabs work only in the longitudinal direction, and, therefore, they must rest on load-bearing walls made of bricks or ceramic stones with short sides of at least 90 mm. Leaning on walls made of cellular concrete - by 120-150 mm. To strengthen the supporting sections, it is planned to reduce the size of the voids from one end, and from the other, resting on the outer wall, a plug with concrete inserts. The joint work of the floors is ensured by the connection of the panels with steel welded ties.

IN Lately slabs with vertical voids, produced by formless molding, have been widely used (Fig. 3.9).

In buildings with walls made of small-sized elements, it is also possible to use cellular concrete floor slabs. The design of such an overlap is shown in Figure 3.10.

Figure 3.11 shows examples of design solutions sexes on multi-hollow flooring.

In buildings without basements, the floors of the first floor can be made along logs or along the ground (Fig. 3.12).

IN last years in the construction of low-rise buildings are increasingly used prefabricated monolithic beam(frequently ribbed) floor structures (Fig. 3.13 - 3.15). Such floors are used for spans up to 7.8 m.

Rice. 3.9. Hollow core slabs floors

a - main dimensions; b - options for adjoining the slab to the wall;

d) - a fragment of the floor plan

Rice. 3.10. Aerated concrete floor slabs

a - the main dimensions of the plates; b - support of cellular concrete slabs on the wall; in - pairing of plates among themselves; d - floor plan

Figure 3.11. Floors on floor slabs

Figure 3.12. Floors of the first floor of buildings without basements (waterproofing is not shown conventionally)

Rice. 3.13. Prefabricated-monolithic floors (section across the beams)

Rice. 3.14. Prefabricated monolithic ceilings (supporting beams on the wall)

Fig.3.15. Fragment of the plan of the prefabricated monolithic floor

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

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

Width span, m	Distance between beams, m
	0,5				1

	1,5 (150)	2,5 (250)	3,5 (350)	4,5 (450)	1,5 (150)	2,5 (250)	3,5 (350)
2,0	5 x 8	5 x 10	5 x 11	5 x 12 (10 x 10)	10 x 10	10 x 10	10 x 11
2,5	5 x 10	5 x 12 (10 x 10)	5 x 13 (10 x 11)	5 x 15 (10 x 12)	10 x 10	10 x 12	10 x 13
3,0	5 x 12 (10 x 10)	5 x 14 (10 x 11)	5 x 16 (10 x 13)	5 x 18 (10 x 14)	10 x 12	10 x 14	10 x 15
3,5	5 x 14 (10 x 11)	5 x 16 (10 x 13)	5 x 18 (10 x 15)	10 x 16	10 x 14	10 x 16	10 x 18 (15 x 16)
4,0	5 x 16 (10 x 13)	5 x 18 (10 x 15)	10 x 17 (15 x 15)	10 x 18 (15 x 16)	10 x 16	10 x 19	10 x 21 (15 x 19)
4,5	5 x 18 (10 x 14)	10 x 17 (15 x 15)	10 x 19 (15 x 17)	10 x 20 (15 x 18)	10 x 18	10 x 21	10 x 23 (15 x 21)
5,0	10 x 16	10 x 19 (15 x 16)	10 x 21 (15 x 18)	10 x 23 (15 x 20)	10 x 20	10 x 23	10 x 26 (15 x 23)

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 directly during the laying process ( 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 with 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.

Roll forward

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, instead of boards for rolling, you can use fiberboard, gypsum slag and other lightweight concrete slabs, 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

Material	Volume weight, kg/m³	Backfill thickness (mm) at outdoor air temperature, °C
Material	Volume weight, kg/m³	-15	-20	-25
sawdust	250	50	50	60
Wood shavings	300	60	70	80
Agloporite	800	100	120	140
Boiler slag	1000	130	160	190

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 log and a clean floor

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, the wall thickness of the chimney increases to 1 brick, that is, up to 25 cm. But even in this case, the floor beams should not touch the masonry of the pipe and be at least 35 cm from the hot surface. This distance can be reduced to 30 cm by laying between the cutting and the beam of felt or asbestos cardboard 3 mm thick 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

An economical floor is considered to be a floor consisting of wooden panels 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.

Rice. 8. .

Methods for calculating wooden floors

Deflection limit under standard load

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.

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.
To make a ceiling with open (that is, not sheathed from below) wooden beams, which would provide reliable noise protection, is hardly possible today. New scientific studies of positive results, unfortunately, did not give. So the question of the perfection of noise-protecting structures is waiting to be decided.

Weather protection

Wooden structures of the outer wall, flat roof, ceiling of the attic (technical) floor or attic with sloping walls do not need special protection from climatic influences with a good roof. 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 floor 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 above, we can conclude that there are still enough questions regarding the reliability of sound insulation and fire safety of ceilings, and in the coming years they will have to be solved by the joint efforts of scientists, designers, manufacturers of building materials, designers and builders.

Increasing the bearing capacity of floor beams

Rice. 14. .

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.

Part 7. Overlappings. (section 6, item 2.)

6.2.8. Supporting girders and floor beams

6.2.8.1. When supporting purlins and floor beams on masonry the support pads under the girders and beams must be of sufficient size to accommodate the transmitted load. The length of the platform for supporting girders on masonry or concrete must be at least 89 mm, floor beams - at least 38 mm. The length of the support platform for girders and beams, nailed at the ends to the strapping beams, on wooden elements wall frame should be at least 38 mm.

6.2.8.2. The ends of the purlins and beams of the lower floor (ceiling above the basement) must either be embedded in a concrete or stone foundation wall in accordance with Figure.1. or attached to the lower strapping beams installed on a support board laid on the foundation wall (see Fig. 2.).

The second option is provided in cases where the calculation of the wind load leads to the conclusion about the need to anchor the frame of the house on the foundation. There are other options for fixing the elements of the frame of the lower floor on the foundation walls (see Fig. 3.)

6.2.8.3. Elements wooden frame floors, based on concrete or masonry, it is recommended to be made from lumber treated with antiseptics. It is allowed to use lumber that has not been treated with antiseptics, subject to the conditions indicated in Figure 2. , but the requirements for sealing the ends of all runs and beams, the bottom of which is located above ground level. In cases where bottom of girders and beams from lumber not treated with antiseptics is at or below the ground level, at their ends embedded in masonry or concrete, unfilled air gaps with a width of at least 10 mm must be left, and the supporting surface of beams and girders must be separated from concrete or masonry waterproofing material(Fig. 2b). In all cases of use of non-preserved lumber, the outer surfaces of concrete or masonry walls must be insulated from moisture penetration.
6.2.8.4. The bottom support board with a cross section of at least 38x88 mm must be laid on the foundation wall in level, on a layer of mortar or on a sealing gasket made of sealing material. support board must be attached to the foundation wall with anchor steel bolts with a diameter of at least 12 mm according to [GOST 1759.0 Bolts, screws, studs and nuts. Specifications.].
Anchor bolts should be placed with a step determined by calculation, but not more than 2.4 m, fixed on bottom harness frame with nuts and washers and embedded in the foundation to a depth of at least 100 mm(see fig. 2.).
6.2.8.5. beams And floor joists lean on the upper strapping of the frame bearing walls. Strapping beams are nailed to their ends so that the outer edge of the strapping beam is in the same plane with the outer side of the wall frame (see Fig. 4.).

6.2.8.6. Supporting floor beams on girders can be carried out either along the top of the runs (Fig. 5.), or by attaching them to the side faces of the runs. The first of these options is used mainly in the ceiling above the basement, when the ends of the runs are embedded in a stone or concrete foundation wall. In this case, the joints of the floor beams are overlapped. For interfloor and attic floors, the second option for supporting beams is preferable.

6.2.8.7. When attaching beams to the side surface of wooden girders, the support is carried out either on metal corner plates or on wooden support bars nailed to the side surface of the girders (see Fig. 6.).

6.2.8.8. When attaching wooden beams to steel girders, they must rest on the lower flange of the purlin or on a backing bar with a section of at least 38x38 mm, attached to the wall of the purlin with bolts with a diameter of 6 mm in increments of 600 mm (Fig. 7.).

beams must be connected above the purlin using a connecting bar with a section of at least 38x38 mm and a length of at least 600 mm to support the subfloor above the purlin. A gap of at least 10 mm must be left between this bar and the upper surface of the run (in case of shrinkage of wooden beams).
6.2.8.9. floor beams, supported on steel girders, should be kept from twisting and warping by driving at each end of the beam with nails at an angle, bent over the flange of the purlin, or by a continuous strapping of boards along the bottom of the beams at the supports, or by creating a system of vertical cross-braces between the beams in accordance with 6.2 .9.

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Construction of wooden frame houses:
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Overlappings, as you know, can be slab, and can be beam. The first option, of course, is very reliable, but it requires considerable investments, including for hiring lifting equipment.

When building a one- or two-story private house, including a brick one, such strength is not required at all. In addition, this is an extra load on the walls and foundation, therefore, in low-rise construction, beam ceilings are mainly arranged.

For those who build a house with their own hands, a logical question arises: “How is a wooden beam supported on a brick wall?”. To understand this topic, we will use the video in this article.

Wooden beams and requirements for them

In principle, beam ceilings can also be different: reinforced concrete, metal, or wood. The first two options are not inferior in technical characteristics to slab floors, but they are quite difficult to perform, and therefore they are practically not used in private construction. But wooden beams are a completely different matter!

So:

Despite the apparent simplicity, there are also a lot of nuances that must be observed here. First of all, you should choose the right lumber. Most often, hardwood of coniferous species is used for this purpose: larch, pine, spruce, cedar. The price here does not matter - it's just that softwood beams work best for bending.

There are, of course, hardwood proponents who claim that aspen and birch do the job just fine. Only now building codes recommend that in general all load-bearing wooden structures - and not just floor beams, be made from coniferous lumber. hard rocks hardwood, suitable only for connecting parts (pins, dowels, etc.).
The beam for overlapping can, and even preferably, be used planed, not glued. It must be well dried and treated before installation with a fire-retardant compound. In heated buildings, solid beams must be installed without interfering with walls and partitions, and the floor structure, as such, must guarantee good ventilation.

Deaf (monolithic) embedding of beams into walls is not allowed - they are laid in nests, and always on shock-absorbing hardwood pads. The ends of beams mounted with metal fasteners must be protected with a moisture-proof layer, since when condensation forms, metal corrosion can also lead to wood corrosion.

But before proceeding to installation work, load-bearing elements overlap must be calculated. Therefore, further your attention will be offered instructions for selecting the section of beams and determining the step of their installation.

Dimensions of beams and methods of their installation

So, you need to determine how many beams you need to install, and what size they should be in cross section. First of all, it is necessary to measure the span of the floor, and, having determined the depth of their laying in the walls, calculate the operational loads.

So:

The length of the beams depends on the option of their fastening.. If the ends are laid in the wall, then their length can be obtained by adding the span and twice the depth of the beam (by two ends). In block and brick houses, the depth of nests for laying beams is at least 10-15 cm, which depends on their size.

If the beams will be attached to the walls using metal clamps or consoles, then their length corresponds to the distance between parallel walls. A lot depends on where exactly the ceiling is being built: above the basement, between floors, or in the attic. Sometimes, when arranging attic floors, beams are released outside, outside the walls, mounting rafter legs to them.
This is one of the ways to form a roof overhang.. In another version, the beams of the non-attic floor can be mounted directly to the Mauerlat beam - which we see in the photo below. Naturally, the length of the beams with the same span will be different in such situations, and when calculating the constituent elements of the floor, all these nuances must be taken into account.

Note! The maximum length of beams from a bar or edged board, is 6m. If you need to cover a larger span, it is better to give preference to metal I-beams, or instead of beams you will have to use wooden trusses. But in general, for a wooden floor, six meters is too much - the most best option- span within 3-4m.

Loads

The load that the ceiling perceives consists of two components: the own weight of the structure, and the operational load (people, furniture, equipment). It can be calculated in a simplified way.

For example, the own weight of an attic floor with light mineral wool insulation is traditionally 50 kg/m2.

So:

According to the norms, the operational load for a non-residential attic, in which things are not stored, is no more than 70 kg / m2. It is multiplied by a safety factor, taken as 1.3, and added to the constant load. After all the manipulations, the result is 130 kg / m2. This figure needs to be rounded up - that is, up to 150 kg / m2.

But for attic insulation, heavier material can also be used, for example, expanded clay - and naturally, its weight must also be taken into account. The picture changes dramatically if the attic turns into residential attic. In this case, the normative operational load is no longer 70, but 150 kg/m2.

Here you need to add the weight of the one mounted in the lower room false ceiling, and the engineering communications laid into it - and this is at least 15-25 kg. Both the weight of the flooring and the weight of the zoning partitions should be taken into account, if any will be erected in the upper room.

All additional loads must be added to the standard load, but the own weight of the floor and the safety factor are the same. The calculation of loads is carried out in a similar way, according to the same formula, which was mentioned above.

The ideal option is if the basement and interfloor ceilings are designed for 400 kg / m2 - then it can easily withstand massive furniture, a piano, and an influx of guests.

Sections

After you have calculated the length of the beams and the loads they perceive, you can proceed to the selection of the section. It is most convenient to use a rectangular beam for this purpose - while the aspect ratio of 1.35: 1 is considered optimal.

Since a slab insulation is laid in the floor structure, you need to navigate by its thickness, plus a small ventilation gap.

The step between the beams, again, should be correlated with the size of the heat-insulating plates, only now with their width. But to be more precise, it is rather the opposite, the insulation is selected for the floor structure. The distance between the beams and their cross section can be selected from such a table, which we give below.

This is a simplified selection method, so do not forget that insurance never gets in the way. Therefore, it is always better to increase the margin, and round up all values.

The step between the beams is determined in such a way that the extreme beam is not close to the walls or Mauerlat, and there is a distance of at least 20 cm between them.

Installation nuances

We have already said that the installation of beams can be done in two ways: by laying in nests specially provided in the masonry, and by fastening with clamps or other metal devices.

So:

Let's consider the first way. To do this, the ends of the ceiling beam must be cut at an angle of 60 degrees, and processed bituminous mastic or any other hydrophobic composition, and then also wrap them roll material: glassine or roofing felt.

Before installing the beam, near the rear wall of the mounting socket, a piece of foam or other insulation is laid - there must be a wooden gasket under the beam. The ceiling beam is laid in nests so that between its end and back wall nest, there were still a few millimeters of clearance.

A very convenient method of mounting floor beams on a metal console, and the diagram above shows its support unit. And yet, please note that for reliability, crossbars are mounted between the beams, connected to them by means of metal corners.

It turns out a kind of frame, which is hemmed from below with a board or drywall. Then, from the side of the upper room, the “filling” is laid in it: vapor barrier and insulation, after which rigid sheet material is mounted on top of the beams: OSP boards, DSP, plywood, chipboard. Further equipped flooring top floor - but that's a completely different topic.