How to block a 6 meter span. Features, types and calculation of wooden floor beams. Cross-section and step of timber floor beams

Arbolit - lightweight concrete with organic aggregate wood chips (not sawdust or shavings). The material does not overload the foundation, retains heat well, and is suitable for residential and industrial buildings up to three floors high. It is produced in the form of panels, slabs, wall and partition blocks. It is relatively easy to build a house from your own hands, even in the absence of experience due to convenient size and light weight.

An ideal geometry that assumes deviations from standard sizes up to 1 mm, have only products manufactured at large enterprises using special equipment, they are relatively expensive. More often, for private construction, stones produced by hand are bought. They are cheaper, but size deviations can reach 3 mm. It is necessary to compensate for this disadvantage by making seams with a thickness of 8 to 12 mm.

To avoid cold bridges in the walls, seams can be made using thermal break technology. To do this, before applying the solution to a number of stones, a rail 4-5 cm wide or a tape - jute or foamed polypropylene - is placed. Then applied on both sides of the tape or strip strip masonry mixture. An empty space remains between the strips, which, after the installation of the next row, is filled with air. The rail, after completing the application of the mass, is removed, the tape can be left. A thermal break is needed for joints with a thickness of 8 mm or more. If the stones have minimal deviations in size from the standard, then the mixture or glue is distributed in a thin layer (up to 5 mm). Additional measures of insulation of the seams are not needed.

Preparation of masonry mortar

The choice of a suitable variety is made on the basis of the quality of the geometry of the blocks. If you need seams from 8 mm, then you need to minimize heat loss through them. Therefore, various insulating components are added to their composition.

For walls made of arbolite blocks, the following types are used:

1. Cement-sand. You can make your own or buy ready-made dry mix. The optimal proportions are 3 hours of sand for 1 part of cement. This option is valid only for stones with ideal geometry. Wide seams inevitably become cold bridges.

2. Perlite. Refers to warm, has a much better indicator of preventing heat loss. You can buy ready-made mixtures of perlite sand with cement, but it is cheaper to make them on your own. For preparation, you will need 1 part of cement, 2 parts of ordinary sand and 3 parts of expanded perlite. It is better to prepare the mass in a concrete mixer: first, perlite is poured, then water is poured. Perlite immediately absorbs all the moisture (takes the form of a dry powder), when mixed with cement and sand, it begins to give it away, so you can not add water before pouring the rest of the components.

3. Masonry warm mass with microchips. For its preparation, a ready-made sand-cement mixture of a grade not lower than M-200 and processed small chips are used. In fact, it turns out a monolithic wood concrete wall. Microchips can be purchased from block manufacturers. Consumption: 1 bag (180 l) per 2 m3 of solution. Unlike perlite, it does not shrink. Recipe: 1 part of cement, 1 hour of sand, 2 hours of microchips, plasticizer - professional or simple liquid soap.

4. Cement-sand with sawdust (sawdust concrete). Recipe: 1 bucket of cement, 2 buckets of sand, 2 buckets of sawdust, a solution of 150 g of calcium chloride, 15-20 g of liquid soap.

5. Adhesive dry mixes (mounting adhesives). The permissible layer thickness for them is 2-5 mm. Ready masses are suitable for gluing stones with deviations in size up to 1 mm.

6. Polyurethane foam adhesive-foam for products made of cellular concrete with height deviations up to 1 mm. Some brands of this product are only suitable for internal walls and partitions. Consumption 1 cylinder 850 ml per 10 m2.

When choosing, it is taken into account that the arbolite almost does not absorb moisture contained in the air, but draws it out of the solution during installation, so the blocks must be abundantly moistened before installation. When using glue, there is no such problem.

Step by step instructions for laying the first row

1. Mark according to the diagram the location of doorways and joints between external and internal walls. For this purpose, use arbolite stones (without mortar).
2. Prepare mass. Apply it to the end in contact with the next product and the top surface.
3. At each wall junction, install two blocks at right angles to each other. For the first row, stones with minimal size deviations are selected. Stretch the cords between the corners.
4. Level to check the position of the elements.
5. Lay out the first row according to the scheme. Arbolite is cut with a grinder or a circular saw, the level is checked for accuracy.
6. Continue the installation of subsequent rows no earlier than one day after the completion of the first. If it is necessary to speed up the process, then hardeners are added to the solution.

Laying guide for the remaining rows of block walls

1. All subsequent rows begin to be placed from the corners.
2. The laying of wood concrete is carried out, like brick, in a checkerboard pattern - the vertical seams between the blocks of different rows should not coincide, the offset is done by half a stone.
3. Every two rows, the mixture in the seams is leveled on the surface of the stones.
4. In every third to fifth row, a reinforcing mesh is laid over the solution.
5. No more than three rows are laid out per day.
6. For reinforcement, an armored belt is made. This is a monolithic reinforced concrete strip, on which floor slabs and rafter system. Mounted from special U-shaped blocks with a notch. Reinforcement is placed in the gutter and concrete is poured.
7. Lintels above the openings are reinforced with ready-made reinforced concrete or metal beams. On each side, the jumper must rest on the wall by at least 20 cm.

Errors can be associated with the wrong choice of seam thickness and glue, the result is cold bridges.

Widely used in construction low-rise buildings. The laying of wood concrete blocks is in many ways similar to the laying of ordinary bricks, but it has a number of features.

Solutions used for laying wood concrete blocks

The most common mortar used for laying wood concrete blocks is a cement-sand mixture in a ratio of 1: 3. Preparing and using such a solution is quite simple; also with its help you can easily correct the difference in the thickness of individual blocks. The fact is that some manufacturers allow significant deviations from the established overall dimensions of products. To smooth out this drawback, it is necessary to make the masonry joint thicker (8-15 mm): the sand-cement mortar allows this to be done. All this applies to pluses, and the minus is that a thick masonry seam has a higher thermal conductivity than wood concrete. And this significantly worsens the heat-saving properties of the entire structure. That is, by laying blocks on a cement-sand mortar, we get a huge number of cold bridges in the form of seams between them. To make the building warm, cold bridges must be eliminated without fail.

For laying wood concrete, a solution is also used, which includes cement, perlite (a rock of volcanic origin) and sand in a ratio of 1: 3: 2. Perlite is a good thermal insulator, which can significantly reduce the thermal conductivity of the masonry joint. This eliminates the need to eliminate cold bridges. In addition, the presence of perlite in the mixture makes it more plastic.

Important! So that perlite does not lose its properties, do not be too zealous when mixing the mortar in a concrete mixer (otherwise, perlite may “curl” into granules).

The use of ready-made adhesives makes it possible to make the masonry joint very thin (up to several millimeters), so cold bridges do not form in such joints. It is possible to use adhesive compositions only when laying blocks that have minimal deviations from the declared geometric dimensions.

First row of masonry

The correct geometry of the entire structure largely depends on the correct marking and installation of the first row of masonry. In order to make markings, we determine the places of doorways and the junctions of the inner walls to the outer ones. It is best to do this with the help of the arbolite blocks themselves (naturally, laid out without using a solution - dry). As a result, you will be able to mark the row with the greatest accuracy and determine the location of incomplete (sawn) blocks.

We start laying by installing two whole blocks (forming a right angle) from each corner, which will serve as beacons. Dry blocks before laying are wetted with water so that they do not take liquid from the solution (arbolite has a high hygroscopicity). We apply the mixture on the base and on the end part of one block. The width of the seam depends on the size of the building material. All installed beacons must be on the same horizontal line: we achieve this with the help of a laser level.

Advice! For the first row, use the most even and matching products.

Next, we install the remaining blocks of the first row, which are the basis for the entire masonry. In order for them to be set correctly, we stretch the building cord between the corner blocks. We apply the mixture not only on the surface of the base, but also on the side of the block, which will be in contact with the first.

Important! We check each row of masonry with a level.

Naturally, when building walls, you will need blocks of incomplete size (additional ones), which are easy to make with a grinder or an electric saw (arbolite is easily sawn).

Important! Additional blocks are coated on three sides with a solution and placed in gaps.

We resume laying the subsequent rows only after a day (if hardeners are added to the mixture, then it is possible earlier).

Second and subsequent rows of masonry

The second row (like all subsequent ones) must also start from the corners. At the same time, it is important that the masonry is staggered (as in the construction of brick walls). That is, we shift the vertical seams relative to each other by half the length of the block, thereby ensuring the dressing of the rows with each other. We observe the same method of overlapping at the junctions of the inner walls with the outer ones. The structure from this only becomes stronger.

Advice! Perform no more than two or three rows per day (this applies to all rows except the first). Then it is recommended to take a break for a day.

After the formation of the first 4 rows, it is necessary to mark up window openings by pre-laying blocks around the entire perimeter without the use of mortar. This will allow you to determine in advance the places where the cut blocks will be used so that the vertical seams of the masonry do not match, and a checkerboard pattern is observed.

We make masonry from arbolite blocks

In order to lay arbolite blocks:

• apply a layer of the mixture;
• install a block pre-moistened with water;
• we press to the previous one (with effort);
• we correct the position of the block relative to other "brothers" using a special hammer with a rubber nozzle;
• check the level;
• remove excess mixture with a trowel.

• work can be carried out only on condition that the air temperature is not lower than + 6˚С;
• it is recommended to make the solution quite thick, since if the consistency is liquid, then the building material will “shrink” significantly;
• regardless of the consistency of the solution, every two rows it is necessary to perform cutting of the seams, which consists in evenly distributing the mixture along the seams;
• if the adhesion of the solution to the block has already occurred, then it is forbidden to move it in any direction.

Masonry reinforcement

When laying wood concrete blocks, it is necessary to follow the basic principles of reinforcement. First of all, reinforced bottom row masonry adjacent to the foundation (that is, the blocks of the first row are laid on a reinforcing mesh around the entire perimeter). Subsequently, the reinforcing mesh is laid every 3-4 rows. The use of reinforcement when laying arbolite blocks not only significantly increases the strength of the walls, but also contributes to a more uniform distribution of loads. Also, with uneven shrinkage of the house, reinforcement prevents the appearance of cracks in the walls of the building.

Reinforcing belts

In order to evenly distribute the load from the ceilings on the walls of arbolite blocks, it is necessary to equip reinforcing belts around the entire perimeter of the building. An armored belt is a tape (closed) made of monolithic reinforced concrete, on which floor slabs are laid or the roof truss system is supported. The width of the reinforcing belt is equal to the width bearing wall, and the height, as a rule, is not more than 30 cm.

To make an armored belt, we build a formwork, which we attach to the walls. Then put in it metal carcass and pour concrete.

Lintels over windows and doorways we reinforce with ready-made reinforced concrete (or metal) beams. The length of the support of such a jumper on the wall must be at least 20 cm on each side.

Elimination of cold bridges

To eliminate cold bridges that form when using conventional cement-sand mortar(normal consistency and without any additives), it is necessary to create effective thermal breaks in the masonry joints. This can be achieved in several ways.

Making a break with wooden lath. To do this, on the surface of the block (in the center) we place a rail (about 8-15 mm high, 40-50 mm wide), put the solution, wait until it “grabs” a little, remove our wooden fixture (a hollow space forms instead ), that is, we get an air cushion in the middle of the masonry joint, which will create a sufficient barrier for the penetration of cold into the room. Place the block on top.

Another way. To eliminate cold bridges, we use jute tape, which we lay along the entire length of the masonry in the middle of the wood concrete blocks. Then, on the sides of it, we apply a solution to the blocks and lay the next row of building materials. Thus, we create a heat-insulating belt in the gap of the masonry joint.

Important! Leaving the rail inside the seam “forever” is not recommended (over time, it will become saturated with moisture and begin to rot). But you can leave the jute tape.

We use polyurethane foam mounting tape (we make it ourselves from the substrate for the laminate). The algorithm of actions is the same as in the case of jute tape.

Bubble wrapping film can serve as a very economical and effective material for eliminating cold bridges. From the roll we cut off a strip 7-8 cm wide. Then we cut this strip into pieces 70 cm long (block length 50 cm plus thickness 20 cm). We fold the resulting strip into 3 layers to make a tourniquet (about 2-2.5 cm wide, 70 cm long). We fix it (using a conventional furniture stapler) on the horizontal and end surfaces of each block (enough in 3 places). That is, we lay the tourniquet in the form of the letter "G". We apply the masonry mortar on both sides of the bundle on the horizontal and vertical surfaces of the block. The resulting cavity made of air-filled porous polyethylene will be an excellent insulation that does not absorb moisture and does not respond to temperature changes.

In custody

The laying of wood concrete, made in accordance with all the rules, will not only increase the strength of the walls of the building, but also preserve the energy-saving characteristics of the entire structure as a whole.

Arbolite blocks - the material is not capricious, but peculiar. And if the task is set: to lay them with your own hands, then there are usually no problems with this process. The only question that private developers ask is whether it is necessary to reinforce wood concrete blocks. It is impossible to answer it unequivocally - yes, it is a necessity, or not, it is not necessary. Everything will depend on the design of the building.

What is wood concrete and its characteristics

Before you deal with the reinforcement of the wood concrete masonry, it is necessary to indicate that this wall material is made of lightweight concrete, in which wood chips are used as a filler. Of all materials with organic fillers, it is the most durable with excellent thermal insulation qualities.

Its outer surfaces are porous, which guarantees good adhesive properties blocks. But at the same time, the pores are filled with a large amount of masonry mortar, which leads to its high consumption. But this has its own plus - the ability to make the seam between the blocks thin, which provides appearance wall, similar to a monolithic structure. In addition, the seam is a cold bridge, so the thinner it is, the better.

In addition, the solution that has entered the porous structure of the block surface ensures high strength of the entire wall structure. In this regard, materials with a smooth surface are inferior to wood concrete. Therefore, developers may have doubts about whether it is worth reinforcing the wood concrete masonry. Everything will depend on the design of the building being constructed, its purpose and operating conditions. But, as practice shows, any structures erected from block materials must be reinforced. This applies to both masonry and the armored belt laid along the upper part.

How reinforcement is carried out

To begin with, three types of solutions can be used for laying wood concrete blocks:

1. Cement-sand mixture, as a bright representative of masonry mortars. Today, this material is represented on the market by sand concrete. different brands, although making it with your own hands in a concrete mixer or in a trough is not a problem. The main thing is to accurately maintain the proportions of the ingredients, where the cement-sand ratio is 1:3.
2. Perlite mixtures or in other words "warm". Instead of sand, perlite powder is poured into them - this is a finely dispersed volcanic rock. Perlite in solution acts not only as a filler, but also as a heater.
3. Adhesive composition for cellular concrete. This is the most ideal version of the masonry mortar for wood concrete.

So, the reinforcement of wood concrete begins immediately with the first row of stacked blocks. This is a strict requirement. For this, a standard welded reinforcing mesh made of steel wire with a diameter of at least 2.5 mm with cells of at least 50x50 mm is used. This mesh is sold in rolls 1.5 m wide and up to 25 m long. This is convenient because the roll can be unrolled and cut from it into the required number of segments of the required length and width, which will ensure seamless laying of the mesh. If you have to join the segments, and this will certainly be present at the joints of the external and internal walls, then the connection is made by overlapping within 15 cm with wire tying in three or four places.

The mesh laying process is standard, where there is one requirement - it must be located in the body of the masonry mortar. Therefore, a masonry mortar with a thickness of 10-12 mm is applied to the previously waterproofed foundation. A reinforcing mesh is laid on it with a slight recession into the finished mixture. There is another option, when the solution is applied with a layer of 5-6 mm, then the mesh is laid, on top is another layer of the mixture of 5-6 mm. After that, the laying of wood concrete begins.

The second option is much better. It allows laying in sections. That is, the grid laid on the masonry mortar can not be immediately covered top layer. And this makes it possible not to rush. You can carry out the process in a different way. The stacked segment of the mesh is rolled up. A solution is applied to the foundation, for example, 3 m along. The mesh is unfolded to this size, an additional layer is applied on top and masonry is carried out. The same goes for the next three meters.

It is necessary to reinforce the masonry from wood concrete blocks every 3 rows. If a one-story building is being constructed, then the reinforcing mesh can be laid less frequently - every 5-6 rows.

armored belt

Do I need an armored belt in a house made of wood concrete. A must, especially when it comes to high-rise building. It is poured in the basement, interfloor and attic. In the first floor, this is not necessary if, according to the calculations, the foundation of the building can withstand all the necessary loads. In this place, the armored belt is poured if the foundation structure is not a monolith, that is, it is assembled from blocks.

The whole point is that reinforced belt designed mainly to contain the loads emanating from the shrinkage of the house. It evenly distributes these loads around the entire perimeter of the building, preventing the walls from cracking.

Armopoyas for wood concrete can be poured in two ways:

1. A formwork is installed along the entire perimeter with a width equal to the width of the wall. The height is determined by calculations. The formwork is attached to the foundation or walls of the building long self-tapping screws, nails or other fasteners.
2. Special U-shaped wood concrete blocks are used.

Formwork reinforcement method

This is a traditional technology with the installation of formwork from boards or other flat materials. The main requirement is the strength of the structure, which, when pouring concrete, should not part to the sides. Therefore, the shields are fastened with through studs or wooden crossbars.

An important element of the armored belt of a wood concrete house is a reinforcing frame made of steel reinforcement. In fact, these are two lattices with cells of 20x20 cm, assembled from reinforcement with a diameter of 8-10 mm. They are installed vertically and connected to each other into a three-dimensional structure (cage) by crossbars made of reinforcement with a diameter of 6-8 mm. All connections are made using a knitting wire.

The reinforcing steel frame is installed on stands so that it is in the body of the armored belt. Therefore, in terms of dimensions, it should be less space, formed by the elements of the formwork and the plane of the foundation. As supports, you can use stones, pieces of concrete blocks, pieces of metal profiles.

The last stage is the pouring of a concrete solution made according to the recipe: cement-sand-crushed stone in a ratio of 1:2:2. Concrete must be poured simultaneously without long breaks between poured batches - no more than 2-3 hours. The solution must be subjected to vibration to remove air that enters the mixture during its kneading. And air is the pores inside the armored belt, which lead to a decrease in the strength characteristics of the structure.

You can remove the formwork in two to three days. But you can load the armored belt in 15 days, and preferably 28.

These are special blocks in which a longitudinal groove is made. The section shape can be rectangular or oval. It is necessary to pour concrete mortar into it with preliminary laying of reinforcement. This method simplifies several times the above procedure using formwork. Because U-shaped blocks are laid along the top row of the wall, like standard masonry elements, and serve as a fixed formwork.

It is important to understand here that a reinforcing frame made of steel reinforcement in the form of a cage or lattice is not used here. Just along the wall, two or three fit into the groove rebar with a diameter of 12-16 mm at a small distance from each other, connected by a knitting wire or not connected at all. The main thing is to lay the rods so that they are in the body of the poured concrete solution.

There are two important advantages of this method of constructing an armored belt for wood concrete:

1. Ease of work.
2. It turns out a warmed belt made of reinforced wood concrete.

The third option for the formation of an armored belt

With the advent of U-shaped blocks, the need for this technology of pouring the reinforcing belt has disappeared. Let's just label it for information.

This will require arbolite blocks of smaller width. For example, the width of the wall block is 300 mm, which means that you need a block with a width of 100 or 150 mm. It is impossible to find wall-type material of such dimensions, so the craftsmen simply cut solid blocks to the required dimensions.

The resulting masonry elements with a smaller width were laid on a wall or foundation so that there was an opening between them, where reinforcing bars were laid and concrete mortar was poured. Sometimes they did it the other way:

• on the front side (outer) a block with a width of 150 mm was laid;
• from the back installed boards or sheets of flat slab or sheet materials(plywood, OSB, etc.);
• a kind of formwork was obtained, the outer side of which was already insulated.

Conclusion

So, answering the question whether reinforcement is required for a wood concrete house, we can answer that this process is one of the important ones. It is with the help of reinforcement of walls and floors that it is possible to guarantee uniform shrinkage of the building without the appearance of cracks on the walls. In addition, these structures are often called seismic belts, which is very important in areas with seismic activity.