Reinforcement of a monolithic belt for aerated concrete. Armopoyas - all about its purpose, functions and installation

As a rule, a solid reinforced concrete belt is poured under such load-bearing structural elements. However, some amateur builders, apparently for reasons of saving time and materials, are trying to find ways to fix the Mauerlat on aerated concrete without an armored belt. Let's see how this is possible, and whether it is worth resorting to such a solution at all.

A few words about the importance of Mauerlat

What is a Mauerlat and why is it needed? To a person inexperienced in matters of construction, this tricky word often does not say anything at all. Meanwhile, we are talking about one of the most important load-bearing parts of the building structure.

What is the foundation - probably everyone knows. So, in terms of its functionality, the Mauerlat can be compared with a foundation tape. True, she is responsible for the loads transmitted from the entire building as a whole, and the Mauerlat is only for those that are formed during the operation of the entire roof structure - the truss system, roofing, insulation "pie", the inner lining of the slopes (if any) and etc.

And the loads here can be considerable, and what is most dangerous is to have a bursting orientation perpendicular to the surfaces of the walls, that is, to work for their destruction. It's all about the angles of the roof slopes - this is what gives such a decomposition of the force application vectors, both from the severity of the roof structure itself, and under external loads - snow and wind.

Such bursting point loads transmitted from the rafter legs are especially dangerous for walls lined with piece material - brick or masonry blocks (which includes aerated concrete). This means that it is necessary to distribute the drop-down load as evenly as possible along the entire length of the wall. And, again, by analogy with the foundation tape, this can be handled by a powerful wooden beam, which rests tightly throughout its entire length against the end of the wall.

The second remarkable quality of the Mauerlat is the significant simplification of installation work when installing the truss system. Agree that attaching each rafter leg to the main wall is much more difficult than, as they say, "tree to tree." With the presence of a Mauerlat, very wide possibilities for using various connection schemes come off, from “deaf” to movable, using a variety of fasteners.

As a Mauerlat, a wooden beam with a cross section of 100 × 100 mm and above is usually used (as a rule, depending on the massiveness of the roof structure, another 100 × 150, 150 × 150, 150 × 200 mm are chosen). Very often they rely on an unspoken, in principle, but effective rule - the thickness of the Mauerlat should be at least two thicknesses of the rafter legs.

Width - depending on the thickness of the wall on which it is installed. At the same time, they try to arrange the beam so that it does not fall flush with the surface of the wall either outside or inside. So it will be easier to protect the wood from the negative effects of the external environment, to insulate this rather difficult node in terms of ensuring normal thermal insulation. This rule is not mandatory, but if you read the advice of the masters, then all of them almost unanimously advise leaving at least 50 mm from the edge on each side.

It is possible to make a Mauerlat from a log, but such a solution does not seem to be optimal - the operations of attaching to the wall, and then inserting the rafter legs will become much more difficult and, accordingly, will require increased skills in carpentry.

It is clear that in view of the high responsibility of this element of the roof structure, for such purposes, they try to choose dried wood of the first grade, which does not have curvature, pronounced knotiness, cracks, signs of biological decomposition, and other defects.

For Mauerlat, selected hardwood is generally recommended. But finding such material is not easy, therefore, high-quality pine is most often used, but only subjecting it to a very picky choice: saving on quality in this case is completely unacceptable.

By the way, the Mauerlat may not be wooden. For example, if it is planned to create a truss system from prefabricated or welded metal trusses, then a steel beam will also be used as a power plate - usually a channel or an I-beam. However, in the practice of private construction, such solutions are rarely resorted to - wood remains a "classic".

Mauerlat may not be used on walls made of timber or logs (its role will be played by the last row - the top trim), and on frame houses - for the same reason. Sometimes they refuse the Mauerlat when the walls are built from a material that is durable, resistant to point and bursting loads (for example, concrete), and at the same time the roof structure involves attaching the rafters to the outer extension of the floor beams. For walls made of piece materials, it will not be possible to do without a Mauerlat in any case.

It is clear that in order for the Mauerlat to fully perform its functions, the reliability of its fastening to the wall should not cause any concern. With concrete, stone, brick walls - it's easier, since there are many ways to securely fix the timber at the end of the wall. For example, when laying ceramic or silicate bricks, bookmarks are made from wooden blocks. This makes it possible then to use ordinary steel brackets for fastening the Mauerlat. But to complete such bookmarks with aerated concrete is an absolutely hopeless task, you don’t even have to try, since no reliability will be provided. We have to look for other ways, which will be discussed later in the article.

On aerated concrete walls, Mauerlat is recommended to be performed according to a “closed circuit”, that is, in the form of a frame that completely encircles the entire perimeter of the building - this is how the maximum reliability of the structure is achieved. However, this is not always possible - for example, in the case when gables are laid out from the same foam blocks. This means that the more reliable the fastening of the beam to the end of the wall should be.

How is a gable truss system calculated?

In the course of the presentation, we have already once referred the reader to the size of the rafter leg - the section of the Mauerlat depends on this to a certain extent. But, taking into account the angles of steepness and all the drop-out loads - read in a special publication of our portal.

How can I attach a mauerlat beam to a gas silicate wall without an armored belt?

First of all, a builder who faces such a problem must clearly answer the question for himself - “Is it really not possible for me to pour a reinforced concrete belt so as not to have problems in principle?” Why? - Yes, because any of the options proposed below is not without certain shortcomings. And besides - the very possibility of installing a Mauerlat without an armored belt is rather doubtful, and is accepted with many reservations.

No matter how much you look, it is unlikely that you will be able to find intelligible criteria when experts say unequivocally - yes, you can do without a concrete armored belt on this gas silicate wall. There are only many "ifs" in which, it seems, one can hope for the success of such a montage.

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aerated concrete

• If the house or outbuilding is small (unfortunately, there are no evaluation criteria).
• If the roof has a not too complex and heavy structure (let's say that we are talking about simple ones from, for example, corrugated board or metal tiles - all other roofing materials, together with their crate, will be heavier).
• If the climatic conditions of the construction region do not imply a large snow load and wind pressure (and where is the guarantee that a weather anomaly will not happen?).
• If the design of the truss system will minimize bursting loads. This can be provided:

- The use of hanging stops, rigidly tied with horizontal puffs.

- The use of layered rafters, with obligatory support at the point of the ridge connection, if at the point of connection of the rafter legs to each other, a hinge connection is provided on the ridge, and the attachment point to the Mauerlat involves the use of movable, sliding joints.

In a word, the list of conditions in order to try to do without an armored belt (and even then without complete confidence in success) is quite large. And it is necessary, probably, to think ten times before choosing this particular path.

However, the Internet offers several ways to mount a Mauerlat beam directly on a gas silicate wall without pouring an armored belt. Let's try to understand them.

Mauerlat fastening with wire

One of the simplest methods, which is often used in the construction of brick walls. In this case, approximately 4–5 rows before the end of the masonry, bundles of steel wire with a diameter of approximately 3 mm (3–4 cores in a bundle) are laid between the rows so that they look out from both the outer and inner sides of the wall. The length of the release of these "pigtails" is made such that it provides coverage of the Mauerlat beam mounted at the end of the masonry and allows the reliable twisting and tightening of the wire loop without any problems. The location step of such leash bookmarks is usually chosen equal to the installation step of the rafters, so that the attachment points of the Mauerlat fall between adjacent rafter pairs.

When the wall is ready, it is laid on its end. Then a bar is installed on top, leveled, and then a wire loop is created and tightened. Tightening is usually carried out with the help of a crowbar (mount), achieving the tightest pressing of the timber against the wall.

It would seem - here it is, the simplest solution. However, take a closer look: all the examples shown are only on a brick wall. They write that this method also works well with gas silicate blocks, only the laying of wire "pigtails" is carried out approximately two rows before the end of the masonry.

They write something, but it was not possible to find a single reliable evidence of the reliability of such a method with gas silicate walls on the Internet.

According to personal feelings - will the wire under heavy loads, and even more so - with possible vibration, for example, in strong wind, work like a "hacksaw blade", gradually biting into the gas silicate block (which can be sawn with a hand saw)? After all, this is a violation of the integrity of the masonry, and a weakening of the fixation of the Mauerlat on the wall, with all the ensuing consequences.

In a word, not everything is so obvious...

Fastening the beam with anchors or dowels

It would seem - the simplest and most reliable way, proven by practice and time. Everything is so, but only if we are not talking about gas silicate. The increased fragility of this material may well give a surprise when a crack or even a chip forms when the anchor is tightened or the dowel is screwed in.

Of course, on sale in our time you can find a considerable range of fasteners designed specifically for aerated concrete walls. But, you see, it is one thing to fix furniture, interior items, or even a frame for wall insulation - and a completely different powerful one, which becomes the basis for the entire roof structure.

Considering that the holding properties of gas silicate are small, you will have to purchase anchors of maximum length - about 300 ÷ 500 mm, so that, taking into account the thickness of the Mauerlat beam, you can more or less reliably “hook” on the wall. But the cost of such long powerful anchors is considerable, so this must also be borne in mind.

The work on mounting the Mauerlat on the anchors is carried out approximately in the following sequence:

Illustration
	First of all, it is necessary to provide reliable waterproofing between the gas silicate and the stacked timber. Otherwise, at the place of contact of wood with other building material, a center of dampness will inevitably appear and, as a result, biological decomposition.
	For a waterproofing barrier, a strip of high-quality roofing material is quite suitable - it is laid so that it completely covers the entire end of the wall. If it enters a few on the sides, it’s not scary, since this one is easy to cut off later. The strip can be laid dry, that is, without the use of bituminous mastic.
	After that, a Mauerlat is laid on the end of the wall. In this example, a high-quality board 50 × 150 mm is used for it, which, by the way, looks a bit thin in terms of thickness. But the principle of fastening does not change from this.
	The beam is laid exactly in its place, as provided by the project, leveled.
	The necessary markup is carried out. In principle, in this case, it boils down to marking out the areas for installing the rafter legs - then the Mauerlat fastening anchors can be placed between them - and there will be no mutual interference.
	The place of attachment of the rafter leg is outlined. Anchors can be positioned arbitrarily, repeating the step of the rafters.
	Here it is, the anchor bolt. Let's make a reservation right away - in this example, an armored belt is still poured on top of the gas silicate wall, so the master uses relatively small anchors, 12 mm in diameter and 150 mm long. In mature concrete, such fastening will provide the required reliability. But if there is no armored belt, you will have to install the longest fasteners - up to half a meter.
	Further, a pen-shaped drill for wood (in this case, 12 mm in diameter) is installed in the drill, and through holes are drilled in the Mauerlat beam, up to the end of the wall. It is recommended to immediately sweep away the sawdust so that it does not fall back into the canal.
	After that, a puncher with a drill for 12 is used. Directly through a hole in the wood, a channel for the anchor is drilled into the wall material.
	After the hole is ready, an anchor is inserted into it. Further, the anchor must be hammered with a hammer for its entire length, until the washer stops under the nut into the wood.
	And the last step is to tighten all the anchors using the appropriate key, thereby firmly pressing the Mauerlat beam to the end of the wall.

Will such a connection be reliable? With concrete, yes. With gas silicate directly - the question is complex, even with a large anchor length. In any case, no studies or results of the study of experience on this issue on the Internet could be found - neither positive nor negative.

Let's focus on one more thing. Often, the length of the timber in order to lay out the Mauerlat along the wall in one piece is not enough, and you have to resort to splicing. Experienced carpenters can make very interesting and reliable interlocks, but for a non-professional, it will be enough to make a half-tree connecting knot. A prerequisite: at this place it will then be necessary to provide for fastening - an anchor or a hairpin in order to tighten the junction.

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corrugated board

A similar approach is also used in the corners where the beams of adjacent walls are joined - a locking connection, followed by tightening with the selected fasteners.

In addition, in order to tie all sides of the Mauerlat into the most rigid frame, reinforcement of the connection with steel brackets is practiced at the corners. One of the diagrams above shows this well.

Another tip - if you have to join two sections of timber on the wall, then you should strive to ensure that they are approximately the same length. For example, on a wall with a length 8,5 meters it is better to use bars not 6 + 2,5 , and, for example, 4,2 + 4,3 m.

Technological innovations - chemical anchors

A dozen years ago, few people heard about these innovative methods of fastening parts in various materials. Today, chemical anchors are widely available for sale, however, it is not yet possible to call them publicly available at a price.

By the way, many of the home craftsmen carried out similar fastening technologies without special chemical anchors - we are talking about those cases when a mixture of epoxy and a hardener was poured into the hole made, and then the part was inserted - a reliable connection was obtained in a day.

The advertising that accompanies such chemical anchors ascribes to them the highest strength properties. True, one can already meet consumer complaints, although, perhaps, they are related to the fact that there are a lot of low-quality fakes of such chemistry on the market. And if we talk about reputable manufacturers of such materials, then we should focus on the brands Sormat, Hilti, Nobex, Fischer, Tox, Tecseal, Tecfix, Technox, KEW and some others.

By themselves, chemical anchors can differ in the principle of their application.

• So, one variety has a capsule (ampoule) layout.

An ampoule is inserted into the hole drilled under the anchor, which contains a one- or two-component composition, which begins to quickly harden after mixing and contact with air.

After laying the ampoule, the anchor (pin) itself is inserted into the hole, and hammered to the required depth. When clogging, the anchor destroys the ampoule, sucking fills the entire space of the channel. Including between the walls and threads of the stud. At normal air temperature, after 25 ÷ 45 minutes, the composition completely polymerizes, hardens, provides reliable retention and immobility of the anchor even under considerable load.

• Another type of chemical anchors involves the use of cartridges (tubes) with a polymer composition (usually two-component) and a special dispenser gun. The gun is similar in design to the one we usually use with silicone sealants or "liquid nails". And some types of chemical anchors are directly designed for such simple guns.

In addition, depending on the material of the wall, additional devices can also be used. For example, let's see how a chemical anchor is installed, which is designed specifically for porous concrete.

Illustration	Brief description of the operation to be performed
	The illustration shows the possible components of a set of chemical anchors "Fisher" - these are the cartridges themselves with compositions of different hardening speeds, dosing guns. The channel for any chemical anchor always needs to be thoroughly cleaned of dust - for this there is a special pump for purging and pumping out, brushes of different diameters. A drill with a special nozzle allows you to make conical holes (just what you need for porous concrete). And, finally, various adapters, guide adapters, mesh bushings for hollow walls, and stud anchors themselves of various lengths.
	In this case, we are interested in the topic of the article namely the gas silicate wall - porous concrete.
	The drilling of the channel under the anchor begins. For this, a special drill with a round stop-limiter and a spherical nozzle is used.
	First, a straight hole is drilled - all the way to the limiter.
	The stopper rested against the wall, and thanks to the spherical shape of the nozzle, the hole begins to be conical - as shown in the illustration.
	When the channel is ready, the drill is placed straight and carefully so as not to break the accidentally narrowed top of the cone, it is removed from the hole.
	After that, they take a hand pump - it is necessary to thoroughly clean the channel from dust. Purge begins with the pump probe fully immersed in the hole.
	Then the pump probe is gradually removed from the channel without stopping the purge. If necessary, use a round brush of the appropriate diameter. This purging operation should be repeated at least four times - the presence of dust drastically reduces the reliability of the chemical anchor. Ideally, it is necessary to strive for the channel to be completely clean.
	After cleaning, a plastic sleeve is inserted into the hole. It will “ennoble” the edge of the hole and, most importantly, ensure the position of the inserted anchor (stud) perpendicular to the wall surface.
	Chemistry is getting ready to work. A cartridge is inserted into the gun, a mixer nozzle is screwed on. A small release of the composition is made on any surface - you need to make sure that all components are completely mixed - this will show an even color of the outgoing mixture.
	After that, the spout is inserted into the sleeve that limits the hole, and the filling of the cavity with the composite composition begins.
	Typically, the cavity is filled to about ¾ of its volume.
	Next, an anchor-stud of the required length is taken and carefully screwed (in the literal sense of the word) into the plastic mass that fills the conical cavity - for this, at this stage, the effort of the fingers is sufficient. It is important to ensure that the stud takes a position perpendicular to the wall - the guide sleeve will help with this, but it still does not interfere with checking. The pin is screwed all the way into the wall.
	It remains to wait only 45 minutes - and at normal temperature (about +20 °C) the anchor will be ready for load testing.

What else is said about the advantages of chemical anchors:

• The fastening is considered high-strength, durable - the service life is estimated at 50 years.
• The used polymer composite is completely inert to atmospheric, biological, chemical influences.
• When installing such an anchor, there are no bursting loads inside porous concrete, that is, the risk of a crack or chip is practically eliminated.
• At the same time, the penetration of the composite into the pores of aerated concrete adjacent to the drilled channel ensures the maximum degree of adhesion of the chemical dowel to the wall material.

Well, now - about the shortcomings. There are not many of them, but judge for yourself:

• The cost of chemical dowels is high, and mounting the Mauerlat will cost a very impressive amount. Moreover, our task requires very deep channels with their complete filling with composite - so a fair amount of cartridges will be required.
• Chemical anchors are not resistant to high temperatures. It is clear that on the Mauerlat, temperatures above 100 degrees, in principle, have nowhere to come from, but nevertheless ...
• No reliable data on the timing and results of the operation of chemical anchors for attaching the Mauerlat to aerated concrete without an armored belt have been identified. That is, there are suggestions that it should seem to work out well - but there are no results of the tests carried out yet. Maybe you want to be the first?

Video: Hilti Chemical Anchor Demonstration

Mauerlat fastening on embedded studs

If, even before attaching the Mauerlat, studs stick out from the end of the wall at the right distance from each other, the installation process is simplified to the limit.

• Marks for the location of the studs are transferred to the beam - for this it is enough to lay the Mauerlat on top and tap a little - the studs will leave marks that will become the centers of drilling holes.
• Further, a waterproofing strip is “pricked” on these studs.
• Then a beam with drilled holes is strung.
• Wide washers are put on the studs, nuts are baited - and a completely understandable procedure for pressing the Mauerlat to the end part of the wall takes place.

Everything is very simple, but except for one thing - how to fix studs into an aerated concrete wall. This is where the difficulties begin.

There are such tips - a deep, about 500 mm, hole is drilled in aerated concrete masonry, a hole with a diameter of about 3-4 mm larger than the diameter of the stud. The channel is then filled with masonry adhesive or cement laitance. After that, a hairpin is inserted into it until it stops - and in this form it is left until the solution has completely set.

It would seem easy, but some craftsmen who have tried this method are clearly not enthusiastic about it - solutions can shrink, it is difficult to avoid void areas, and the quality of such a knot is still not the highest. Some fasteners can become loose due to dynamic load or vibration, and this is fraught with a general weakening of the structure, the appearance of cracks on gas silicate blocks - with all the ensuing sad consequences.

Another option for early installation of studs. In this case, they are welded perpendicular to the metal plates, which will be placed in the masonry joint before installing the last row of gas silicate blocks. The shape of the plates does not play a big role - for example, they can be as shown in the illustration.

The main thing is that the plates create a support for the stud and at the same time work against the pulling load. With this approach, holes are drilled in the blocks of the upper row in advance, before they are installed in the masonry, then studs are inserted there, if necessary, the edges of the block are “aligned” so that it does not skew due to the thickness of the plate. After that, masonry is carried out - and when the wall is ready, there is immediately a number of embedded studs for mounting the Mauerlat.

And yet, the most reliable installation of embedded studs is ensured only when pouring a reinforced belt.

Is it reasonable to refuse to fill the armored belt?

And now, on the contrary, a direct question to the reader - how serious are your reasons to refuse this simple, but very reliable, proven, guaranteeing the strength of the roof structure being created, the operation of pouring the armored belt? Let's take another look at how simple and clear it all is before making a final decision.

The process of pouring a reinforced belt is nothing complicated!

Illustration	Brief description of the operation to be performed
	If you look at all kinds of instructions and manuals on the construction of houses from aerated concrete blocks, the issue of attaching a Mauerlat beam to the end of the walls without a reinforced concrete belt is not even considered. And only somewhere in the text can there be a modest mention: as an exception, for example, on small outbuildings, with roofs of a small area, if the climatic conditions of the region do not imply a pronounced snow and wind load, etc. In a word, practically at your own peril and risk. Is it really so difficult to fill in the armored belt in order to get away from this dependence - “if” at once?
	By the way, there is nothing particularly difficult in this, that is, something that even a novice builder would not be able to do. Manufacturers of aerated concrete building materials have provided in their assortment a special type of blocks designed specifically for the last row of masonry. They have a characteristic shape, for which they received the name U-blocks (for their resemblance to this letter of the Latin alphabet). In fact, this is a non-removable formwork made of aerated concrete in the factory for pouring a reinforced belt.
	Look at the illustration - it shows various sizes of aerated concrete U-blocks. The smallest block (200 mm thick) has a symmetrical shape, all the others have one wall thicker than the other. This thickened wall should look towards the street - it is made wider for reasons of maximum preservation of thermal insulation qualities.
	The dimensions of the “channel” for the reinforced belt itself are not so large, that is, a lot of concrete is not required, and it will not be difficult to make it for a medium-sized country house on your own right at the place of work. Moreover, you still have to fill it manually, since the concrete pump in this case will not be an assistant - the “tape” is too narrow and small. The amount of concrete for this operation will be discussed below. It would seem, why even think about ways to do without an armored belt - isn't it better to start pouring it right away? However, many are stopped by the fact that U-blocks, which require less material during production, are also significantly more expensive, since they are usually sold by the piece. But it turns out that such blocks can be made independently, using standard wall blocks, or you can do without them altogether by applying other technical solutions.
	So, U-blocks can be cut from standard wall blocks.
	To begin with, of course, markup is carried out - the width of the cut fragment ...
	... and its depth.
	Lines are drawn along which cuts will be made. In this case, the master decided to cut a “channel” 120 mm wide and 160 mm deep. This will be enough for a reinforced belt.
	If walls were built from gas silicate blocks, then the master must have a tool for cutting them. Usually this is a powerful hand saw with a large tooth. They begin to make cuts along the marked lines - to the depth of the “channel” being created.
	To achieve evenness of the cut in depth, the block is sawn in turn, achieving the desired immersion of the saw, first with one ...
	... and then on the other side. By the way, we don’t have a picture, but judging by the assurances of the masters, such even and identical cuts in depth can also be made with a circular saw. True, the release of the saw may be insufficient (well, you need at least 100 mm of cutting depth) - finally, you can work with a hand saw. Why not an option?
	A block with slots made is placed "on the butt".
	Next up is the perforator. A drill is inserted into its cartridge - the diameter is not so important (usually 8 ÷ 12 mm is enough), but it is better to take a longer length, about 400 mm, so that the drilled hole reaches approximately the middle of the block. A series of holes are drilled along the line defining the bottom of the “channel” being created, with a distance between their centers of the order of 15 mm.
	Then the block is turned over, and a similar operation is carried out on the opposite side.
	After that, a light blow with a hammer is usually enough - and the fragment cut from three sides falls out of the block. By the way, these fragments, if they have not split, should not be thrown away - they can still come in handy during construction.
	And to fill the reinforced belt, there remains such a home-made U-block.
	If necessary, the remaining irregularities can be trimmed with a chisel ...
	... sweep away crumbs and dust ...
	...and send the finished block to the place of their storage before laying.
	After a sufficient number of homemade U-blocks have been prepared, they move on to laying the last row of the wall. Work usually starts from the corner.
	Glue for aerated concrete is prepared from a dry mixture. Blocks are laid out sequentially. Everything is as in ordinary masonry - first, glue is applied with a layer of the desired thickness ...
	…this layer is then leveled and spread with a notched trowel…
	... and then another gas silicate U-block is installed. Work continues in a similar way until the entire row is laid out - until a “channel” is formed for pouring the armored belt.
	Particular attention is paid to the corners and at the junction of the walls - here you will have to think about how to join the U-blocks so that the "channel" for the armored belt is not interrupted. One of the options is shown in the illustration, but other solutions are quite acceptable.
	To some, this approach may seem overly time-consuming, and, moreover, accompanied by a large amount of waste. Well, this is true to a certain extent, and it is quite possible to apply other methods of creating formwork for the armored belt. Here is one of them. To create the walls of this kind of fixed formwork, in this case, gas silicate blocks of smaller thickness are used - they are often called additional ones. For example, you can use blocks with a thickness of 100 mm - to create an external wall.
	A number of these blocks are laid on the adhesive along the outer contour of the wall (the illustration shows only an installation example).
	Any armored belt, due to the specific thermal properties of concrete, always turns into a powerful "cold bridge". To reduce this disadvantage, it is advisable to immediately provide for a layer of insulation - lay along the outer wall of the fixed formwork (if the width of the wall block allows) extruded polystyrene foam with a thickness of about 50 mm.
	On the opposite side, the wall of our "formwork" is formed by a thin block, 50 or 75 mm thick. This row is also installed on gas silicate adhesive.
	The result is something like this picture - a channel for further pouring of the reinforced belt (shown in the illustration with the reinforcing cage already laid). By the way, you can slightly reduce the depth of the “channel” if it turns out to be too large. At the bottom, also on glue, you can lay fragments cut out from additional blocks, so that the depth is in the region of 150 ÷ ​​180 mm - this is quite enough.
	There are more options. For example, on the one hand - the same gas silicate block 100 mm and a layer of insulation, and on the other - just a wooden (or OSB) formwork, pressed to the surface or set exactly along the end of the wall.
	But the option and generally without the use of gas silicate blocks. Wooden formwork is installed on both sides. But from the outside, along the formwork boards, a strip of expanded polystyrene 100 mm thick and a width corresponding to the height of the “channel” created for the armored belt is laid.
	Here is this option, so to speak, live - with the insulation laid along the outer perimeter of the formwork. Although the insulation is not mandatory in this case, it should not be neglected - this has already been mentioned above. But on the inner walls it is not needed - if it is also planned to pour a reinforced belt there, then only wooden formwork on both sides will be enough.
	After the formwork (in any of its versions) is exposed, they proceed to knitting the reinforcing frame. As a rule, for the armo-belt under the Mauerlat, too much reinforcement is not required - four rods of a periodic profile (class A-III) with a diameter of 10 mm are enough.
	The spatial position of the reinforcement bars can be provided in various ways. The "classics", of course, are clamps made of smooth or corrugated reinforcement, with a section of 6 or 8 mm. - about the same as on a strip foundation.
	But often this scheme is also simplified - it still looks “too heavy” for an armored belt along the top of the wall. If you look at the examples presented, then many masters use very non-standard solutions. This one, for example, cut squares from a ready-made welded reinforcing mesh for a screed - and uses them as a kind of clamp templates.
	Binding is done in the usual way - with the help of steel binding wire.
	And such a picture is obtained after linking - a neat spatial structure of four rods of longitudinal reinforcement.
	And here is another original solution. Apparently, the owner has the opportunity to inexpensively (or even for nothing) get waste from the production of metal products. One can only envy such creativity!
	Be that as it may, no one cancels the rules for knitting reinforcement, especially in areas of reinforcement (longitudinal connection of rods, turns, junction areas). Therefore, appropriate bends, overlaps, clamps, etc. are made. - all according to the rules of the strip foundation. By the way, pay attention to an extremely important nuance. The presence of a reinforced belt leaves practically no difficulties for the subsequent fastening of the Mauerlat - matured concrete will perfectly hold even conventional expansion anchors. And yet, before pouring concrete, one more operation can be done - install the studs in advance, linking them to the reinforcement cage. After the belt hardens, the master will immediately have ready-made reliable fasteners for the beam.
	There are also several options for installing studs. So, for example, a guide hole is drilled under them in the bottom of the channel, and the stud itself is linked to the lintel of the frame reinforcing structure (as shown in the figure).
	The hairpin can also be located with an offset from the center line of the armored belt - it all depends on its width and the planned place for laying the Mauerlat. The figure shows how the embedded stud is tied to the longitudinal reinforcement rods.
	Here it is shown how, for the sake of economy, threaded stud lengths are simply welded to transverse reinforcement stirrups. True, for this it is already necessary to have a very good command of the skills of electric welding.
	If you screw a nut at the bottom of the stud and put on a wide washer, the reliability of the resulting fastening will increase significantly. After the full maturation of the poured concrete belt, it will be almost impossible to pull out such a hairpin.
	The step of installing the studs is usually taken the same as the step of the future installation of the rafter legs. At the same time, it is desirable that these Mauerlat attachment points fall between the rafters - so that they do not interfere with further installation operations.
	After installing and linking the studs, it is recommended to close the upper threaded part, together with the baited nut, with a stretch film - so that the thread does not clog when pouring concrete.
	It is necessary to ensure that the reinforcement rods are located at a certain distance from the walls of the improvised "formwork" - so that a protective layer of concrete is created. For these purposes, you can use special liners - they will provide the necessary clearances from both the bottom and the sides.
	Concrete is being prepared. As a rule, for such an armo-belt, the M200 concrete grade is sufficient (but not lower). In a medium-sized house, a large amount of concrete is not required for these purposes - it is quite possible to do it yourself in a concrete mixer.
	Then the finished solution is fed up (by buckets), and gradually the “channel” of the armored belt is filled with it.
	It is very important to ensure that when pouring there are no unfilled voids. To do this, the poured concrete is carefully “bayoneted”, that is, it is pierced along the entire length of the filled area with a piece of reinforcement or a pointed wooden lath - this will allow air bubbles to escape.
	After “bayoneting”, the solution is compacted as much as possible with a trowel or spatula, while leveling the surface of the created belt.
	So they sequentially move on, along the entire length of the created belt.
	The belt is filled and aligned. This illustration shows a variant without studs - the owner assumes the use of conventional expansion anchors for mounting the Mauerlat.
	But the option - with linked mortgage studs. After pouring the belt and its final maturation, for the masters who will deal with the truss system, there are ready-made fasteners. In any case, the armo-belt must be given time for high-quality maturation - it is advisable to start further robots no earlier than a month after pouring.

As promised above - a few auxiliary materials:

Reinforcement of the strip foundation - how to do it right?

It was already mentioned in the table that the principles of spatial reinforcement of the autumn belt are similar to the foundation tape - especially in matters of reinforcement at intersections, junctions and at corners. Details are given in a special publication of our portal. And in another article are given. Plus, in both articles there are convenient calculators for calculating materials.

And, finally, a calculator that will help you quickly and accurately determine the required amount of M200 concrete for pouring the armored belt, and the number of components for its manufacture.

When erecting block rooms, an important step is the arrangement of a reinforced belt. It is laid at the end of each floor, which is necessary to stiffen and strengthen the building. In the absence of skills in construction, it is better to entrust the procedure for creating an armored belt in a house made of aerated concrete to experienced specialists. And you can also learn the basic subtleties of the work and do it yourself.

General information and purpose

The main purpose of the monolithic aerated concrete belt is to ensure the reliability and durability of the house. The point is that during operation wall structures can be subjected to a wide variety of stresses, including:

1. Wind.
2. Uneven shrinkage of important elements.
3. Temperature fluctuations that can occur during the change of seasons and even during the day.
4. Soil subsidence under the weight of the foundation.

A reinforced belt (another name is a seismic belt) is able to take on part of the load, thereby extending the service life of the structure and preventing its destruction. As you know, concrete has the ability to cope well with compressive loads, while the presence of built-in reinforcement maintains the rigidity of the walls under tensile effects.

The tandem of two materials allows houses made of aerated concrete not to deform under enormous loads that exceed the norms. The design provides the necessary stiffening rib in the room from gas silicate materials, which significantly extends the service life of the building and prevents its destruction. The need to equip a seismic belt during the construction of a house made of aerated concrete is due to the following reasons:

There is one main requirement for reinforced belts - continuity and reliability. It is provided by means of a circular pouring of a section of reinforced concrete.

Before starting installation work, it is important to carry out a lot of calculations and choose the right size. The width of the future structure should correspond to the width of the wall where it will be installed, and the height should not be less than 18 centimeters. It is the height accuracy that plays a key role in the rigidity of the armored belt.

Formwork preparation

Most modern people trust the procedure for erecting a seismic belt to experienced specialists. In the absence of building skills, such a solution may be optimal, however, if you make a little effort and understand the step-by-step guide, then you can make a reinforced belt for a gas-block house with your own hands.

So, the whole process is conditionally divided into the following stages:

In fact, such a process is not much different from arranging jumpers in windows.

After the calculations, you can start preparing the formwork. In most cases, a similar structure is erected from prefabricated parts, for example, large shields from boards. And also instead of boards, you can use furniture panels. The finished formwork is fixed on the wall structure:

1. In the side part, using pieces of rebar or wire.
2. From above (for this, stiffening ribs are constructed in advance from wooden scraps, which are nailed to the top of parallel formwork panels in increments of one and a half meters).

To prevent the structure from shifting, the heaviest part is additionally fixed with reinforcement. As for the thickness of the boards of the shield, it is determined by the height from which the concrete solution will be supplied. The algorithm is simple: the higher the height, the thicker the formwork should be.

To prevent leakage of the solution through all sorts of cracks and gaps, any leaky corners and turns must be carefully covered with sealant.

Next, it is necessary to carry out the installation of a frame made of reinforcement, which consists of durable steel elements with a thickness of 12 mm and a knitting wire. The structure is installed inside the formwork directly on special plastic stands (often they are replaced with wooden bars 3 cm wide).

Important Tip: at the stage of frame production, it is better not to weld the elements. The fact is that such an approach violates the strength of the structure and causes the development of corrosion processes inside the concrete.

Then the frame is covered with a concrete solution, and the formwork is dismantled using a nail puller after a predetermined period of time. In summer, it is 24 hours from the moment of installation, and in winter - 72 hours.

It is no secret that concrete is significantly superior to gas silicate in terms of thermal conductivity, therefore, it is possible to use a similar method of erecting formwork only if there is a thorough external wall insulation. Otherwise, the wall structures will be subject to freezing in the zone of the armored belt. However, the use of the following technique prevents such a nuisance.

To avoid significant heat loss, fixed formwork is used at the junction of concrete and gas silicate. To create it, it is customary to use factory U-blocks with a standard box shape. The construction process itself consists of the following steps:

If you use this technique, then the need to mount and dismantle the formwork structure will simply disappear, while the speed of work will increase significantly. However, U-shaped blocks are significantly more expensive than classic wooden shields. In addition, in this case, it is necessary to additionally saw aerated concrete for formwork.

In addition to the above methods, a combined method can also be used to install the frame. It consists in laying out blocks with a thickness of 150 millimeters on the outer parts of the walls, as well as the construction of formwork from wooden panels inside.

When arranging an armored belt on aerated concrete for wooden floors, it is important to pay due attention to the insulation of the future structure. This is required only in cases where the project of the house does not provide for comprehensive insulation of the outer part of the walls. When performing such work, various materials with good thermal insulation properties are used. Among them:

Residents of mid-latitudes can insulate their homes with a material 50 millimeters thick. It must be cut into strips that correspond in size to the height of the reinforced belt, and then installed inside the formwork from the side of the outer wall. In addition, it is not necessary to fix the insulation, as it will be securely pressed with mortar. Reinforcement and pouring with concrete

The future frame is created on the basis of 4 or more longitudinally placed rods with a diameter of 10-14 millimeters (the exact dimensions depend on the project). The shape of the structure in cross section should be square or rectangular. After that, the reinforcement is fixed to the main elements of the frame by means of a steel wire with a diameter of 6–8 mm. The maximum allowable step is 40-50 millimeters.

As for the distance between the edge of the seismic belt and the reinforcement, it depends on the operating environment. The exact figures are provided in the relevant documentation. The finished frame must be placed in the formwork, and then covered with a mixture of concrete.

Experts recommend pre-calculating the required number and dimensions of reinforcement for a concrete belt in order to buy it along with materials for reinforcing the foundation and walls. This way you can save on shipping. It is also better to buy goods at metal depots, where they are sold much cheaper than in construction hypermarkets and official retail outlets.

If we are talking about the armored belt, which was built under the Mauerlat, then before pouring, it is necessary to install mounting studs. Otherwise, you will need to make holes for the studs in the finished frame, which requires additional time and effort. Before pouring concrete, the studs are covered with polyethylene (you can replace it with ordinary plastic bags, for example, from under sandwiches, and secure with tape). This action will prevent concrete from getting on the thread.

When choosing concrete, you need to use products with a brand of at least M200, as well as crushed stone. And although the brand is determined by the designer, most often a mixture under the number M250 with a filler of crushed gravel is used for pouring.

The structure is poured evenly over the entire volume of the formwork by means of a concrete pump with a special funnel, which is equipped with a locking mechanism. If the volumes are small, then you can use the manual method of filling the armored belt. To do this, you will need to transfer the solution in buckets. Upon completion of work, the mixture should be compacted by bayonet or by vibration. And you can also use a regular construction trowel.

Often instead of a metal armored belt for aerated concrete a brick belt is installed under the floor beams. In fact, this is the usual laying of bricks, which is additionally reinforced with reinforcement between the rows. The use of such structures is not recommended, due to low strength and a host of other shortcomings. Even the presence of reinforcement does not greatly improve the strength of such a belt.

In addition, two or three rows of bricks are not able to provide a stable distribution of the load on the wall, which can cause all kinds of deformations and cracks. In the worst case, a complete destruction of the wall will occur, so it is highly discouraged to allow such a risk. However, unscrupulous builders often use reinforced brick structures, trying to simplify their work and save money.

It is important to understand that the installation of a reinforced belt for aerated concrete walls is a very important stage of construction, which must be taken with all responsibility. Only a high-quality seismic belt can ensure the reliability and durability of the building, regardless of environmental influences.

Is it necessary to build an armored belt for gas silicate structures in all cases? Not really. After all, if we are talking about the construction of a small country house, then the walls can be strengthened in another way, cheaper and simpler. It is enough to place metal studs in the wall and concrete them. Fasteners are installed 2-3 rows from the top of the masonry, while they must completely pass through the timber.

When erecting more complex buildings, the presence of a reinforced belt is a prerequisite and a guarantee of a long service life of the house.

In this article, we will figure out why we need an armored belt on aerated concrete. The basic requirements for this structural element will be considered in detail, and you will also learn how to properly make an armored belt for aerated concrete on your own.

The armored belt for aerated concrete is a tape structure made of monolithic concrete, repeating all the contours of the building wall. In gas-block houses, this belt is a necessary element that significantly improves the strength characteristics of the entire building.

In order for the reinforcing belt not to be the weak link of the house in terms of thermal insulation, the technology provides for the creation of belts not for the entire width of the wall, but with an indent from its inner side.

In this case, the minimum width of the belt should be 25 centimeters for brick and 20 centimeters for concrete. The free space formed after pouring the armored belt is filled with heaters and closed with a foam block fitted to the size.

We will also give reviews of builders specializing in the construction of foam concrete houses, which will help you get a complete picture of the need to equip a reinforcing frame for expanded clay concrete blocks:

Igor, 49 years old, Moscow:

For the past seven years, my team has been using foam concrete as the main building material, and I have heard only positive feedback from customers about our work.

The number of fans of this material, since its appearance on the domestic market, has grown significantly. We install armored belts on aerated concrete in every house we have built.

I believe that the reinforcement frame is absolutely necessary for foam concrete, and the manufacturers' statements that the strength of the blocks is already enough for the installation of any floors do not correspond to reality. As for me, it’s better to play it safe once again and consolidate the work than to bite your elbows later.
Oleg, 45 years old, Rostov:

We build houses from gas blocks. We install the armoframe without fail, especially for hanging rafters and to fix the ceilings from concrete slabs. Recently, he built a utility room for poultry in his summer cottage, using a cinder block as a building material.

It was equipped with a brick reinforcement frame, because I am sure that the “doctor prescribed” it to be fixed to all buildings made of building materials based on foamed concrete.

2.3 Do-it-yourself armo-belt arrangement (video)

If a reinforced belt is created on the structure, the building is able to withstand various loads that usually act during operation. Various processes occur during the operational period of the building - it has to face:

• with temperature fluctuations
• with uneven shrinkage of the soil,
• with the influence of weather conditions,
• with soil movement.

And only an armored belt on aerated concrete is able to normalize the situation. The serious load that it experiences causes deformation of the walls and even their partial destruction, so you need to take care of additional reinforcement in the form of a reinforced belt.

What is a reinforced belt for?

Experts note that aerated concrete blocks have one negative side, which is the poor tolerance of point loads, which are created by all kinds of fasteners.

When a heavy structure, such as a roof, is attached to an anchor bolt, aerated concrete blocks do not always cope with such loads and are covered with deep cracks. To make the structure stiffer and stronger, a reinforced belt is used.

Thus, the load is evenly distributed throughout the structure, and point effects of increased force do not occur. Without an unloading reinforced belt, they will not last long in their normal form, so you need to quickly solve this problem.

And in some cases, even two reinforced belts are used, especially if it is planned to build two levels of aerated concrete blocks.

Creating a reinforced belt

Before forming an armored belt on aerated concrete, it is necessary to first complete the formwork. The most common way to create formwork is to use boards from which a frame is made along the entire length of the future reinforced belt.

You need to decide on the height of the reinforced belt, and it is usually about 30 centimeters. Just a wall of aerated concrete blocks has such a thickness.

To fix the wooden formwork, you need to use self-tapping screws that are screwed into the aerated concrete wall. It is important to fix the lower part of the frame, and in the rest of the frame it is necessary to provide transverse ties for additional strength. If the formwork structure is not strong enough, it will not withstand the pressure of the concrete mix.

Moreover, it is desirable to place the armored belt on aerated concrete deep into the wall, and if after drying there are unfilled gaps, it is placed in them.

Another type of formwork is a reinforcing cage with a high degree of strength. Depending on the weight of the concrete mixture, you need to use a certain number of rods for the frame. It can be two thick rods, between which jumpers are welded.

This formwork design will resemble a metal staircase. For more powerful metal frames, more bars are used to withstand severe loads.

Reinforced belt design

In order for the armored belt on aerated concrete to be slightly raised, it is enough to use pieces of stone of a given thickness. The reinforcing cage must be completely tied with wire so that concrete mortar does not seep through large gaps.

You can also make a welded reinforcing cage. You can use electric welding for this, or you can use gas welding, which runs on a mixture of oxygen and acetylene. You can read more about technical acetylene and its use, for example, here www.gaz-kom.ru/price/73/. However, you can also buy it there.

Do not forget about the level at which the metal frame should be mounted so that the reinforced belt is even.

In order for the reinforced belt to turn out strong and quickly harden, it is best to use or even use higher grades. If you plan to prepare the concrete mix yourself, you need to correctly observe the proportions of crushed stone, cement and sand.

In the process of preparing the solution, you need to gradually add water and get the optimal consistency for pouring into the formwork.

The reinforced belt requires a large amount of concrete mix, so it is advisable to use special equipment, such as a concrete mixer, to speed up the mixing process. Moreover, the maximum effect of a reinforced belt on an aerated concrete structure is achieved only with a single pouring of the concrete mixture.

If concrete is poured several times, the solidity of the structure is broken, and such a reinforced belt will not last long.

Armopoyas for aerated concrete under floor beams

In the construction industry, progressive technologies are being introduced, new materials are being created. The popularity of cellular types of concrete used for housing construction has increased. Aerated concrete is widely used, which has many advantages. However, the material has insufficient strength and requires reinforcement to prevent cracking. To eliminate the problem, an armored belt is installed on aerated concrete. This increases the resistance of the walls of the building to loads and the strength characteristics of the structure.

The construction of a monolithic reinforced concrete structure along the perimeter of the building allows you to strengthen areas prone to cracking. These are the main walls that perceive the loads of the floor, door and window openings. The monolithic belt prevents the impact of structural deformation as a result of wind loads, seismic activity, soil reaction, and also allows fastening under floor beams.

The self-construction of an armored belt for aerated concrete requires certain preparation, special knowledge, and the use of high-quality materials. Let us dwell on this technology in detail, consider,.

The armored belt is a structure along the entire perimeter of the upper walls of a reinforced concrete building

Material Features

When deciding to use aerated concrete for the construction of walls, you should familiarize yourself with the properties of the material and its performance characteristics. This will make sure that the choice for construction work is correct. The manufacturing technology provides for the formation of air cells in the concrete mass.

It is thanks to the air cavities evenly distributed in the concrete monolith that the material has improved thermal insulation characteristics and is used for the construction of buildings that do not need special insulation. The use of aerated concrete for the construction of main walls significantly reduces the cost of space heating.

Aerated concrete has many positive characteristics. Main advantages:

• increased thermal insulation coefficient, which allows to reduce the cost of maintaining a comfortable temperature regime by 25%;
• resistance to negative temperatures, allowing the material to maintain integrity under the influence of multiple freezing cycles;
• increased soundproofing characteristics, making it difficult for the penetration of extraneous noise;
• ecological purity of the material that does not adversely affect human health;
• the possibility of accelerated processing and cutting on aerated concrete without the use of special equipment, which allows you to give the material the required configuration;
• small mass, due to which the load on the foundation is reduced and the process of transporting aerated concrete products is facilitated;
• the impossibility of the formation of mold, fungus and decay on the surface and in the depths of the array.

If the reinforced belt on aerated concrete was created immediately before the construction of the roof, then a Mauerlat is laid on top of it

To prevent cracking of the aerated concrete mass, caused by reduced strength characteristics, the armored belt for aerated concrete allows. Strengthening the aerated concrete structure with a reinforcing cage and a durable concrete solution is carried out in problem areas that need to be strengthened.

Device and purpose

How is the armored belt for aerated concrete arranged? The design is a monolithic contour closed around the perimeter of the building, made of M300 concrete and steel reinforcing cages. To ensure the stability of the building to the effects of external and internal factors, strong reinforcing cages are installed at different levels of the structure. They are intended for the following purposes:

1. Compensation for efforts associated with shrinkage of the base.
2. Ensuring the stability of the structure during heaving of the soil.
3. Formation of a structure resistant to gusts of wind.
4. Strengthening the supporting surface of the walls, perceiving the load from the roof.
5. Ensuring the possibility of building a building with an inclined surface of the soil.
6. Preservation of the integrity of the building, located in areas with increased seismic activity.

Before you make a reinforcing belt on aerated concrete with your own hands, you need to thoroughly understand what exactly it is intended for and what important functions it performs

The impact of these factors on aerated concrete walls that are not reinforced with a reinforcement circuit can violate the integrity of the building. Possessing a simple design, a monolithic belt is necessary for a building erected from aerated concrete composite.

What caused the need to strengthen aerated concrete?

During the construction of buildings, there are certain design features that make it necessary to make an armored belt on aerated concrete. Let's look at these factors:

• fasteners used when installing a truss structure cause a local impact on the supporting surface, which is prone to cracking that violates the integrity of the array;
• the supporting structure of the roof based on hanging rafters creates bursting loads that tend to displace the main walls. The monolithic belt dampens the spacer forces and distributes them proportionally over the upper tier;
• a monolithic reinforcing contour makes it difficult for walls to shrink, which differently perceive the acting forces.

There is no need to doubt whether an armored belt is needed for gas-filled concrete? It is necessary, as it performs an important function - it compensates for loads, ensuring the integrity of the structure.

It should be noted that it also contributes to the uniform distribution of all possible loads along the wall.

Problem areas

To strengthen the loaded areas, an armored belt is formed on aerated concrete. The reinforcing contour is performed at different levels. Let's dwell on the areas requiring reinforcement:

1. The area between the foundation and the first row of aerated concrete masonry is subject to significant forces from the building wall and ceiling. The height of the armored belt is 40 cm, which allows you to proportionally distribute the load transmitted by the mass of the structure to the base.
2. every 4th block is made with a steel mesh or reinforcing bars.
3. The supporting surface of the main walls, which is the basis for the floor beams, perceives the mass of the roof. For reinforcement, steel bars with a diameter of 12 mm are used, combined into a closed reinforcing contour, distributing forces from the roof support structure around the perimeter of the building.
4. Openings for doors and windows require strong reinforcement. Their reinforcement is carried out by steel rods with a diameter of 10 mm, placed in the grooves of aerated concrete blocks. After installing the rods, the grooves are concreted, ensuring the strength of the openings that perceive the mass of the masonry.