The need to create an armored belt under the Mauerlat when constructing a roof is not always obvious to novice builders. They often have the wrong idea about reinforced reinforcement of the base for the construction of a roof as something unnecessary and superfluous. However, the armored belt is an important intermediary that distributes the load of the roof onto the walls of the building. Let's look at why an armored belt under the roof is needed, what functions it performs and how to install it yourself.
In this article
The need for an armored belt
Let's start looking at the reinforced roof base with its main functions.
Load conversion
The rafter legs transfer the load to the mauerlat, the main concentration of which is in the places where the rafters support the walls of the house. The task of the Mauerlat and armored belt is to transform this load, making it uniform. The Mauerlat is subject to two types of loads. This is the weight of the roof itself, the snow accumulated on it, the effect of gusts of wind on the roof and other natural phenomena.
Another load is associated with the bursting of the building walls by the rafters. As the weight of the roof increases, it increases significantly. Modern materials for the construction of buildings, such as expanded clay concrete and aerated concrete, with a number of positive characteristics, are not able to withstand such a bursting load. Before installing the Mauerlat on them in mandatory need to create reinforced belt.
Brick walls are more resistant to point loads, so to install the Mauerlat on them, it is enough to use anchors or embedded parts. However, experts recommend the use of armored belts for brick walls if the building is being built in an earthquake-prone region.
Attaching the roof to the house
The most important and main task of the Mauerlat is to firmly attach the roof to the house. Thus, the Mauerlat itself must be securely mounted to the building. 
The main tasks of a reinforced roof base can be reduced to the following points:
- Maintaining the strict geometry of the building in any situation: seasonal soil fluctuations, earthquakes, shrinkage of the house, etc.;
- Alignment of walls in horizontal projection, correction of inaccuracies and flaws made during the construction of walls;
- Ensuring rigidity and stability of the entire structure of the building;
- Uniform and distributed distribution of the roof load on the walls of the building;
- Possibility of strong attachment to a reinforced base important elements roofing, primarily Mauerlat.
Calculation of a reinforced base for a roof
The process of reinforcing the base under the Mauerlat begins with planning and calculations. It is necessary to calculate the dimensions of the armored belt. According to building standards, it should be equal to the width of the wall, and not less than 25 cm. The recommended height of the reinforced base is around 30 cm. The armored belt and the mauerlat laid on it should encircle the entire house.
If the walls are built from aerated concrete, then the top row is made of stone in the shape of the letter U, which creates the formwork. It is necessary to lay reinforcing elements in it and fill the entire structure with cement mortar. 
Before the actual start construction work it is also necessary to prepare the necessary tools and Construction Materials. To create a reinforced base for the roof you will need:
- Concrete mixer for high-quality mixing of cement mortar;
- A specialized vibrator that accelerates cement mortar in the formwork, preventing the creation of air voids in the structure;
- Materials for the construction of formwork;
- Fittings.
Installation technology
Installation of the armored belt begins after masonry work. It is necessary to wait until the masonry is completely dry.
Creating formwork and laying reinforcement
The first stage is the construction of formwork. In buildings made of aerated concrete blocks, the outermost row of masonry is made of blocks in the shape of the letter U. If these are not available, then the outer part of the formwork is created from sawn 100 mm blocks, and the inner part from boards. Installation is carried out in strict compliance with the horizontal level.
A frame made of reinforcement is laid in the formwork. Its longitudinal part is formed from 4 reinforcement rods with a diameter of 12 mm. Transverse fastenings are made from rods of 8 mm diameter, maintaining a pitch of no more than 25 cm. In projection, the frame looks like a square or rectangle. The frame parts are mounted with an overlap of up to 20 cm. The joints are connected with knitting wire. In solution, such a reinforced frame exists as a monolithic one.
Laying the frame requires compliance with certain rules:
- The thickness of the concrete from the frame to the formwork is at least 5 cm;
- To comply with this rule, place stands made of bars of the required height under the frame.
An important part of the work is strengthening the formwork frame. If this is not done, then it will collapse from the weight of the concrete. This can be done in various ways:
Installation of fasteners for the Mauerlat
After working with the formwork and laying the reinforcement, you can begin installing fasteners for the Mauerlat. We recommend using threaded rods. It is convenient to purchase studs with a diameter of 12 mm. The length of the studs is calculated taking into account the fact that their bottom is attached to the frame, and the top protrudes above the Mauerlat by 2-2.5 cm.
Installation of studs is carried out taking into account:
- There is at least one stud between two rafters;
- The maximum installation step is no more than 1 meter.
Pouring with cement mortar
The main feature of the reinforced base for the Mauerlat is its strength. This can only be achieved by pouring the concrete solution at a time.
For creating concrete mixture Concrete of at least M200 is used. The best mixture for filling the belt is prepared according to the following proportions:
- 1 part cement M400;
- 3 parts of washed sand and the same amount of crushed stone.
The use of plasticizers will help increase the strength and speed of hardening of the mixture.
Since creating an armored belt requires a lot of mixture at once, it is advisable to use a concrete mixer and a special pump to supply the solution. In the absence of equipment, the help of several people will be required to prepare and continuously supply the finished mixture.
After pouring concrete into the formwork, it is important to expel all air from any possible air pockets. For this, a special device, a vibrator, and simple fittings can be used, with which the mixture is pierced along the entire perimeter.
Mauerlat installation
Removing the formwork from the armored belt is possible as soon as the concrete has hardened sufficiently, and installation on the Mauerlat structure can begin no earlier than 7-10 days after pouring the armored belt.
Before laying, the Mauerlat parts must be specially prepared:
- The Mauerlat timber is treated with antiseptics;
- Connecting it individual elements are performed using the method direct lock or oblique cutting;
- The Mauerlat is applied to the armored belt and the places for the pins are marked. Holes for fastenings are drilled.
Laying the Mauerlat is preceded by covering the reinforced base with a layer roll waterproofing As a rule, roofing material is used for these purposes.
The Mauerlat is secured with a large washer and nut; locknuts are used for security. After tightening all the fasteners, the remaining tops of the studs are cut off with a grinder.
Let's sum it up
A reinforced base for the Mauerlat is more of a necessity than a luxury. Roof structure has a rather large impact on the walls of the house, which, although distributed evenly thanks to the Mauerlat, can negatively affect the strength of the entire building.
The creation of an armored belt is necessary in buildings made of gas and expanded clay concrete due to the fragility of these materials, in areas with high seismic activity. It is also advisable to strengthen the walls under the Mauerlat when creating heavy roofing structures.
Reinforcement of the upper part of the walls is not difficult work, requiring the involvement of specialists. If you follow a number of rules and involve assistants, it can be done on your own.
Any developer, planning to build a house from aerated concrete, is faced with the need to manufacture an armored belt (it is also called a seismic belt). The armored belt on aerated concrete is a monolithic reinforced concrete strip poured along the entire perimeter of the walls (between the first and second floors, etc.). This element is necessary to evenly distribute the load and connect the walls together. This reduces the risk of cracks due to uneven shrinkage of the building. The armored belt is also placed under the Mauerlat when installing the roof.
Maxim Pan User FORUMHOUSE, Moscow.
You cannot attach timber (mauerlat) directly to aerated concrete using studs. If this is done, then over time, under the influence of wind load, the fastenings will become loose. When installing attic floor armored belt on aerated concrete with wooden floor will redistribute the point load from the beam to the entire wall.
An illustrative example is a forum member with the nickname mad-max which comprehensively answers the question, when you need an armored belt in a house made of aerated concrete . He did not have time to fill the armored belt under the Mauerlat, and the house went into “winter.” Already during the cold weather, the arched openings under the windows in the house cracked exactly in the middle. At first the cracks were small - about 1-2 mm, but gradually they began to increase and for the most part opened up to 4-5 mm. As a result, after the winter, the forum member poured a 40x25 cm belt, into which he installed anchors under the Mauerlat before pouring the concrete solution. This solved the problem with increasing cracks.
mad-max User FORUMHOUSE
I would like to add to this that the foundation for my house is strip-monolithic, the soil is rocky, there was no movement of the foundation before I started building the house. I believe that the reason for the appearance of cracks was the lack of an armored belt under the Mauerlat.
An aerated concrete house, and especially a two-story house, needs an armored belt. When making it, you should remember this rule:
The main condition for the correct “operation” of the armored belt is its continuity, continuity and looping along the entire perimeter of the walls.
There are several options for constructing an armored belt in aerated concrete house. The production of an armored belt begins with the calculation of its cross-section and the choice of the type of formwork - removable or non-removable, as well as the “pie” of the entire structure.
Eyeonenow User FORUMHOUSE
I am building a house from aerated concrete 37.5 cm thick, with brick lining and a ventilated gap of 3.5 cm. I do not want to use special factory-made U-blocks for pouring the reinforced belt. I saw on our forum the following diagram when building a house, how to insulate an armored belt - on wall block installs a partition block 10 cm thick, then insulation (EPS) is applied, and it is installed from inside the house removable formwork. I also saw an option where the insulation is pressed close to the brickwork. With this scheme, a belt of greater width is obtained.
To understand which option to choose, let’s turn to the experience of FORUMHOUSE experts.
44alex User FORUMHOUSE
I built a house from aerated concrete 40 cm thick. In my opinion, a ventilated gap of 3.5 cm between the wall and the cladding is not enough; it is optimal to leave a gap of 5 cm. If you look at the “pie” of the armored belt from the inside out, it was as follows:
- removable formwork;
- concrete 20 cm;
- EPPS 5 cm;
- septum block 15 cm.
They call it an armored belt reinforced concrete structure, which is designed to strengthen the walls of the house. This is necessary to protect the walls from loads arising under the influence of external/ internal factors. External factors include wind exposure, terrain slope/hilliness, floating soil and seismic activity of the earth. The list of internal factors includes all household construction tools, used for interior decoration Houses. If you make an armored belt incorrectly, then due to these phenomena the walls will simply crack, and what’s even worse, they will corrode. In view of this, it is very important to be aware of how to make an armored belt. The types, purpose and method of installation of the armored belt will be discussed in this article.
There are 4 types of armored belt:
- grillage;
- basement;
- interfloor;
- under the Mauerlat.
Before starting work, you should prepare the following tools/materials:
- Fittings.
- Cement.
- Sand.
- Crushed stone.
- Wire for tying reinforcement.
- Boards.
- Self-tapping screws.
- Brick.
- Shovel.
- Crowbar/crowbar.
To ensure that all the work you perform is done with high quality, we suggest that you familiarize yourself with the techniques for manufacturing reinforced mesh/framework and formwork.
In order for the reinforced belt to be of high quality, and therefore the house to be reliable, you need to know how to properly make the reinforced mesh/frame. The connection of the reinforcement bars to each other is carried out using a knitting wire, and not a welding seam. This is due to the fact that during welding, the area near the seam being made overheats, which leads to a weakening of the strength of the reinforcement. But you can’t do without welding seams when making mesh. The middle and ends of the frame are welded, while the remaining connecting nodes are tied together.
The rods are fastened to fix the reinforcement in the required position when pouring concrete. For these purposes, thin wire is used; the strength of the mesh/frame does not depend on it.
For the manufacture of armored belts, only ribbed rods are used. Concrete clings to the ribs, which helps increase load-bearing capacity designs. Such a belt can work in tension.
To make a frame, take 2 wires 12 mm thick and 6 m long, while for transverse reinforcement you will need rods 10 mm thick. The transverse reinforcement should be welded in the center and edges. The rest of the rods are simply knitted. After making two meshes, hang them so that a gap is formed. Weld them from the edges and in the center. This way you will have a frame. There is no need to weld the frames to make the belt. They are laid with an overlap of 0.2–0.3 m.
Installation and fastening of formwork is carried out using several methods. To install wooden panels, you need to pass anchors through them and install plugs on them using electric welding. The purpose of these actions is to fix the formwork in such a way that it is not squeezed out under the weight of the concrete.
To secure the formwork when pouring interfloor armored belt A simpler method is often used. A screw with a diameter of 6 mm and a length of 10 cm should be fixed to the bottom of the shield. The distance between them is 0.7 m. So, attach wooden shield to the wall, drill a hole through it, insert a mushroom into it and hammer in a screw.
The hole in the shield should be slightly larger than 6 mm in diameter. This is necessary in order to easily install the fungus.
The upper part of the formwork is also secured with quick installation. But in this case, you should screw in a self-tapping screw, not a screw. So, make a hole in the face brick. Then drive the reinforcement into it. If the brick is solid, then the situation is simpler - just drive a nail/reinforcement into the vertical seam. Tighten the self-tapping screw and reinforcement with binding wire. The distance between fastening elements is 1–1.2 m. Such fastening is capable of withstanding the upcoming loads.
After the armored belt has hardened, the formwork can be removed using a crowbar/nail puller. In the warm season, concrete sets within a day. In this case, the dismantling of the formwork can be carried out the next day. During the cold season, this procedure is carried out a few days later.
Initially, you should determine the depth of the foundation. This parameter depends on the type of soil, the depth of its freezing, as well as the depth of groundwater. Then you should dig a trench around the perimeter of the future house. This can be done manually, which is long and tedious, or with the help of an excavator, which is quick and efficient, but entails additional costs.
After special equipment is used, the bottom and walls of the trench should be leveled to solid ground. The surface should be as hard and smooth as possible.
Now you need to form a sand cushion, the height of which should be 50–100 mm. If it is necessary to backfill sand more than 100 mm, it must be mixed with crushed stone. This activity may be necessary to level the bottom of the trench. Another way to level the bottom is to pour concrete.
After filling the sand cushion, it must be compacted. To complete the task faster, pour water on the sand.
Then the reinforcement should be laid. During construction in normal conditions you need to use reinforcement of 4–5 cores, the diameter of each rod should be 10–12 mm. It is important that when pouring the grillage for the foundation, the reinforcement does not touch the base. It must be recessed in concrete. Thus, the metal will be protected from corrosion. To achieve this, the reinforcing mesh should be raised above the sand cushion, placing brick halves under it.
If you are building a house on heaving soil or where the groundwater level is high, then the grillage should be made more durable. For this instead reinforcing mesh reinforcement cage should be used. He imagines 2 meshes consisting of 4 wires with a diameter of 12 mm. They should be laid below and above the armored belt. Granular slag is used as a base instead of a sand cushion. Its advantage over sand is that over time, granulated slag turns into concrete.
To make the mesh, a knitting wire is used rather than a welding seam.
For the grillage, M200 concrete should be used. To ensure that the filling height corresponds to the specified value, install a beacon in the trench - a metal peg equal in length to the height of the grillage. It will serve as your guide.
Before erecting walls, a basement reinforced belt should be poured onto the foundation. It must be poured along the perimeter of the building along external walls, but you can’t do this along the inner load-bearing walls. The base armored belt serves as additional reinforcement of the structure. If you have filled the grillage with high quality, then the plinth belt can be made less durable. The height of the armored belt is 20–40 cm, concrete M200 and higher is used. The thickness of two-core reinforcing bars is 10–12 mm. The reinforcement is laid in one layer.
If you need to strengthen the base belt, then use reinforcement of greater thickness or install more conductors. Another option is to lay the reinforced mesh in 2 layers.
The thickness of the basement and external walls is the same. It ranges from 510 to 610 mm. When pouring the base armored belt, you can do without formwork, replacing it with brickwork. To do this, you need to make half-brick masonry on both sides of the wall. You can fill the resulting void with concrete after placing reinforcement in it.
In the absence of a grillage, it is useless to make a base armored belt. Some craftsmen, having decided to save on the grillage, strengthen the base belt, using reinforcement of a larger diameter, which supposedly improves the load-bearing capacity of the house. In fact, such a decision is unreasonable.
The grillage is the foundation of the house, and the plinth belt is an addition or strengthening of the load-bearing capabilities of the reinforced belt for the foundation. Collaboration grillage and plinth belt guarantee a reliable foundation even on heaving soils and with high level occurrence of groundwater.
An armored belt must also be made between the wall and the floor slabs. It is poured along external walls with a height of 0.2 to 0.4 m. Interfloor armored belt allows you to save on door/window lintels. They can be made small and with a minimum of reinforcement. Thus, the load on the structure will be distributed evenly.
If an armored belt is installed on walls made of poorly load-bearing material, the load from the floor slabs will be distributed evenly along the entire length of the walls, which will have a beneficial effect on their strength characteristics.
Reinforcement of the interfloor belt is carried out with a mesh of ribbed reinforcing bars 10–12 mm thick in 2 cores. If the wall thickness varies between 510–610 mm, then double-sided formwork can be used brickwork, as for the base belt. But at the same time, backing bricks should be used for internal masonry, and facing bricks for external masonry. In this case, the armored belt will have a width of 260 mm. If the walls are thinner, the backing brick should be laid on edge or wooden formwork should be used instead, and with outside The facing brick is laid in the same way as in the previous case.
The armored belt can be poured under the Mauerlat only after the glue/mortar for masonry walls has hardened. The technology used to lay the reinforced belt on aerated concrete differs in the formwork design, but we will talk about this a little later. The production of wooden formwork is carried out according to a scheme already familiar to you. Concrete is prepared according to the following formula: 2.8 parts sand to 1 part cement and 4.8 parts crushed stone. Thus, you will get M400 concrete.
After filling, eliminate any remaining air bubbles in the mixture. To accomplish these tasks, use a construction vibrator or poke a rod into the liquid mass.
At monolithic device armored belt, you should follow the rules for attaching the Mauerlat. During the installation of the reinforcement frame, vertical sections should be removed from it to the height specified in the project. The reinforcement bars should rise above the reinforced belt by the thickness of the Mauerlat + 4 cm. It is necessary to make through holes, equal to the diameter of the reinforcement, and threads should be cut at its ends. Yes, you can do it reliable fastening, which will give you the opportunity to implement high-quality installation roofs of any configuration.
Aerated concrete is an alternative to brick, which has high thermal insulation qualities along with low cost. Aerated concrete blocks are inferior to brick in strength. If, when installing an armored belt on brick walls There is no need to pour concrete, since the reinforcement is laid during the laying process, but with aerated concrete things are different. How to make an armored belt on wooden formwork has already been discussed above, so in this subsection we will look at how to make a reinforced belt from U-shaped aerated concrete blocks D500. Although it is worth noting immediately that this technology is more expensive.
In this case, everything is extremely simple. Place the blocks on the wall as usual. Then reinforce their central part, and then fill it with concrete. Thus, the walls of your home will be more durable and reliable.
If you still have questions on the topic, then ask them to a specialist working on the site. If necessary, you can consult with our expert about filling the armored belt. Eat personal experience? Share it with us and our readers, write comments on the article.
Video
You can learn how to make an armored belt for a house made of aerated concrete from the video:
Concrete belt, reinforced with metal fittings, is one of the important structural elements of the walls of a house made of aerated concrete blocks. The strength of walls that receive vertical loads from interfloor ceilings and roofs and transfer them to the foundation of the building. The armored belt also additionally strengthens the structure of the house from deformation during soil movement.
Concrete itself is a material that has the highest compressive strength, while the reinforcement works well in tension. Therefore, the reinforced concrete armored belt is capable of carrying very large bending loads without any slightest deformation. At the same time, the gas-block walls located underneath will experience several times less load, since the armored belt distributes it evenly over them.
An armored belt is poured onto aerated concrete walls under the roof, for installation (support beams for rafters), under slabs and beams of interfloor floors, as well as for strengthening block, pile and column foundations.
Armobelt for the walls of a house made of aerated concrete
Often inexperienced, novice builders don’t even know what the walls are for one-story house should be filled reinforced concrete belt. And the need for its device lies in the following reasons:
Armored belt sizes
Monolithic is poured around the perimeter of the entire building, and its dimensions are tied to the width of the external and internal walls.
The height can be filled according to upper level aerated block or lower, but it is not recommended to raise it above 300 mm - it will be easy unjustified waste of material and increasing the load on the walls of the house.
The width of the armored belt for aerated concrete is made according to the width of the wall, but it may be a little narrower.
Concrete belt reinforcement
For reinforcement, metal or fiberglass reinforcement is used. Usually its cross-section does not exceed 12 mm. Most often, the reinforcement cage consists of four long rods that laid along the wall of the house. From them, using staples from reinforcement of a smaller cross-section, a square or rectangular frame. Long reinforcing bars, every 300 - 600 mm, are attached to the brackets with tying wire. It is not recommended to use welding to connect them in the frame because the metal at the point of penetration is weakened, and at the same time, corrosion may occur at this point.
The frame should not be allowed to come into contact with aerated concrete blocks. To do this, special plastic pads with a height of about 30 mm are placed under it. As a last resort, you can place separate pebbles of crushed stone.
Attention. To properly make a frame for a reinforced belt, it is recommended to use reinforcement only with a ribbed surface, which ensures rigid adhesion to concrete.
When can you do without an armored belt?
Pouring a reinforced belt to strengthen walls does not always make sense. Therefore, in order not to spend extra capital on purchasing materials, you should know in what cases you can do without a reinforced concrete belt:
- The foundation is located on solid rock.
- The walls of the house are built of brick.
It is also not necessary to pour a concrete belt over aerated concrete blocks if a wooden floor will rest on them. To unload the ceiling, under load-bearing beams floors, it will be enough to fill small supporting structures with concrete concrete platforms about 60 mm thick.
In other cases, when construction is carried out on peat bogs, clay, and other weak soils, it is necessary to make an armored belt. It is especially impossible to do without it when constructing walls made of aerated concrete, expanded clay and other large-cell blocks, which are fragile materials.
Gas blocks are practically incapable carry point loads and become covered with cracks at the slightest subsidence of the foundation or when the soil moves.
How to fill an armored belt with concrete correctly
When filling, the following rules must be observed:
- Concrete placement must be completed in one continuous duty cycle. For a high-quality reinforced concrete belt, partially dried layers of concrete mass are unacceptable.
- Air bubbles should not be allowed to remain in the concrete mass, which form pores and thereby reduce the strength of hardened concrete.
To prevent this from happening, freshly poured concrete must be compacted using an internal vibrator or a special attachment using a hammer drill. In extreme cases, it can be compacted with a tamper or a metal pin.
Types of belts and their functions
Reinforced concrete belts are poured to strengthen structures such as:
Sometimes when constructing small outbuildings used reinforced brick belt on aerated concrete walls. To do this, 4 or 5 rows are laid out on the walls, across its entire width. building bricks. Between the rows, in an armored belt made of bricks on walls made of aerated concrete, in the process of work, it is laid on mortar metal grid, welded from wire 4 - 5 mm thick with cells 30 - 40 mm. Floor beams or a wooden Mauerlat can be placed on top to secure the roof.
Reinforced armored belt on aerated concrete
For a reinforced belt, which is poured over aerated concrete blocks, it is used concrete mortar grade M 200. Load-bearing reinforcement with a cross-section of 12 mm is fastened in a frame with transverse square or rectangular clamps using knitting wire. Clamps are made from smooth reinforcement with a diameter of no more than 4-6 mm. The supporting reinforcement is overlapped with each other with an overlap of at least 150 mm and tied together with soft knitting wire.
The belt can be made without a three-dimensional frame of 4 reinforcing bars. Sometimes it's enough flat frame of two rods, which is assembled in almost the same way as a volumetric one. Only in this case, for transverse ligation, not clamps are used, but individual reinforcing bars.
The connected frame can be laid in wooden formwork, which is made from boards. Can also be used as formwork, aerated concrete blocks top row. But first you need to cut out the inside of them so that the block becomes something like a box without end walls. The blocks are stacked with the resulting shelves up, after which the frame is laid in them.
When laying the frame, you need to make sure that there is a small space of about 20 - 30 mm between the reinforcement and the formwork walls, as well as the lower blocks.
After bookmarking in reinforcement cage formwork, you can additionally make and attach to it the necessary embedded parts that will be needed to secure the Mauerlat or other elements from the house structure.
Separate reinforced belt under monolithic slab no overlap is done. The slab itself distributes almost all vertical loads evenly onto the walls, and at the same time it is the main stiffening rib for the house and connects almost all the walls of the building with each other, combining them into one spatial structure.
It would be ideal if it takes up the entire width of the wall. But this is usually done if on the facade side insulation will be installed, blocking the cold bridge that can form through concrete. But in the case when outside it is assumed only plaster finishing, its thickness will need to be reduced within 40 - 50 mm to lay polystyrene foam or other insulation.
To insulate the belt, you can also use thin (100 mm) partition blocks, which are installed and temporarily secured along the edge of the wall. A frame is laid between them and everything is filled with concrete. In this case, the partition blocks play the role of formwork and at the same time insulation.
Reinforced belt for wooden Mauerlat
Since aerated concrete blocks have a fragile porous structure, it will not be possible to firmly attach them to rafter system roofs of the house. Under the influence of wind, the fastenings will simply become loose over time and the roof may become deformed. And with a strong gusty wind, it can simply be blown away.
In addition, when the roof is loosened, when its fasteners are weakened, the upper rows of block masonry will also collapse over time. Therefore, a reinforced concrete belt is simply necessary for a strong connection between the roof and walls made of aerated concrete blocks.
The reinforced belt for mounting the Mauerlat can be smaller in width than its counterparts for the ceiling and foundation, since the vertical load on it is minimal. Therefore, to reinforce it, often to save money, a frame with two reinforcing bars is used.
To securely fasten the Mauerlat in the belt, even before pouring it, vertical anchors are installed bolts with external thread , which together with the frame are filled with concrete. In this case, the thread rises above the concrete by approximately 200 - 250 mm.
To firmly fix the Mauerlat, through holes are drilled in it, through which it is placed on the anchors, after which it is firmly pressed to the concrete with nuts.
Eventually— a properly made reinforced concrete belt can provide a house built from aerated concrete blocks with high strength and durable operation. At the same time, it will be able to protect walls from deformation and cracks, maintain the strength of the roof and extend the service life of the house by 3-4 times.
Mauerlat is wooden structure, through which the roof is attached to the walls of the house and on which the system of roof rafters is attached. Usually this is a wooden beam made of coniferous species. The timber of the timber must be at least second grade. Pine or larch is used for production.
The dimensions of the timber can be: 150x150mm; 150x100mm; 80x180mm; 100x100 mm; 200x200 mm.
Before fixing the wooden beam of the Mauerlat, it must be impregnated antiseptic. This will help prevent possible wood rot on the cinder block.
If you choose wood yourself, you need to take into account the knowledge passed down from generation to generation - a tree cut down in winter does not rot longer, and one cut down at the end of the month is better preserved than one cut down at the beginning of the month.
Wall mounting methods:
- fastening with anchor bolts;
- wire fastening;
- fastening with studs.
Attaching to a cinder block wall
Fastening with anchor bolts
When building a house from brick or cinder blocks, it is better to use the most reliable fastening of the Mauerlat - using anchor bolts secured in an armored belt.
The armored belt is a homemade reinforced concrete structure. It consists of a frame made of metal fittings and wires. This frame is immersed in a mixture of cement, sand and crushed stone. In other words, an armored belt is a reinforced concrete structure.
Here doubt may arise about the need to create an armored belt if the house is built from cinder blocks, which, in themselves, create enough robust construction. The thing is that the Mauerlat is attached to the walls of the building with anchor bolts, and attaching anchor bolts to blocks is strictly prohibited. This can cause even cinder blocks to crack and break.
The armored belt will increase the resistance of the building structure to current deforming loads: wind, house shrinkage, seasonal fluctuations of the foundation, point loads from slabs or beams. When pouring an armored belt, you need to know that it is poured as a single whole. It should not have any breaks.
Whether the Mauerlat will be able to fulfill its load-bearing function depends on how correctly the armored belt to which it is attached is made. The strength of the armored belt depends on how the formwork was installed during its creation.
Fastening the Mauerlat can begin after removing the formwork, when the concrete has completely hardened - this means 4 or 5 days after pouring the concrete.
You need to decide in advance how many anchors you will install to attach the Mauerlat to the cinder block walls. The number of anchors must be no less than the number of rafters that will be attached to the mauerlat. We must not forget that the location of the anchor bolts should not coincide with the location rafter legs. This will reduce the rigidity of the structure. It is advisable that the anchors be located in the middle between the rafters.
Very difficult to wall up anchor bolts into concrete so that they stand strictly vertically and at the same distance from each other. To do this, it is necessary to mark in advance the distance between the anchors, taking into account the location of the rafters and the fact that the anchors should be located at a distance of 0.8 to 1 meter. Metal pins- must protrude above the concrete surface by at least 20 cm.
Some builders attach anchors to pieces of rebar that protrude where the bolts are placed. Fastening occurs by welding.
In order to drill holes in the Mauerlat exactly in the place where the anchors will be located, you can use two methods:
- Take a board, secure it to the outer anchors and mark the location of future holes. Then transfer this marking to the Mauerlat;
- Place the mauerlat over the anchors and hit it with a sledgehammer. You will get a marking for drilling holes. They should be slightly smaller than the diameter of the bolt.
Before attaching the Mauerlat to the wall, you need to isolate the concrete surface from the wooden beam. For this insulation, two layers of roofing felt, polyethylene or other waterproofing material are used. The waterproofing material must not be damaged. The Mauerlat is put on the bolts and pressed as tightly as possible to the wall.
Fastening with wire
For this fastening method, steel wire with a cross-section of 4 to 6 mm is used. It is twisted several times and placed in the wall masonry at a distance of one cinder block from the level of the Mauerlat. The wire can be fixed to the reinforcement of the reinforcement belt - this will increase the strength of the connection between the wall and wooden beam. The length of the wire should be enough to pass through the holes in the beam or to completely encircle it and to tie the ends together. When using wire, two holes are drilled opposite each fastening at a height of 25 to 30 cm. The wire is threaded into these holes, tightened and secured, thereby pressing the Mauerlat to the wall.
Fastening with studs
Fastening the Mauerlat with construction pins is only possible if the house being built is small. Metal studs are L-shaped hardware, which are embedded in the masonry of the wall. The stud should be immersed in the wall by 45 cm and protrude above the wall and above the Mauerlat strung on it by 30 cm. The stud does not have to be embedded in the wall masonry. It can, like an anchor, be poured into concrete when constructing an armored belt. This will give the mount greater strength. The threads of the studs must be clean.