Installation of the roof on aerated concrete blocks without reinforced belt. How to properly attach the Mauerlat to an aerated concrete wall? What is a Mauerlat
One of the most important nuances technology for building a house from aerated concrete is the fastening of the Mauerlat. The characteristics of the blocks do not allow them to withstand high point loads; without taking structural measures, the walls will simply collapse. Correctly performed fastening involves laying an armored belt; it is not recommended to skip this stage. If it is impossible to organize it, the Mauerlat comes into direct contact with the wall and is fixed with wire, anchors, pins or dowels. The method is determined in advance; in the absence of experience, this type construction work It's better to leave it to specialists.
Possible fastening methods
Depending on the type of strapping scheme, one of two options for attaching the Mauerlat to aerated concrete is selected: pouring a monolithic reinforced concrete belt around the entire perimeter of the building or placing fixing elements directly into the masonry or blocks. The first method, in addition to ensuring maximum reliability, helps to redistribute loads, levels the walls and protects them from deformations, including shrinkage. The presence of an armored belt is mandatory when carrying out construction in areas with seismic activity, erecting houses made of aerated concrete over one floor, using heavy roofing materials, complex shape roofs.
Standard instructions for laying it include the following steps:
- Preparatory: calculation of fasteners and selection of the interval between them. The main guide is the layout of the rafters: when equal number The points of attachment to the Mauerlat should not coincide with the places where the studs are screwed.
- Laying U-shaped blocks on top of the last row around the entire perimeter of the aerated concrete wall. They act as formwork, the recommended width is from 25 cm.
- Assembly of a reinforcing frame from rods with a thickness of 10 mm. At this stage, it is planned to lay pins to fix the Mauerlat at intervals of no more than 1 m, strictly vertically, tied with wire to the main rows. Particular attention is paid to the corners; in these areas, metal rods are bent to a length no less than the width of the belt. Similar actions are repeated along the entire perimeter of load-bearing walls, including gables and partitions.
- Organization of an insulating layer made of compacted polystyrene foam. It is placed closer to the outer edge of the aerated concrete wall.
- Fill internal cavity concrete with a strength grade of at least M200, compaction, removal of excess and careful leveling of the top layer. Cover with polyethylene and standard moisture care during the first days.
You can begin the next stage of tying the Mauerlat to the aerated concrete walls in a week. Everyone is filmed formwork structures(they are used when pouring a monolithic reinforced concrete pad along the entire perimeter and width, this design is typical for brickwork, but is sometimes used for houses made of gas silicate). Next, 2 layers of waterproofing are laid or coated on top of the upper side in contact with the future Mauerlat; this stage cannot be skipped. Attachment points are marked on a wooden beam treated with antiseptics and fire retardants and well dried. The easiest way to do this is by placing it on the armored belt over the studs and hitting it with a sledgehammer; holes are drilled according to the diameter of the rods (at least 14 mm). After this, all that remains is to attach the Mauerlat to the aerated concrete wall and tighten it with nuts or washers.
The final stages of the work are difficult to complete on your own; at least 2 people will be required. Besides main walls The armored belt is mounted on any areas on which roof elements rest (for example, ridge posts or beds). If you have no experience, you should watch video instructions on the topic “how to properly attach the Mauerlat.” If you need to eliminate errors that occurred during the laying process, it is better to contact specialists, at least for advice. Installation of rafters is possible only after completion of all work on fixing the Mauerlat and checking the quality of connections.
How is the Mauerlat attached to the wall in the absence of an armored belt?
Laying a monolithic tape with your own hands is not always possible; in some cases, they resort to other methods of tying the timber. The easiest way is to lay steel wire 3-4 rows before the top between the blocks. Its length is selected taking into account the cross-section of the Mauerlat: when folded in half, it should be enough to girth and twist. The pitch depends on the distance between the rafter structures. This option is often used when attaching timber to a wall. one-story house from aerated concrete.
For light and small-sized buildings, the Mauerlat attachment on threaded rods made of galvanized or of stainless steel. They are installed in the masonry 1-2 rows before the top edge; the minimum permissible depth for recessing such products into a wall made of aerated concrete is 2 times the height of the block. Standard length studs - within 1 m, diameter - from 8 to 24 mm. If necessary, protruding areas are then cut off.
Fastening the Mauerlat beam with wooden dowels is possible both when laying an armored belt and without it. They are long corks treated with antiseptics and well dried. They are mounted into a wall made of aerated concrete closer to the upper edge and connected to the Mauerlat using brackets. Alternative option is their laying between the blocks, the number of pieces is not less than the number of rafters.
High reliability of fastening is ensured using anchors: mechanical or chemical. In the first case, the method consists of screwing expanding dowels with a cross-section within 12-14 mm into aerated concrete. The second is in the use of chemical anchors (capsule or in the form of a tube with compositions based on polymer resins). The minimum depth of the hole to be laid is 2 rows of masonry.
The main advantage of anchoring is the ability to secure the Mauerlat without complex organizational measures in the process of laying gas blocks; it is quite easy to do it yourself. However, the best results are observed with maximally immovable hardware, that is, either laid simultaneously with an armored belt, or fixed using chemical compounds (in the latter case, welding work near the joints is prohibited). The disadvantages of this method include its high cost: of all the technologies for fastening without an armored belt, anchoring will cost the most, and the more reliable it is, the higher the final costs will be.
Violations of the Mauerlat fastening technology when doing DIY work include:
- Lack of waterproofing layer between the beam and top part walls. Preference is given to modern bitumen-polymer mastics, budget option is roofing material, polyethylene film not suitable for these purposes due to low strength. The minimum number of waterproofing layers is 2.
- Planting a mauerlat that has not been treated with antiseptics (the contacting side remains unprotected) or the use of wet wood.
- Installing anchors or studs at an angle makes the connection unreliable.
- Incorrectly selected reinforcement for the frame, lack of overlaps (the recommended minimum if it is necessary to extend the rods is 20 cm), close contact of the metal to the walls of aerated concrete (plastic stands are well suited to provide the required 5 cm).
When using raw wood, the Mauerlat is fixed with a nut, the reliability of the fastenings is periodically checked, and if necessary, they are tightened. This operation is carried out at least once a year for 4-5 years, until the end of the shrinkage processes. A completely dry and established beam practically does not need tightening; its inspection is carried out for preventive purposes.
Private and public construction requires the use of structural elements of varying complexity. When constructing houses from aerated concrete, a special element is used - Mauerlat. Exists special technology, describing the fastening of the Mauerlat to aerated concrete without an armored belt. This construction method significantly increases the reliability and service life of the future structure.
Design Features
The technology for building houses from aerated concrete is being improved for objective reasons - there is demand for aerated concrete blocks growing every day. The peculiarities of constructing houses from this material allow for high-quality construction in the shortest possible time. House built from cellular concrete, has beneficial thermal insulation characteristics, and also has a relatively small structural mass.
Aerated concrete has a disadvantage associated with the difficulty of attaching structural elements to each other. The porous base of the walls is difficult to connect to the main frame, and builders have to look for additional solutions. Mauerlat is a structural element connecting the walls of a building and the roof. An armored belt made of reinforced concrete helps solve the problem, but some homeowners use the method of attaching the Mauerlat to aerated concrete without an armored belt.
The peculiarity of aerated concrete structures is that it is difficult for porous concrete to withstand the point pressure of pressing elements. Mauerlat represents an important structural element, performing the load function. Unlike the foundation, the Mauerlat carries the load exerted only by the roofing part of the building - the roof, the inside of the slope and the thermal insulation layers.
Working with a metal or wooden Mauerlat helps in redistributing pressure on the walls. Fastening the Mauerlat also facilitates installation work associated with the installation of rafter elements.
Calculation algorithm
Work on installing the desired material can be performed using the following modules:
- Wooden supports;
- Metallic profile.
The cross-section for wooden beams is selected within the format of 10 cm * 10 cm. If the roof has particularly large dimensions, then it is recommended to use modules bigger size(10 cm*15 cm, 15 cm*15 cm, 15 cm*20 cm). There is a certain proportion in accordance with which the Mauerlat is fastened for work - the thickness of the material should be equal to 2 thicknesses of the rafter supports.
The production of a mauerlat from logs is possible, but does not justify the effort expended - the cross-section of the log is difficult to adjust to the configuration of the rafter components. The characteristics of the wood chosen for the job must also be of a high standard. The Mauerlat is fastened using wood, which is tested for wear resistance and absence of mechanical damage.
High-quality wood is considered the best option hardwood, treated with special compounds. It is also possible to use a metal profile for roof fastening work. Carrying out such work is accompanied by the use of a channel or I-beam impregnated with anti-corrosion substances.
Basic values
A specialist installing a Mauerlat without an armored belt must carry out correct calculation main parameters. The following values are taken into account during operation:
- Built-up area;
- Type roofing system;
- Features of roofing material;
- Seismic activity of the zone;
- Climate influence.
There are various structural forms of the roof, but the most common is the gable roof. As an example, it is beneficial to make calculations for work on this type of roof. The volume of the Mauerlat is measured using the formula V=P*S, Where P– perimeter of the flooring, and S- section of timber or V= N/R, Where N is the mass of the beam, and R– wood density.
Fastening methods
Fastening the Mauerlat to aerated concrete without an armored belt can be carried out in accordance with several technologies. Work on fastening to aerated concrete blocks is carried out using special elements.
Chemical anchors
This method is based on the use of chemical resins with adhesive properties. Liquid dowel or other chemical paste perfectly connects the porous surface of aerated concrete and metal profiles. In small buildings, corners can be fixed using ties, brackets and screws. Anchoring increases the level of protection of the structure.
Working with chemical compounds involves the following list of actions:
- Filling the hole with adhesive;
- Fixation of the metal frame;
- Control of composition hardening.
It is noted that corners strengthened in this way are distinguished by great durability and long term operation (up to 50 years). It is prohibited to conduct welding work with fixed metal profiles, since chemical anchors are sensitive to high temperatures.
Studs for fastening
Construction studs are perfect for small-sized buildings, where the Mauerlat is fastened so that it serves as a reinforced belt.
Working with pins involves the following list of actions:
- Drilling holes at a distance of 1.5 m;
- Fixing the stud with cement;
- Installation of a waterproofing layer;
- Installation of the Mauerlat;
- Fastening the timber with forged brackets;
- Installing a roofing system on top of a structure.
Steel wire
Using steel wire of a certain thickness, you can achieve a similar result in installation work. Using this method involves the following sequence of actions:
- Embedding twisted wire into the walls of a building;
- Control correct position wires in aerated concrete;
- Control of free passage of wire through the beam;
- Calculation of the required number of components in accordance with the number of rafters.
Supporting rafters on walls made of small blocks of porous concrete can be done using special reinforced beams - brackets. The brackets are made of metal with an anti-corrosion coating. Fixation occurs using wire ties, self-tapping screws, plates and perforated tape.
When arranging a roof with one or more slopes, it becomes necessary to install rafter system. However, it is impossible to lay rafters directly on the walls - for this purpose they use a Mauerlat, which redistributes the load. If the walls of a building are constructed from such porous material like aerated concrete, it is not always possible to lay a reinforcing belt under the Mauerlat. In this article we will talk about how to secure the Mauerlat to aerated concrete without an armored belt using various methods, we will describe in detail the technology and subtleties of this process.
Why do you need a Mauerlat?
So, the Mauerlat is very important element structure, which takes the main weight of the rafter system and distributes it evenly over the entire plane of the load-bearing walls. As a rule, it is made of a material similar to rafters - most often wooden beams. However, a steel rafter system will require a Mauerlat made from an I-beam or channel.
The following materials are used to make the Mauerlat:
- Wooden beams with a cross section of 100x100 mm, 150x150 mm, and also 200x300 mm. In this case, you can take a hardwood tree that has undergone antiseptic treatment. The timber is laid around the perimeter of the building. The logs are joined using the locking method or using nails. Wooden frames for roofs they are most often erected in private construction.
- Rolled profiles - I-beams in the shape of the letter H or channels in the shape of the letter P are used somewhat less frequently. In this case, the height of steel profiles can vary between 7-12 cm.
Whatever material you choose, it is attached to the surface of the walls. There can be several ways to attach the Mauerlat to aerated concrete. After fixing this element, installation is carried out rafter legs. It is worth noting that the Mauerlat not only redistributes the load, but also prevents the rafter system from moving in the horizontal plane.
Since aerated concrete is a rather fragile material and does not tolerate increased loads, many craftsmen prefer to pour a reinforcing belt along the upper edge of the walls. At the same time, to reduce costs and labor costs, there are some methods for securing the Mauerlat without an armored belt. It is also worth knowing whether a Mauerlat is needed if there is an armored belt, what the advantages and disadvantages are.
Please note that there must be at least 30-50 cm from the ceiling to the top edge of the mauerlat so that the space under the roof can be well ventilated and access to load-bearing structures roofs for maintenance and repair.
Methods of fastening to aerated concrete
It is worth noting that laying the Mauerlat on aerated concrete is much more difficult than, say, on a brick wall. Usually it is laid at a distance of 5 cm from the outer edge of the wall.
The following elements can be used to lay and fix the Mauerlat:
- steel wire;
- anchor bolts;
- chemical anchors;
- steel studs.
Fixing the Mauerlat on a reinforcing belt or on brick wall performed using anchor bolts.
After the beam is installed, the rafter leg is pulled to it and wound with twisted steel wire with a cross-section of 3 mm. 6 cm below the beam you need to install a short piece on which the rest of the wire will be fixed. Alternatively, the wire can be wrapped around the floor slabs for a secure fixation.
When it comes to the roof complex design, then it is recommended to fasten the Mauerlat beam to aerated concrete using a belt made of reinforced concrete. It will provide not only greater reliability of the structure, but will also allow the load to be evenly distributed.
The Mauerlat bars are secured to each other using an oblique cut and then secured with nails or bolts. Staples or steel plates attach corner connections additional rigidity.
Fixing the Mauerlat using wire
Before attaching the Mauerlat to aerated concrete using steel wire, it must first be fixed in the thickness of the wall. This should be done while laying the last rows of gas blocks - the wire is placed under them.
The installation technique in this way looks like this:
- A couple of rows before the end of the masonry, a twisted wire of several thinner wires with a cross-section of 6 mm is placed between the blocks.
- In this case, the central piece of wire will be placed in the thickness of the masonry, and the ends will hang down on both sides of the masonry. The length of the ends is made such that they are enough to wrap freely around the beam.
- There should be so many pieces of wire that it is enough to tie all the rafter legs.
How to secure with studs
It would be advisable to attach the Mauerlat to aerated concrete without an armored belt on studs only in cases where it is planned to use lightweight roofing materials for the ceiling in small houses. Therefore, the expected load on the walls will be small.
In addition, in this situation, the Mauerlat beam itself will serve as an armored belt. Although there are conflicting opinions regarding this type of installation of a Mauerlat on aerated concrete, practice shows that it has a right to life. This technique ensures a sufficient level of reliability and stability of roofing structures.
To work you will need the following components:
- metal studs SRT-12, which are also called “dovetail”;
- timber beam with a cross section of 20x30 cm - although the thickness depends on the size of the constructed wall of the building.
The sequence of work for laying the Mauerlat on aerated concrete without an armored belt looks like this:
- Along the entire length load-bearing wall in its upper part, recesses are drilled at a distance of 100-150 cm.
- Pins for the Mauerlat are placed in the finished holes and secured with non-shrink mortar or cement laitance.
- Waterproofing from a double layer of roofing felt is laid on the block wall. At the locations of the pins, holes are pierced in the material so that it tightly covers the surface of the metal. This stage helps protect the wood from rotting due to moisture.
- Next, recesses are drilled in the Mauerlat along the diameter of the studs with a pitch that coincides with their location.
- Now the mauerlat beam is put on the studs and secured with nuts and washers.
- After installing the beams, the abutting end parts are tightened with metal staples.
- Next, the rafter legs are installed directly.
The process of attaching the roof to aerated concrete will look somewhat different if the studs are mounted into a reinforcing belt.
The sequence of actions is as follows:
- Before pouring cement mixture Studs are installed in the formwork under the armored belt in increments of up to 1 m.
- They are fixed to the frame with knitting wire or plastic ties.
- Align the location of the studs along all axes.
- The formwork with reinforcement and studs is filled with a cement composition.
- After the reinforcing belt has completely hardened, the Mauerlat beam is placed on the protruding studs and tightened with nuts.
Application of chemical anchors
By chemical anchor is meant a liquid injection mass made on the basis polymer resin, which quickly hardens and firmly fixes the metal rods in the thickness of the Mauerlat.
The advantage of this material is the absence of bursting stress, so fragile aerated concrete does not collapse. If mechanical anchors fix parts by expanding the dowel, then adhesive composition chemical anchor fills the pores of aerated concrete and holds the rod motionless.
The process of attaching liquid dowels looks like this:
- A recess for the anchor is drilled in the gas block. The size of the recess should be larger than for a regular anchor bolt.
- Remove dust and debris from the hole, for example, with a vacuum cleaner.
- The adhesive composition is poured into the hole.
- Next, a threaded metal rod is inserted into the glue - an M 12-14 pin or a piece of reinforcement.
- Complete crystallization polymer composition occurs in 1/3 hour if the ambient temperature is above 20 ℃.
- Once the glue hardens, the pin will be securely fixed. It is noteworthy that such fasteners are stronger than mechanical ones.
Installing a roof Mauerlat on a wall made of aerated concrete using liquid dowels has a number of undoubted advantages:
- The fastening does not lose strength for more than 50 years.
- Due to the polymer structure of the glue, this method of fixation is widely used at the edges of walls, where there is a risk of the gas block splitting.
- The chemical anchor has good chemical resistance.
- Even wet weather and wet surface joined elements does not interfere with the installation of these fasteners.
- The installation of the roof mauerlat on aerated concrete blocks can be carried out without pouring an armored belt, since the reliability of fastening a chemical anchor is much higher than that of a mechanical one.
- Chemical composition The anchor is ideally combined with the porous structure of aerated blocks.
- To install liquid dowels, holes of a shallower depth are required than in the case of mechanical anchors - there the depth is 2-3 rows.
However, welding work cannot be carried out on anchors installed using this method - overheating metal rod will lead to disruptions in the polymer structure of the material, causing it to lose strength.
Fastening on mechanical anchors without armored belt
Finally, the last way to attach the Mauerlat to aerated concrete is the use of traditional mechanical anchor bolts.
The anchor consists of:
- internal steel rod with applied thread;
- outer casing - the spacer part of the mechanism.
The principle of operation of the anchor is the gradual deformation of the outer body as the nut on the bolt is tightened. In this way, the bolt is firmly fixed in the drilled hole.
Installation of anchors occurs as follows:
- Along the last row of blocks, beams are laid out along the walls.
- Holes for mounting bolts are made along the entire length of the beam in 1 m increments. Please ensure that the anchors are placed at the corners of the building and at the junction of two pieces of timber.
- Using a special drill, a hole is made through the laid Mauerlat in the gas block to the depth of the anchor. In this case, the depth of the hole should be no less than the thickness of 2-3 rows of masonry.
- An anchor bolt is inserted into the hole made. It is advisable to use products with a length of at least 50 cm and thread M 12-14.
- Finally, put a washer on the bolt and tighten the nut as tightly as possible. As a result of compression, the anchor body contracts and expands the material. So the bolt is securely fastened into the thickness of the wall.
For a user uninitiated in capital construction, it is unlikely that it will be known what a Mauerlat is, what role it plays in the construction of the structure, and so on. Therefore, the question of how the Mauerlat is attached to aerated concrete generally causes misunderstanding.
However, the use of such technology is a relevant and very effective solution. With its help, you can solve a number of significant problems that can reduce the durability and strength of the structure.
It is also necessary to mention more economical option implementation of the specified fastening method. If it is necessary to fasten the Mauerlat to aerated concrete without an armored belt, then in this case it is not a continuous armored belt that is poured, but concrete pads are made in the right places. This type of fastening for foam blocks is also quite reliable.
2.3 Metal studs
In the presence of small house, as well as a slight roof pressure, to fasten the cinder block walls with the Mauerlat beam, you can use a lightweight method - metal pins embedded in the wall. These are steel fasteners in the form of bolts with a base in the form of a square with sides more than 5 cm.
If, when laying cinder blocks, studs are embedded in the wall, they must be installed one or two rows before the top edge. The length of the pin should be sufficient to pass through the beam.
Subsequent commit similar to fastening a Mauerlat with a cinder block using anchor bolts.
2.4 Waterproofing during installation
Having decided on the method of fastening, it is necessary to calculate the fastening elements and their location. If it is necessary to fix the Mauerlat to the gas block without an armored belt, then the first option is suitable - steel wire.
Attaching the Mauerlat to aerated concrete is quite simple. Careful preparation of all components plays a primary role: wooden beams, fastening elements, reinforcement cage, reliable waterproofing. Let's look at the order of work.
Attaching the Mauerlat to aerated concrete
Before directly attaching the Mauerlat, you should prepare the base. Reinforcing belt – required condition when arranging the roof, if the walls are made of aerated concrete or any similar material.
The reinforced concrete strapping belt prevents the pushing of aerated concrete blocks and allows the dynamic and static forces coming from the roof to be evenly distributed completely over the wall area.
Arrangement of a reinforcing belt
The minimum size of the concrete tape is 200x150 m. It is attached with inner surface walls.
Installation steps:
- construct formwork around the perimeter of the house. Pediments must be treated;
- u-shaped blocks create a reinforced concrete belt;
- A frame is assembled from reinforcement 10 mm thick. The reinforcement should protrude by 4 cm;
- To rigidly fasten the Mauerlt to the aerated concrete, threaded studs are installed at intervals of 1 m. Their diameter is 14mm;
- the blocks are filled with concrete grade M-200;
- After a week, you can remove parts of the formwork and attach the Mauerlat.
Important: at the stage of preparation for the start of work, builders are required to calculate the number of studs and the future distance between them. Attachment points wooden structure to the rafters and the connection points with the reinforcing belt should be located in different places. Check that the number of rafter legs and studs is the same.
Preparing a wooden structure
The beams are treated before installation antiseptics, preventing wood rotting. A log or beam with a cross-section of 100x100 mm or 150x150 mm is wrapped in waterproofing material. Bitumen-polymer is suitable for this purpose. waterproofing material. Ruberoid is not used.
High-quality materials will allow you to create robust construction. The tree should not have knots or cracks. Humidity must be appropriate building regulations.
If the developer uses “raw” wood, it should be possible adjust the anchor nut.
This operation is performed once a year for 5 years. During this period, intensive shrinkage of wet wood occurs. As the beams dry, you will have to tighten the nut less and less.
In this photo you can clearly see one of the ways to attach the Mauerlat to aerated concrete walls.
How to properly attach the Mauerlat to aerated concrete?
Use an anchor with a washer and nut. Anchor shape: T- and L-shaped. Thread: M12 or M14. According to international building codes, in earthquake-prone areas the distance between adjacent anchors should not exceed 1 - 1.2 m.
Mechanical type of fastener
Procedure:
- dowels are inserted into the prepared holes;
- screw in the fastening element;
- the teeth of the harpoon are firmly pressed into the aerated concrete;
- the surface expands;
- the structure is securely fixed.
Great option Installing a Mauerlat on aerated concrete has only one drawback - high cost. 1 anchor and a special dowel with a harpoon costs more than 3 thousand rubles.
Another video on how to attach the Mauerlat to aerated concrete.
Mauerlat installation
Another method is used to firmly secure the Mauerlat in aerated concrete walls Oh. Will need capsule with chemical . Its cost is much lower - 150 rubles. for a unit.
Reliable fixation of the structure is achieved through the penetration of chemicals into the pores of the material. Additionally concrete surface receives heat and waterproofing.
Final stage
After installing the Mauerlat on aerated concrete, proceed to installation truss structure
. There are two ways.
First option
- the boards are cut to 1/3 of the board depth;
- nails and metal corners will allow you to securely fasten the rafters;
- nails (2 pcs.) are hammered crosswise from the sides;
- an additional nail is driven in from above;
- The fastening angles finally secure the joint.
Second option
- cutting is not done in the rafters;
- a special support block is hemmed from below, resting on the Mauerlat;
- nails are driven in as in the first option.
The support beam has a length of 1 m. The second option is suitable for rafters that have a low height.
Fastening the tie beam can only be done after accurate calculations and preparation quality materials. Purchasing bars of poor quality from high humidity may lead to damage to the strength of the structure.
To attach the Mauerlat to an aerated concrete wall, use anchors with special dowels or chemical method installations. Be sure to follow thermal insulation of a reinforcing belt made of extruded polystyrene foam.
Compliance with the requirements will allow you to securely fasten the Mauerlat and create a strong rafter structure.
