The question arose about attaching the Mauerlat board to the wall. Yesterday I got the idea to drill holes vertically in finished wall to a height of 3 blocks (750 mm), take reinforcement for 10, pour mortar into the holes and drown the reinforcement in them, and weld studs to the top of the reinforcement, and so on every meter. The question is: will such a unique anchor hold it? It looks very tempting and technologically advanced...
Is an armored belt needed on the Mauerlat?
A reinforced concrete armored belt should be placed on top of the wall for seismic resistance. And studs are inserted into it to secure the Mauerlat.My house is also made of gas silicate blocks, the walls are 30 cm thick, I made an armored belt 20 by 20 cm, and another 10 cm of block so that there is no cold bridge.
The weight of the armored belt is quite sufficient. And it’s not just laid on top of the wall, but poured directly onto the wall, i.e. cemented to the top row of the wall. Those. As a result, the weight of the armored belt + the weight of the top row will be more than your three rows of blocks.
And the armored belt at the same time solves another problem - it distributes the weight of the ceiling beams. Beams cannot be rested directly on blocks.
***I plan to fasten the rafters and beams to the mauerlat using screws and metal corners - there are a lot of different ones on sale now. wire is somehow rude and unaesthetic.
That’s how I attached it, but I couldn’t find ready-made corners, I sawed it myself from a regular 50x50 corner, drilled holes, and used screws...
Dual use of materials
50 boards for straps and ceiling beams, and made forests out of them.
Yes, there is a board, but I’m too lazy to fence... There are 2 and a half rows left... They gave me rental sawhorses welded from rebar, so I use them... I’m just too lazy to move sometimes!
And what, there is no basement or attic in the house and there won’t be?
I have a base 1 m above the ground, + walls 3 m, and + in the attic around the entire perimeter 1.2 m. That is. full-fledged forests were needed.
And you still need to fill the armored belt around the entire perimeter...
So that the roof doesn't blow off
Regarding “so that the roof is not blown off by the wind,” there is another technique - the straps are tied with good wire to the crutches driven into the third row of walls from the top. Without such a wire connection, it is necessary to solve the problem of firmly attaching the straps to the Mauerlat.
Raise the walls another six blocks and create an attic
If yes, then it’s not too late for you to raise 6 more rows of blocks and very inexpensively double the area of the house using a full-size attic. This is exactly how I did it. Moreover, it is not necessary to finish the attic right away; you can leave it for later, as a spare floor, when you have the money and desire for it.
Construction Chronicle
seal
waterproofing
Mauerlat, impregnated with fire-bioprotection and tightened with studs - I will attach beams and rafters to it.
Opinion 1:
On my house the mauerlat is mounted, with the edge close to the outer wall... And will you let it out like a strap, placing the mauerlat against the inner wall?
How will you let the straps out, placing the Mauerlat against the inner wall? The straps will be attached to the beams, the beams will stick out from the outside of the house.
Why weren’t the studs embedded in the concrete of the reinforced belt in the center and placed at the very edge of the concrete?
The studs are welded to the reinforcement at 12, and it sits on the glue in a hole 75 cm deep (3 blocks). I think there is no way to turn it out - I added additional cement to the glue.
Question:
why not put the beams on the belt?
Answer:
What to fasten it with? And the Mauerlat acts as a load distributor over the entire area of the wall... something like this.
Opinion:
Mauerlat close to the outer wall, and attach the straps to it.
Answer:
I don’t think this is good. We look at the loads from the rafters - the rafters tend to stretch the house, that’s why they rest on a beam, which takes the load down and to the side... If you lean it on the wall, you can break the wall in winter with snow - there were already precedents...
But if you install a central purlin, the snow pressure will act differently:
Accordingly, the load inside will be held by the partitions.
Load distribution
Then the load will be on the supporting surface, otherwise - as in the photo - the entire load will be on the fastening and it will simply turn out if you add screws, but without screws it will just be loose. And the beam and rafters can simply split.
Truss placement
It would be better to connect the farms like this:
I intentionally left gaps so that it would be clear how to connect the elements of the truss. It is better to place the rafter leg on top, as shown in my drawing, and not on the side, as in your photo.
Opinion about straps
My straps are attached to the mauerlat and rest on it with a sawed-off piece, then going out - but approximately in the middle of the straps in height, there is a tightening, i.e. a horizontal board that connects opposite rafters to each other and prevents them from moving apart. And the Mauerlat lies on a full-fledged 20*20 armored belt with 4 reinforcement bars inside, you can’t squeeze it out with snow...
But in the first house, it was done like this: a mauerlat, ceiling beams on it, another board across the beams on them, and the straps rest on this top board. Those. almost like in your drawing, only one more board has been added across the top.
Corners and strips for fastening rafters
I bought a gentleman’s set and had to run around the market, but it cost about 3 thousand rubles in total for hardware for the entire roof; I saved a lot.
I laid out the rafters and the beam on the ground, sawed everything, twisted it, then untwisted it - now half the beams and rafters have become templates, according to which I sawed the blanks, with drilled holes - just screw them on the roof, no adjustments, everything should match. I started installing the beams, by the evening I screwed half of them ! I'll try to install the rafters tomorrow. Something quickly...
In the places where I indicated with arrows, fasten with self-tapping screws, otherwise the strap will slide!
The joint must be insulated and insulation must also be placed under the beams, otherwise the heat will escape, as in the photo:
The first rafter went up this evening!
And yet I would connect the rafters to the beam like this:
By slings
There will be vertical supports - so I think everything is fine...
Why spend money on wind and moisture insulation?
Yes for the future.
And don’t forget to nail the rear rails on top of the film!
I want to stretch the film over the bare rafters, then lathing and ondulin, so as not to hit the extra slats.
So I thought, maybe I could use long screws to tighten it up additionally after adjusting the straps?
it might crack... I’d rather cut a strip of tin... it could be doubled for strength and I’d tighten the sides with short screws... it would be much stronger
But the weight of the roof + the weight of wet snow will not withstand this method of joining.
I think it's easy! I have rafters 150 tons by 50 and a beam 180 by 50 - the margin is higher than the roof - with this section they make houses 10 by 10 and everything holds together, and it’s nailed down at random - I saw it myself
They make 10 by 10 houses with this cross-section and everything stays together, nailed together haphazardly - I saw it myself
And you didn’t look closely, the rafters on the mauerlat/beams are there on top, or stuck to the side like yours, i.e. Is there a risk of sliding down under load?
It is necessary that the rafter is at least a third of its thickness, standing firmly on the mauerlat/beam, so that it does not have the opportunity to slide even a centimeter.
Unfortunately, your method of fastening does not have the necessary rigidity...
Maybe you can change the attachment point of the rafters to the beams?
Or at least put vertical supports from the beam to the rafter, about 1 meter from the edge (these supports will also serve as the frame for the side wall of the attic), and make a groove in the rafter under this support - so that the rafter rests rigidly on it?
Saving on sheathing
Builder: I want to stretch the film over the bare rafters, then the sheathing and ondulin, so as not to hit the extra slats
And the sheathing will touch the film, but this is not permissible - the vent must remain. gap!
Strengthening the buckley-rafter assembly
I strengthened the connection beam-rafter with huge screws and self-tapping screws 200 mm long - it holds tightly. The frame is almost ready for film - I bought Ondutis A 100 membrane, tomorrow I will start covering the film. They promise to deliver Ondulin tomorrow evening - I bought 70 sheets according to the calculation using a special program http:// ondulineroof
Ondulin was purchased at a price of 375 rubles per sheet from Lera Merlin (nails are included, but I’m inclined to use self-tapping screws)
Rafters
I advise you to tighten the straps with a crossbar like the letter “A”, at least from an inch, approximately between the third sheathing boards from the top.
Don't forget the tree - organic material. It changes throughout “life”. It will dry out in the heat and expand in high humidity. Any very strong fastening will become loose over time.
I think you are building a house for a long time?
Why not cover it with iron?
I don’t like iron - it rattles in the rain, snow falls, and it rusts quite badly, I won’t say anything about installation, I have to hire a team. I’ll install Ondulin myself... And it’s no worse, as practice shows. Regarding maintainability, Ondulin is easier replace it rather than fuss with metal. In general, this is my conscious choice, I made it even before the house was built.
Roof sheathing
I finally started installing the roof after all sorts of minor delays - installing the gutter holders and so on. Today, in half a day I covered half the roof with film and sheathing, tomorrow I will continue. I ordered a crown for the top of the roof from the roofing center, I'm waiting. Something with the windows is a bummer - today is the deadline according to the contract - I called back, they said they would call back and keep quiet - tomorrow I will start demanding them.
Ondulin - is it worth it?
They said there was a super hailstorm, all the metal was twisted, at least something happened to the ondulin...
I covered the roof with foil... I'm waiting for the ridge on the roof when they do it, I intend to start covering it from above, but practice will tell... However, it's scary to climb on top! I've had enough fears...
Ventilation
Sergey! Don’t forget to cut the film along the ridge for ventilation, you understand!
Answer:
Understood nothing! This is not in the instructions for my membrane! I don’t have a film, but a vapor-permeable membrane - I tried it, you can even breathe through it, but as the night rain showed, it doesn’t allow water to pass through! In my opinion, there is no point in cutting - it already “breathes”
Attic floor
Well, this kind of floor would be in the attic - almost perfect... I'll cover it with a glossy yacht varnish - you'll fall in love... It's still modern batten this is a thing! It’s a pity you can’t lay beds in the house - heated floors won’t work
Today I wanted to take some photos of the views of the house - I finally finished lining the roof! But the battery in the phone ran out, so I only got the first photo... I'll continue tomorrow.
Well, today I managed to take a photo... .
Tell me, what is the pitch of the studs for maluart?
I don’t remember, I drilled about a meter later... Then be sure to use a vacuum cleaner with a plastic tube to remove the dust. Then he took glue and cement for strength, diluted it thinner and poured it into the holes, into the reinforcement with 15-inch studs welded at the ends. That's how it all was
Do-it-yourself aerated block house
Foundation
Material for building a house
As a rule, a continuous reinforced 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 attach the Mauerlat to aerated concrete without an armored belt. Let's see how possible this is, and whether it is worth resorting to such a solution at all.
A few words about the importance of the Mauerlat
What is a Mauerlat and why is it needed? To a person inexperienced in matters of construction, this tricky word often means nothing at all. Meanwhile, we're talking about about one of the most important load-bearing parts of a building structure.
Probably everyone knows what a foundation is. So, in terms of its functionality, the Mauerlat can be compared with a foundation strip. True, it is responsible for the loads transmitted from the entire building as a whole, and the Mauerlat is only responsible for those that are formed during the operation of the entire roof structure - rafter system, roofing covering, insulating “pie”, internal lining stingrays (if any), etc.
And the loads here can be considerable, and what is most dangerous is to have an expansive direction perpendicular to the surfaces of the walls, that is, to work towards their destruction. It's all about the angles of the roof slopes - this is what gives such a decomposition of the vectors of application of forces, both from the gravity of the roof structure itself, and from external loads - snow and wind.
Such bursting point loads transmitted from rafter legs are especially dangerous for walls made of piece material - brick or masonry blocks (which includes aerated concrete). This means that it is necessary to distribute the resulting load as evenly as possible along the entire length of the wall. And, again, by analogy with the foundation tape, a powerful wooden beam that rests tightly along its entire length against the end of the wall can cope with this.
The second remarkable quality of the Mauerlat is its significant relief installation work when installing the rafter system. Agree that attaching each rafter leg to a main wall is much more difficult than, as they say, “tree to tree.” The presence of a Mauerlat opens up very wide possibilities for using various connection schemes, from “blind” to moving, using a variety of fasteners.
A wooden beam with a cross-section of 100×100 mm and higher is usually used as a Mauerlat (as a rule, depending on the massiveness of the roof structure, another 100×150, 150×150, 150×200 mm is chosen). Very often they rely on an unspoken, in principle, but effective rule - the thickness of the mauerlat should be at least twice the thickness of the rafter legs.
Width - depending on the thickness of the wall on which it is installed. At the same time, they try to position the beam so that it is not flush with the surface of the wall, either outside or inside. This will make it easier to protect the wood from negative impacts. external environment, carry out insulation of this rather complex unit in terms of ensuring normal thermal insulation. This rule is not mandatory, but if you read the advice of the masters, they almost unanimously advise leaving at least 50 mm from the edge on each side.
It is possible to make a Mauerlat from logs, but this solution does not seem optimal - the operations of attaching to the wall, and then inserting rafter legs, will become much more complicated and, accordingly, will require increased skills in carpentry.
It is clear that due to the high responsibility of this element of the roof structure, for such purposes they try to choose first-class dried wood that does not have curvatures, pronounced knots, cracks, signs of biological decomposition, and other defects.
For Mauerlat, selected hardwood is generally recommended. But finding such material is not easy, so high-quality pine is most often used, but only subjecting it to a very picky choice: saving on quality in in this case– is completely unacceptable.
By the way, the Mauerlat may not be made of wood. For example, if you plan to create a rafter system from prefabricated or welded metal trusses, then a steel beam will be used as a Mauerlat - 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 a Mauerlat is abandoned when the walls are built from a durable material that is resistant to point and thrust loads (for example, concrete), and the roof design involves fastening the rafters to the external 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 mounting on the wall should not cause any concern. With concrete, stone, and brick walls it is simpler, since there are many ways to securely fix the beam at the end of the wall. For example, when laying ceramic or sand-lime brick Bookmarks are made from wooden blocks. This makes it possible to then use ordinary steel brackets to fasten the Mauerlat. But making such fillings with aerated concrete is an absolutely futile task; you don’t even have to try, since no reliability will be ensured. We have to look for other methods, which will be discussed later in the article.
On walls made of aerated concrete, it is recommended to make the Mauerlat in a “closed pattern”, that is, in the form of a frame that completely encircles the entire perimeter of the building - this way, maximum structural reliability is achieved. However, this is not always possible - for example, in the case when pediments are laid out from the same foam blocks. This means that the more securely the timber should be fastened to the end of the wall.
How is a gable rafter system calculated?
In the course of the presentation, we have already once referred the reader to the size of the rafter leg - the cross-section of the Mauerlat depends to a certain extent on this. But, taking into account the steepness angles and all the resulting loads - read in the special publication of our portal.
How can you attach a Mauerlat beam to a gas silicate wall without an armored belt?
First of all, a builder who is faced with a similar problem must clearly answer the question for himself - “Do I really not have the opportunity 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 disadvantages. And besides, the very possibility of installing a Mauerlat without an armored belt is quite doubtful, and is accepted with many reservations.
No matter how much you search, it is unlikely that you will be able to find clear criteria when experts clearly say - yes, you can do without a concrete reinforced belt on this gas silicate wall. There are only a lot of “ifs” under which, it seems, one can hope for the success of such an installation.
Prices for aerated concrete
aerated concrete
- If the house or outbuilding is small (alas, there are no evaluation criteria).
- If the roof has a not too complex and heavy structure (let’s assume that we are talking about simple ones made of, for example, corrugated sheets or metal tiles - all the rest roofing materials, together with its sheathing, will be heavier).
- If the climatic conditions of the construction region do not require a large snow load and wind pressure (and where is the guarantee that a weather anomaly will not occur?).
- If the design of the rafter system minimizes thrust loads. This can be provided by:
— Using hanging stops, rigidly tightened with horizontal ties.
- Using layered rafters, with mandatory support at the point of the ridge connection, if at the point of connection of the rafter legs with each other on the ridge there is a hinged connection, and the attachment point to the power plate involves the use of movable, sliding connections.
In a word, the list of conditions for trying to do without an armored belt (and then without complete confidence in success) is quite large. And you probably need to think ten times before choosing this particular path.
However, the Internet offers several methods for installing Mauerlat timber directly on a gas silicate wall without pouring an armored belt. Let's try to understand them.
Fastening the Mauerlat with wire
One of the simplest methods, which is often used when constructing 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 wires in a bundle) are laid between the rows, so that they look out from both the outside and the inside of the wall. The length of the release of these “braids” is made such that it ensures coverage of the Mauerlat timber installed at the end of the masonry and allows for trouble-free twisting and tightening of the wire loop. The spacing of such support bookmarks is usually chosen equal to the spacing of the rafters, so that the Mauerlat fastening points are located between adjacent rafter pairs.
When the wall is ready, it is laid on its end. Then a beam is installed on top, leveled, and then a wire loop is created and tightened. Tightening is usually carried out using a crowbar (mount), ensuring that the timber is pressed as tightly as possible against the wall.
It would seem that this is the simplest solution. However, take a closer look: all the examples shown are only on a brick wall. They write that this method works quite well with gas silicate blocks, only the laying of wire “braids” is carried out approximately two rows before the end of the laying.
They write, but not a single reliable proof of the reliability of this method with gas silicate walls could be found on the Internet.
According to personal feelings, will the wire work under heavy loads, and even more so under possible vibration, for example, in strong winds? hacksaw blade", gradually biting into the gas silicate block (which can be sawed hand hacksaw)? After all, this is both 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 and simple...
Fastening timber using anchors or dowels
It would seem that this is the simplest and most reliable method, tested by practice and time. Everything is true, but only if we are not talking about gas silicate. The increased fragility of this material may well present a surprise when, when tightening an anchor or screwing in a dowel, a crack or even a chip forms.
Of course, nowadays you can find on sale a considerable assortment of fasteners designed specifically for aerated concrete walls. But, you see, it’s one thing to fasten furniture, interior items or even a frame for wall insulation - and a completely different thing is a powerful one, which becomes the basis for the entire roof structure.
Considering that the holding properties of gas silicate are low, you will have to purchase anchors maximum length- about 300÷500 mm, so that, taking into account the thickness of the Mauerlat beam, it is possible to “catch” more or less reliably to the wall. But the cost of such long, powerful anchors is considerable, so this also needs to be kept in mind.
The work of installing the Mauerlat on the anchors is carried out approximately in the following sequence:
| Illustration | |
|---|---|
 | First of all, it is necessary to ensure reliable waterproofing between the gas silicate and the timber being laid. Otherwise, a source of dampness and, as a result, biological decomposition will inevitably appear at the point of contact between wood and other building materials. |
 | A strip of high-quality roofing material is quite suitable for a waterproofing barrier - it is laid so that it completely covers the entire end of the wall. If it comes in a little on the sides, it’s not a big deal, since it’s easy to cut it off later. The strip can be laid dry, that is, without the use of bitumen mastic. |
 | After this, the mauerlat is laid on the end of the wall. In this example, a high-quality board 50x150 mm is used for it, which, by the way, looks a little thin in terms of thickness. But this does not change the principle of fastening. |
 | The timber is laid exactly in its place, as provided for by the project, and leveled. |
 | The necessary markings are carried out. In principle, in this case it comes down to marking the areas for installing the rafter legs - then the anchors for fastening the Mauerlat can be placed between them - and there will be no mutual interference. |
 | The location for attaching the rafter leg is marked. The anchors can be positioned arbitrarily, repeating the pitch of the rafters. |
 | Here it is, the anchor bolt. Let’s make a reservation right away - in this example, an armored belt is poured on top of the gas silicate wall, so the master uses relatively small anchors, 12 mm in diameter and 150 mm in length. In mature concrete, such fastening will provide the required reliability. But if there is no armored belt, you will have to install the longest possible fastener - up to half a meter. |
 | Next, a feather-shaped wood drill (in this case with a diameter of 12 mm) is installed in the drill, and the mauerlat is drilled through holes, right 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 channel. |
 | After this, a hammer drill with a 12mm drill is used. A channel for the anchor into the wall material is drilled directly through the hole in the wood. |
 | Once the hole is ready, the anchor is inserted into it. Next, the anchor must be driven in with a hammer to its entire length, until the washer under the nut stops in the wood. |
 | And the last step is to tighten all the anchors using the appropriate wrench, thereby tightly pressing the mauerlat beam to the end of the wall. |
Will such a connection be reliable? With concrete - definitely yes. Directly dealing with gas silicate is a difficult question, even with a long anchor length. In any case, it was not possible to find any research or results of studying experience on this issue on the Internet - neither positive nor negative.
Let us focus on one more point. Often the length of the timber is not enough to lay the mauerlat along the wall in one piece, and you have to resort to splicing. Experienced carpenters can make very interesting and reliable interlock connections, but for a non-professional it will be enough to make a “half-tree” connecting knot. Required condition: At this point it will then be necessary to provide a fastening - an anchor or a stud to tighten the connection.
Prices for corrugated sheets
corrugated sheet
A similar approach is used in the corners where the beams of adjacent walls join - a locking connection followed by tightening with the selected fasteners.
In addition, in order to connect all sides of the Mauerlat into the most rigid frame possible, reinforcement of the connection using 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 a wall, you should strive to ensure that they are approximately the same length. For example, on a wall length 8,5 meters it is better to use beams not 6 + 2,5 , and, for example, 4,2 + 4,3 m.
Technological innovations – chemical anchors
A dozen years ago, few people had heard about these innovative methods of fastening parts in various materials. Today, chemical anchors are widely available for sale, although it is not yet possible to call them generally available in price.
By the way, many home craftsmen carried out similar fastening technologies without special chemical anchors - we are talking about those cases when a mixture of epoxy and hardener was poured into the hole made, and then the part was inserted - after a day a reliable connection was obtained.
The advertising accompanying such chemical anchors attributes to them the highest strength qualities. True, you can already come across consumer complaints, although perhaps they are related to the fact that there are a lot of low-quality counterfeits of such chemicals on the market. And if we talk about reputable manufacturers of such materials, then you should focus on the brands “Sormat”, “Hilti”, “Nobex”, “Fischer”, “Tox”, “Tecseal”, “Tecfix”, “Technox”, “KEW” and some others.
Chemical anchors themselves may differ in the principle of their use.
- So, one variety has a capsule (ampoule) layout.
An ampoule is inserted into the hole drilled for the anchor, which contains a one- or two-component composition, which begins to quickly harden after mixing and contact with air.
After placing the ampoule, the anchor itself (pin) is inserted into the hole and driven to the required depth. When clogged, the anchor destroys the ampoule, sucking and filling the entire space of the canal. Including between the walls and threads of the stud. At normal temperature air, after 25–45 minutes the composition completely polymerizes, hardens, and ensures 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 dispensing gun. The pistol 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 pistols.
In addition, depending on the wall material, additional devices may be used. For example, let's look at how to install a chemical anchor designed specifically for porous concrete.
| Illustration | Brief description of the operation performed |
|---|---|
 | The illustration shows the possible components of a set of Fisher chemical anchors - these are the cartridges themselves with compositions of different hardening rates, and dispensing guns. The channel for any chemical anchor always needs to be thoroughly cleaned of dust - for this purpose there is a special pump for purging and pumping out, and brushes of different diameters. A drill with a special attachment 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 the stud anchors themselves of various lengths. |
 | In this case, we are interested in the topic of the article precisely gas silicate wall– porous concrete. |
 | Drilling of the channel for the anchor begins. For this purpose, a special drill with a round stop-limiter and a spherical nozzle is used. |
 | First they drill straight hole– all the way to the limiter. |
 | The limiter rests against the wall, and thanks to the spherical shape of the nozzle, the hole begins to take a conical shape - as shown in the illustration. |
 | When the channel is ready, the drill is placed straight and carefully, so as not to accidentally break the narrowed top of the cone, and removed from the hole. |
 | After that they take hand pump– it is necessary to thoroughly clean the channel from dust. Purge begins with the pump probe completely immersed in the hole. |
 | Then the pump probe is gradually removed from the channel without stopping the blowing. If necessary, use a round brush of the appropriate diameter. This blowing operation should be repeated at least four times - the presence of dust sharply reduces the reliability of the chemical anchor. Ideally, you should strive to keep the channel completely clean. |
 | After cleaning, a plastic sleeve is inserted into the hole. It will “ennoble” the edge of the hole and, most importantly, ensure that the inserted anchor (stud) is positioned perpendicular to the wall surface. |
 | Chemistry is getting ready for work. The cartridge is inserted into the gun and the mixer spout is screwed on. A small release of the composition is made onto any surface - you need to make sure that all components are completely mixed - this will show the even color of the resulting mixture. |
 | After this, the spout is inserted into the coupling that limits the hole, and the cavity begins to be filled with a composite composition. |
 | Typically the cavity is filled to approximately ¾ of its volume. |
 | Next, a stud anchor 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, finger force is sufficient at this stage. It is important to ensure that the stud is in a position perpendicular to the wall - the guide sleeve will help with this, but it still doesn’t hurt to check. The pin is screwed all the way to the wall. |
 | All you have to do is wait just 45 minutes - and at normal temperatures (about +20 °C) the anchor will be ready for load testing. |
What else do they say about the advantages of chemical anchors:
- The fastening is considered to be highly durable and durable - its service life is estimated at 50 years.
- The polymer composite used is completely inert to atmospheric, biological, and chemical influences.
- When installing such an anchor, there are no thrusting loads inside porous concrete, that is, the risk of cracks or chips 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 few of them, but judge for yourself:
- The cost of chemical dowels is high, and attaching the Mauerlat will cost a very impressive amount. Moreover, our task requires very deep channels with their complete filling with a 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 there is basically nowhere to get temperatures above 100 degrees, but nevertheless...
- No reliable data on the timing and results of using chemical anchors for fastening the Mauerlat to aerated concrete without an armored belt has been identified. That is, there are assumptions that it should turn out well, but there are no results of the tests yet. Maybe you want to be the first?
Video: demonstration of working with a Hilti chemical anchor
Fastening the Mauerlat to embedded studs
If, even before attaching the Mauerlat, studs stick out from the end of the wall at the required distance from each other, the installation process is simplified to the limit.
- The location marks of the studs are transferred to the beam - to do this, just lay the Mauerlat on top and tap a little - the studs will leave marks that will become centers for drilling holes.
- Next, a strip of waterproofing is “pricked” onto these studs.
- Then a beam with drilled holes is strung.
- Wide washers are put on the studs, nuts are attached - and a completely understandable procedure occurs for pressing the Mauerlat to the end of the wall.
Everything is very simple, except for one thing - how to embed studs into an aerated concrete wall. This is where the difficulties begin.
There are such tips - in aerated concrete masonry a deep hole, about 500 mm, is drilled, with a diameter approximately 3-4 mm larger than the diameter of the stud. Then the channel is filled with masonry adhesive or cement laitance. After this, a pin is inserted into it all the way - and left in this form until the solution completely sets.
It would seem easy, but some craftsmen who have tried this method are clearly not happy with it - the solutions can shrink, it is difficult to avoid void areas, and the quality of such a unit is still not the highest. Some fasteners may 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 dire consequences.
Another option for installing studs in advance. In this case, they are welded perpendicular to metal plates, which will be placed in the masonry seam 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 provide 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 top row in advance, before they are installed in the masonry, then pins are inserted there, and if necessary, the edges of the block are “straightened” so that it does not become warped due to the thickness of the plate. After this, the masonry is done - and when the wall is ready, there is immediately a row of embedded studs for mounting the mauerlat.
The plates are hidden in the masonry seams, and the studs become a convenient aid for securely fixing 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 for refusing this simple, but very reliable, proven operation of pouring an armored belt that guarantees the strength of the roof structure being created? 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 performed |
|---|---|
 | If you look at all sorts of instructions and manuals devoted to the construction of houses from aerated concrete blocks, the issue of attaching the 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 not large area, if the climatic conditions of the region do not require pronounced snow and wind loads, etc. In a word, practically at your own peril and risk. Is it really so difficult to fill the armored belt in order to get away from this dependence at once - “if”? |
 | By the way, there is nothing particularly complicated in this, that is, nothing that even a novice builder could not do. Manufacturers of aerated concrete building materials have included in their assortment a special type of blocks designed specifically for the last row of masonry. They have a characteristic shape, which is why they are called U-blocks (for their resemblance to this letter of the Latin alphabet). In essence, this is a permanent formwork made of aerated concrete in the factory for pouring a reinforced belt. |
 | Look at the illustration - it shows different 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 face 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 for country house average size It will not be difficult to make it yourself right at the place of work. Moreover, you will still have to fill it manually, since the concrete pump will not be an assistant in this case - the “ribbon” is too narrow and shallow. 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 immediately start pouring it? However, many are stopped by the fact that U-blocks, which require less material during production, at the same time cost significantly more, since they are usually sold individually. But it turns out that such blocks can be made independently, using standard wall ones, or you can do without them altogether, using other technical solutions. |
 | So, U-blocks can be cut from standard wall blocks. |
 | To begin with, of course, markings are carried out - the width of the cut fragment... |
 | ... and its depths. |
 | The lines along which the cuts will be made are drawn. In this case, the master decided to cut out 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 craftsman probably has a tool for cutting them. Usually this is a powerful hand hacksaw with a large tooth. They begin to make cuts along the intended lines - to the depth of the “channel” being created. |
 | To achieve an even depth of the slot, the block is sawed alternately, achieving the required 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 craftsmen, such smooth and equal-in-depth cuts can be made with a circular saw. True, the release of the saw may be insufficient (you need at least 100 mm of cutting depth) - so finally you can work with a hand hacksaw. Why not an option? |
 | The block with the slots made is placed “on the butt”. |
 | Next, a hammer drill is used. A drill is inserted into its chuck - 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 hole being drilled 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 about 15 mm. |
 | Then the block is turned over and a similar operation is carried out on the opposite side. |
 | After this, a light blow with a hammer is usually enough - and the fragment, cut on three sides, falls out of the block. By the way, these fragments, if they have not broken, should not be thrown away - they may still be useful during construction. |
 | And to fill the reinforced belt, this homemade U-block remains. |
 | If necessary, the remaining irregularities can be trimmed with a chisel... |
 | ...sweep away the crumbs and dust... |
 | ...and send the finished block to the place of their storage before starting masonry. |
 | After a sufficient number of homemade U-blocks have been prepared, they proceed to laying the last row of the wall. Work usually starts from the corner. |
 | Adhesive for aerated concrete is prepared from a dry mixture. The blocks are laid out sequentially. Everything is the same as with normal masonry - first, glue is applied in a layer of the required thickness... |
 | ...then this layer is leveled and distributed using a notched trowel... |
 | ... and after that another gas silicate U-block is installed. The work continues in the same 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 places where walls join - 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 also quite acceptable. |
 | To some, this approach may seem overly labor-intensive, and, in addition, accompanied by big amount waste. Well, this is true to a certain extent, and it is quite possible to use other methods for creating formwork for an armored belt. Here's one of them. To create the walls of this peculiar permanent formwork in this case they are used gas silicate blocks smaller thickness - they are often called additional ones. For example, you can use blocks 100 mm thick to create an external wall. |
 | A number of these blocks are laid with glue along the outer contour of the wall (the illustration shows only an example of installation). |
 | Any armor belt, due to the specific thermal properties of concrete, always turns into a powerful “cold bridge”. To reduce this drawback, it is advisable to immediately provide a layer of insulation - lay extruded polystyrene foam with a thickness of about 50 mm along the outer wall of the permanent formwork (if the width of the wall block allows it). |
 | 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 glue. |
 | The result is something like this: a channel for further filling of the reinforced belt (shown in the illustration with the reinforcement cage already laid). By the way, you can slightly reduce the depth of the “channel” if it turns out to be too large. On the bottom, also on glue, you can lay fragments cut from additional blocks, so that the depth is around 150 ÷ 180 mm - this is quite enough. |
 | There are other options. For example, on the one hand there is the same 100 mm gas silicate block and a layer of insulation, and on the other there is simply wooden (or OSB) formwork, pressed to the surface or placed exactly at the end of the wall. |
 | But here is an option without using gas silicate blocks at all. Wooden formwork is installed on both sides. But on the outside, along the formwork boards, a strip of polystyrene foam 100 mm thick and a width corresponding to the height of the created “channel” for the armored belt is laid. |
 | This option is, so to speak, live - with insulation installed along the outer perimeter of the formwork. Although insulation is not mandatory in this case, it should not be neglected - this has already been discussed above. But it is not needed on the internal walls - if it is also planned to pour a reinforced belt there, then only wooden formwork on both sides will be sufficient. |
 | After the formwork (in any of its versions) has been placed, they proceed to knitting the reinforcing frame. As a rule, an armored belt under the Mauerlat does not require too much reinforcement - four periodic profile rods (class A-III) with a diameter of 10 mm are sufficient. |
 | The spatial position of reinforcement bars can be ensured in various ways. The “classics”, of course, are clamps made of smooth or corrugated reinforcement, with a cross-section of 6 or 8 mm. - approximately the same as on a strip foundation. |
 | But often this scheme is simplified - it still looks “heavy” for an armored belt on top of a wall. If you look at the examples presented, 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. |
 | Tying is done in the usual manner - using steel tying wire. |
 | And this is the picture we get after linking - a neat spatial structure of four longitudinal reinforcement rods. |
 | Here's another original solution. Apparently, the owner has the opportunity to obtain waste from the production of metal products inexpensively (or even for free). One can only envy such creativity! |
 | Be that as it may, no one can cancel the rules for tying reinforcement, especially in areas of reinforcement (longitudinal connections of rods, turns, junction areas). Therefore, appropriate bends, overlaps, clamps, etc. are made. - everything is according to the rules strip foundation. By the way, pay attention to an extremely important nuance. The presence of a reinforced belt leaves virtually no difficulties for the subsequent fastening of the Mauerlat - mature concrete will hold even ordinary expansion anchors perfectly. And yet, before pouring concrete, you can do one more operation - install the studs in advance, linking them to the reinforced frame. After the belt hardens, the craftsman will immediately have ready-made, reliable fastenings for the timber at his disposal. |
 | 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 pin itself is tied to the jumper of the frame reinforcing structure (as shown in the figure). |
 | The pin can also be located offset from the center line of the armored belt - it all depends on its width and the planned location of the Mauerlat. The figure shows how the embedded pin is tied to the longitudinal reinforcement rods. |
 | Here we show how, in order to save money, lengths of threaded rods are simply welded to the transverse reinforcement clamps. True, for this you already need to have very good electric welding skills. |
 | If you screw a nut into the bottom of the stud and put on a wide washer, the reliability of the resulting fastening will increase significantly. After the poured concrete belt has fully matured, it will be almost impossible to pull out such a pin. |
 | The step for installing the studs is usually taken the same as the step for the future installation of the rafter legs. In this case, it is desirable that these mounting points for the Mauerlat be located between the rafters - so that they do not interfere with further installation operations. |
 | After installing and tying the studs, it is recommended to cover the upper threaded part, together with the attached nut, with stretch film so that the threads do not become clogged 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 solution is being prepared. As a rule, for such an armored belt, the concrete grade M200 is sufficient (but not lower). In a medium-sized house, a large amount of concrete will not be needed for these purposes - you can easily make it yourself in a concrete mixer. |
 | Then ready solution is fed to the top (in buckets), and gradually the “channel” of the armored belt is filled with it. |
 | It is very important to ensure that there are no unfilled voids left when pouring. To do this, the poured concrete is carefully “bayoneted”, that is, pierced along the entire length of the poured area with a piece of reinforcement or a pointed wooden strip - this will allow air bubbles to escape. |
 | After “bayoneting,” the solution is compacted as much as possible using a trowel or spatula, while simultaneously leveling the surface of the belt being created. |
 | So they move on sequentially along the entire length of the belt being created. |
 | The belt is filled and leveled. This illustration shows an option without studs - the owner assumes the use of conventional expansion anchors for mounting the Mauerlat. |
 | But here is an option - with tied embedded pins. After pouring the belt and its final maturation, ready-made fastenings are available for the craftsmen who will work on the rafter system. In any case, the armored belt must be given time to mature properly - it is advisable to start further robots no earlier than a month after pouring. |
As promised above, here are some supporting materials:
Reinforcement of a strip foundation - how to do it right?
It has already been 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 corners. Details are given in a special publication on our portal. And in another article they are given. Plus, both articles contain 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 an armored belt, and the number of components for its manufacture.
Foam concrete blocks great choice for building a house. They combine the functions of structural material and thermal insulation.
However, due to the presence of pores, walls made of them differ from dense brick or concrete. Therefore, many people have a question - how to attach the roof to the foam block? In our article we will try to answer it by considering possible options execution of this unit of buildings.
Why you need to pay special attention to attaching the roof to a foam block structure
It's all about the porous structure of the material, it can be seen in the photo above. It can easily withstand loads distributed over a large area. If you apply it pointwise, the surface will be pressed through.
The thin walls between the pores are easy to destroy. This does not happen with brick or dense concrete. For the same reason, the fasteners become loose in the foam block. It is easy to drive a nail into it, but it will not sit firmly; you can loosen it and pull it out even with your bare hands.
Therefore, it is necessary to pay special attention to fastening the roof in foam block buildings. If the procedure is not performed correctly, the walls may collapse.
Types of roofing for foam block buildings
All types of foam block buildings are used existing types roofs. In principle, they can be divided into only two groups, flat and pitched.
Flat roofs
There are no problems with them at all. Covering or ceiling slabs are laid on the walls and a roofing pie is made over them. The load from the slabs is evenly distributed over the entire cross-sectional area of the walls.
The foam blocks on which the roof rests find themselves in the same conditions as if we continued to build the wall higher, and this would be the weight upper floors, not roofs.
Pitched roofs
There are more types:
- single-pitched;
- gable;
- attic;
- hip or hipped;
- half-hip.
In addition, there are roofs of complex shapes that are not classified. But that doesn’t matter to us, all these roofs mean truss structure which supports the roof.
The load from the rafters, if they are attached directly to the walls, will be point-like, which is why problems arise in designing the attachment points for the roof to the foam block. First, let's look at the features of rafter structures.
Elements and types of rafter structures
As is clear, the main detail is the rafters, connected to each other by lathing; they support the weight of the roofing pie.
They are divided into two types:
- layered;
- hanging.
The first rest at both ends (the lower ones are called rafter legs) on walls, mauerlats or racks.
The second type is supported only by the legs, the upper ends hang freely. Together with other elements they can form a roof truss.
The picture above shows the most common types of roof trusses (we don’t call them structures, as this means all the rafters and sheathing).
And two more explanations:
- The headstock in the fourth picture is the same as the stand; the author of the picture used a term more common among restorers than among engineers (the author of this article has almost never encountered it).
- The tightening is also more often called a screed (in general, many construction terms have many names; this is even found in regulatory documents).
Fastening without armored belt
Let's immediately look at a simpler way to install a roof on a foam block, when the roofing parts are laid directly on the masonry surface. This option is most often used in small buildings erected by hand.
What to pay attention to
When attaching a roof to a building made of foam blocks, you need to pay special attention to the following details of the truss structure.
Mauerlat
Parts of the rafter system cannot be attached to the foam block without this part. The Mauerlat will evenly distribute the weight of the roof over the entire wall area. Its width should be maximum; it is best if it is equal to the width of the wall.
The mauerlat is attached to the masonry using pins or dowels inserted into it. It is advisable to plant them on a solution or glue them. Also, the diameter must be chosen at least 30 mm; the larger it is, the less loosening of the fastening in the foam block will be.
Rack, upper ends of layered rafters
If the racks or upper ends of the layered rafters rest on a partition, also made of foam block, then a purlin must be placed on top of it. It will distribute the load over the entire area, just like the Mauerlat on the external walls.
Puffs
Hanging rafters “move apart” to the sides without tightening. Only a wall can prevent this. In the case of a foam block, this load can loosen the studs that secure the Mauerlat. Therefore, the tightening must be mandatory and preferably not raised.
For the same reason, it is undesirable to install an attic roof, the side rafters of which also transmit horizontal force to the wall. You can bypass all restrictions if you additionally secure rafter legs, extended beyond the dimensions of the wall to the floor beams, which will act as tie-downs.
Fastening the roof with an armored belt
More reliable design it turns out if you provide an armored belt (the second name is a monolithic belt).
What is an armored belt
The armored belt is a strip of monolithic reinforced concrete up to 0.5 m thick along the upper edge of the wall. It is installed not only on foam blocks, but also on masonry made of any piece material (for example, brick).
Its task is to additionally connect the masonry and evenly distribute the loads across all four (or more) walls. In the case of cellular concrete, it additionally protects the surface from crushing.
A monolithic belt can be made in formwork, but usually two rows of small-thick blocks are laid out on the outer and inner sides of the wall so that a tray is formed between them (sometimes a tray is cut out to form a “U” block). A reinforcement frame is installed in it and concrete is laid.
The installation of an armored belt slightly complicates the design of the building, but increases its reliability and strength. The cost of construction also increases slightly, since little steel and concrete are needed. For buildings with a large area and a heavy roof, a monolithic belt is almost mandatory.
Fastening the roof to foam shells with armored belts
The rafters can be attached to the armored belt without the Mauerlat using the same methods, but it is better to install it. It is easier to install fasteners into the Mauerlat tree. The Mauerlat itself is connected to monolithic belt two ways, the instructions are as follows.
- When pouring concrete, anchor pins are placed into it. They drill holes in the Mauerlat for them and tighten it to the concrete with nuts and washers. The most reliable method, but requires precise marking of holes before drilling. The video in this article shows exactly this option.
- The holes for the studs are drilled after the Mauerlat has already been laid on the concrete. The drill goes through wood and concrete. Additionally, the studs can be secured with glue or self-expanding anchors can be used.
Attention. Waterproofing must be done between the Mauerlat and the wall (armoured belt).
The first two methods of installing rafters are shown in the figure after the title of this section of the article; they are the most common.
- In the rafters, ledges are selected with which they rest against the mauerlat. Additionally, corners are installed along the edges. You can also choose grooves in the Mauerlat; this will secure the rafters more securely and eliminate the possibility of them moving along the wall if the corner collapses.
- The rafter structure rests against the Mauerlat with a low tightening - angles are also installed.
Note that you can additionally tie the mauerlat and rafters with wire. Other methods of installing rafters are shown in the figure below.
- Support bars are attached to the rafters using steel plates, with which they rest against the mauerlat. Additionally, a rolled metal square can be fixed along the mauerlat, under which a transverse groove in the rafter leg is selected.
- The thrust block is secured with a steel plate and two bars, which also create additional support.
- This method has already been shown in the previous figure.
- A “V”-shaped recess is selected at the end of the rafter, with which it rests on the mauerlat. In this case, the rafter leg does not extend further than the wall.
- A combination of methods “1” and “4”.
- Method “4”, but in this case the continuation of the rafters, forming an outlet beyond the walls, are bars, on which stops are also selected.
Advice. Foam concrete is easily saturated with moisture, including from rain. Therefore, be sure to make large roof overhangs, for which rafter extensions are necessary.
Note that on all proposed fastening points, in addition to option “4”, there is also an additional fastening - a clamp. It is made from wire, tape and other similar materials.
It wraps around the rafter leg and pulls it down. The clamp itself is attached to the inside of the wall using dowels. It can be used if you need to ensure additional reliability of the connection between the wall and the roof, for example, when the roof is very heavy.
That's all we wanted to tell you about how to put a roof on foam blocks. We hope our article was interesting and brought practical benefit to you. It’s great if you were able to use our advice and implement one of the design options for this unit during construction on your site. Let the roof of your house be reliable and the sky above it cloudless.
The question of how to secure a Mauerlat to aerated concrete without an armored belt is quite rare, because such a connection is rather nonsense in construction. To understand this, you need to understand why the armored belt is needed, and what the Mauerlat is and its purpose.
Is this aerated concrete?
But first of all, let us note that the construction of houses from aerated concrete is at the peak of popularity, and the demand for this building material is growing. This means that many people encounter it when building their own houses. What you need to know about aerated concrete:
- belongs to the category of porous materials;
- good thermal insulation qualities;
- not the lowest moisture absorption;
- good load-bearing capacity;
- low strength.
Exactly last characteristic determines the possibility or impossibility of laying the Mauerlat on aerated concrete. Because the porous structure of the material does not allow it to be heavily loaded, especially pointwise.
As for the Mauerlat itself, it is a structure that is laid on the upper surfaces of the walls. In fact, it performs the functions of a strip foundation, evenly distributing the loads from the roof onto the walls of the house. They are made mainly from wooden beams with a minimum cross-section of 100x100 mm. It should be added that this roofing element simplifies the fastening of the rafter system to the walls.
Armopoyas: design features
Now about the armored belt. Its main task is to fasten the Mauerlat. And if it is not included in the structure of the house being built, then certain problems arise specifically related to the fastening of the mauerlat beam. There are several mounting methods. They are perfectly used by builders if houses are built from more durable materials: brick, stone, concrete blocks.
Mounting methods
So, we are familiar with the main elements indicated by the question of how to attach the Mauerlat to aerated concrete. It remains to figure out the methods and understand one important idea. But the idea is that the proposed fastening options must be accepted with a large number of reservations. Because installing a Mauerlat on aerated concrete blocks without pouring a reinforcing belt is a rather dubious undertaking.
And no matter how much you look for technologies, they will all turn out to be at least of little use. And with each option there are a huge number of contraindications. And although some portals contain a lot of information that it is possible to lay the mauerlat on aerated concrete and secure it, everyone unanimously assures that there are certain criteria that must be taken into account.
Eg:
- you can use this method (without an armored belt) if the structure being constructed is small in size;
- if the roof is a simple structure covered with lightweight roofing materials;
- if the design of the rafter system uses hanging rafters, which are tied together with reliable ties;
- if layered rafter legs are installed, supported along the axis of laying the ridge beam.
By the way, the last option is best suited to this situation. Because part of the load from the roof will fall on the supports under the ridge, this will reduce the load on the walls. And yet, before attaching the Mauerlat to aerated concrete, you need to think carefully about whether it is worth carrying out this process without pouring an armored belt.
Option #1
Fastening the Mauerlat to aerated concrete without an armored belt is best done using steel wire with a diameter of 4–5 mm, which is twisted into 2–4 layers. This method is often used when laying mauerlat timber on brickwork. How this process is carried out. There are several strict requirements:
- the wire must be laid in the masonry of aerated concrete stones in the third or fourth row before the end of the masonry, that is, 3–4 rows of blocks must be laid above the wire;
- the length of the twist should be such that on both sides it reaches the laid mauerlat, overlaps it and twists, creating a fastening;
- The step of laying wire twists is equal to the step of installing rafter legs.
An example of fastening a mauerlat beam using wire Before laying the Mauerlat without an armored belt on walls made of aerated concrete, the ends of the walls must be waterproofed. The easiest way is to spread the roofing material in two layers. After which the timber itself is laid. It must be aligned either with the outer surface of the wall or with the inner one. Horizontal alignment is required. Then the wire braids are tightened using a pry bar. The main thing is that the screed is strong and tight.
Example of correctly tightened wire braids using a pry bar It seems that this is the solution to the problem. But let's think sensibly. Strong tightening of gas silicate blocks can lead to cracking of the material, this will be especially noticeable during the operation of the roof, when wind loads act on it. They will make the wire work like a saw. But it is with this tool that blocks are trimmed when it is necessary to adjust them to the required dimensions.
That is, this option, although seemingly correct in use, raises serious doubts. And the more you tighten the Mauerlat with wire, the faster it will cut the blocks.
Option No. 2
Installation of mauerlat timber without reinforced belt using anchors and dowels. For fastening, they suggest using anchors with a length of at least 30 cm, preferably 50. Appearance they have this: 
How this process is carried out:
- After waterproofing their upper ends, a mauerlat is laid on the walls.
- Every 1-1.2 m in it, as well as simultaneously in aerated concrete blocks, holes are made with a drill and a drill bit, the diameter of which is selected to match the diameter of the dowel for the anchor.
- The dowels get clogged.
- Anchor bolts are screwed into them.
To attach the Mauerlat to aerated concrete without an armored belt, it is better to use anchors with a diameter of at least 12 mm. And one more thing - select a washer of a larger diameter under the nut.
So, can this method really be considered reliable? If this concerned a reinforcing belt made of concrete mortar, then there was no doubt. This is a one hundred percent reliable mount. With aerated concrete, even if anchors are used long length, there is no certainty that this type of fastening will be able to withstand the serious loads emanating from the roof structure. It’s one thing to fix a shelf, cabinet or TV on aerated concrete, but it’s another thing when the load from the roof is more than one ton various materials.
Option #3
Attaching the Mauerlat to aerated concrete wall using pins. A pin with a diameter of at least 12 mm is used here. It is laid across the wall in a masonry of blocks below the last row by 2-3 blocks. It will turn out that the threaded ends of the studs will stick out from the wall on both sides. Therefore, its length is chosen according to the width of the aerated concrete wall.
In this case, the Mauerlat is laid on aerated concrete in exactly the same way as in previous cases. But the fastening is done wire twist. Loops are made at the ends of the steel “braid”, which are put on the ends of the hairpins. That is:
- first, one loop is put on, for example, on the outer end of the fastener;
- it is tightened with an M12 nut with a wide washer placed under it;
- twisted wire is thrown over the wall, and so is the Mauerlat;
- the free loop at the opposite end is inserted into the free end of the hairpin;
- tighten with a nut and washer;
- You will need a pry bar, which is used to tighten the twist on top of the mauerlat beam, that is, to pull the latter to the wall.
We must pay tribute to this method of attaching the Mauerlat to a wall built from aerated blocks. In many respects it is more reliable. Firstly, the wire does not come into contact with the aerated concrete material. This means that there is no load from twisting it that could cut it. Secondly, the stud is laid without violating the integrity of the blocks, which is very important for aerated concrete material. But even this option does not guarantee 100% reliability of the fastener.
Option No. 4
Today we need to talk about innovative fastening methods, because scientific and technological progress does not stand still and offers us new materials that increase the strength of fastening. These are so-called chemical anchors. Essentially, this is the same metal device that is inserted into the wall. But instead of a metal dowel, a two-component adhesive composition, which upon contact with air quickly polymerizes, forming a strong connection. A steel anchor is inserted into it while the material has not yet become hard. 
Today, manufacturers offer two types of chemical dowels:
- A ready-made two-component composition in a can, onto which a pistol nozzle is attached for ease of supplying the mixture.
- The composition is in a glass capsule, which must be inserted into the prepared hole. Then an anchor is inserted into it, which breaks the capsule, thus mixing the two components with each other and creating conditions for their contact with air.
The process of attaching the Mauerlat in this way exactly repeats the technology with conventional anchors and metal dowels, which was considered in option No. 2. Only instead of a steel dowel, either a capsule is inserted into the prepared hole, or a composition from a spray can is poured. The most important thing in the latter case is to insert the anchor immediately after filling the mounting hole with a two-component chemical composition.
It should be added that manufacturers of chemical anchors today offer varieties specifically for aerated concrete materials. These are the ones that should be used for fastening.
Now, as for the reliability of the fasteners. This is one of the most reliable options. But there is no information that anyone has already used it. Therefore, we can only speculate. Although theoretically everything should work.
Option #5
The same studs are used here, only they will be installed vertically and serve as anchors. Steel strips with a thickness of 5 mm, a width of 50 mm, and a length equal to the width of the wall are welded to them. The device is installed at the stage of wall construction 2–3 blocks below the upper plane of the end. Therefore, it is important to accurately determine the length of the hairpin. The installation orientation is a strip across the wall. This option is best used if the walls are raised from two blocks, so the studs will be between the blocks without violating their integrity.
A good mounting option, one of the best, but on one condition - the weight of the roof should not be large. In this case, the load on the walls is oblique, so the fasteners work in bending. The wider the fastening structure stripe, the better.
Generalization on the topic
Several options have been proposed for attaching the Mauerlat without filling the armored belt. It’s difficult to say how the entire structure will behave, whether it will be reliable fasteners. Therefore, you should not take risks and avoid expenses. Fill the armored belt and all your problems will be solved instantly.
How to attach the Mauerlat to aerated concrete without an armored belt?
On manufacturers' websites there are conflicting statements regarding the need for building a building from aerated concrete blocks. Some argue that they are quite capable of withstanding the expected load. Others, on the contrary, suggest playing it safe. However, all manufacturers and builders are confident that porous materials react negatively to point loads. Therefore, it is necessary to distribute it evenly. If for any reason the installation of an armored belt is not possible, it is necessary to use. This will extend the life of the structure.
The Mauerlat is most often made from the same material as the rafters - metal (channel, I-beam) or wood (timber)
What is a Mauerlat
This is a special design that is used to distribute the weight of the roof evenly across the walls. As a rule, it is made of wooden beams. It is to the Mauerlat that the rafters are attached to make the roof stable. The durability and reliability of the entire structure depends on the quality of installation.
The Mauerlat can be metal, but only if steel rafters are used. However, such structures are rare, since the cost of construction increases significantly. In addition, fastening steel parts is much more difficult than wooden ones.
Mauerlat functions:
- uniform distribution of the weight of the roof over the walls;
- reliable fixation of the rafter system;
- protection and prevention of point loads on aerated concrete blocks.
The minimum size of timber used as a mauerlat should be 10*10 cm. However, to ensure best quality For clutches, it is advisable to use a material with a larger cross-section. It is permissible to use a log, but it is necessary to cut off the side that will be adjacent to the aerated concrete.
The rafter legs at the points of support transfer the load to the mauerlat, which, transforming and distributing, transfers it to the walls
Hardwood timber performs these functions best. In order for it to last longer, it must be treated with antiseptics and impregnations that prevent rotting and insect damage. The beams must completely and evenly cover the walls. They are fastened together with nails or a straight lock. Due to the fact that the cross-section of the wooden material is smaller than the width of the gas block, the Mauerlat is placed on the inside of the walls. The distance to the outer edge must be at least 5 cm. Laying bricks on the outside of the building is also permissible.
There must be a waterproofing layer between the aerated concrete wall and the wooden Mauerlat.
Methods for attaching the Mauerlat
The Mauerlat can be attached directly to aerated concrete or using an armored belt. There are such connection methods wooden beam with wall:
- using steel wire;
- using anchors;
- stiletto heels.
When using any of the above methods, you must ensure that the fastening is of high quality and reliable. Also, during installation, structural shifts should be avoided.
In private housing construction, wooden beams are the main material used to work on the mauerlat
