A house made of straw and clay than to plaster. How to plaster walls made of clay and straw using modern materials? Clay plaster - composition and properties
Straw and pressed straw blocks have three real "enemies" - this is increased humidity, fire and rodents. Let's call them "obvious" shortcomings.
Building a home using straw bales may seem like a crazy idea at first glance. And by the way, for some, this alone is a serious limitation - the risk of being branded as a "black sheep" is not too tough for many. But still, this is not the only and not the main drawback and risk in the construction of a straw house.
Straw and pressed straw blocks have three real "enemies" - this is increased humidity, fire and rodents. Let's call them "obvious" shortcomings.
Disadvantages are obvious
1. Risk of rotting in high humidity
Straw with a moisture content of more than 20% begins to mold, rot and collapse the stems, so it is important to keep the straw blocks dry before construction begins, lay them dry and quickly close up with plaster.
During construction. The thatched walls are only partially ready, so they are covered with plastic wrap from the rain
This also leads to the conclusion that the thatched walls cannot be left open. At the same time, the choice of coatings is also limited: cement-sand plaster clay-sand plaster gypsum plaster gypsum sheets wood panels
There is a risk of mold growth for both unplastered and poorly made walls.
In areas with a constant humid climate, you will need high-quality vapor barrier on the inner surfaces of the outer walls. Wide roof overhangs protect the house from heavy rain.
2. Fire
The plastered pressed straw blocks have a high fire resistance, they are officially assigned a very high degree of fire resistance. A properly protected thatched wall is superior in fire safety to a wooden one. But straw scattered around the construction site can easily cause a fire. You need to be especially careful with straw in attics, attics, near fireplaces.
In confirmation - the story of a woman whose house burned down during the construction phase.
“A house was being built for permanent residence (autumn 2005). The plot was bought with a finished basement. The frame was attached to the foundation with anchors 14x220. The blocks were tied with two simple strings, they were not compressed in good conscience, because during laying, a lot was gutted ... The outer wall was covered with DSP, and the inner ones were sewn up with a board with a gap. House made of straw burned down Fire in a house made of straw during the construction phase Fire in a straw house during the construction phase.
In the photo you can see to what stage the house was built until it burned down (on the second floor, they managed to make a draft floor and interior partitions). At this stage, the builders began to lay glass insulation on the foundation on the 1st floor, heating it with a blowtorch (April 2006). According to them, windows were open on the second floor. After a while, it began to smoke under the skin and floor. They began to blow up, flood, but could not, the fire spread very quickly and burned the whole house. There are many versions, but I think there was a draft of hot air and, most importantly, a violation of fire safety…”
Prevention measures:
- no smoking on the construction site
- quickly clean up scattered straw
- always have a fire extinguisher handy
- do not use open flames until the walls are plastered
- use tightly packed straw blocks
- after laying the blocks, plaster them outside, and then inside the house, before proceeding with the interior decoration.
3. Rodents
“So the mice will eat it” is a very common statement about thatched houses. Why is it so widespread? Because mice can really settle in the straw in search of food and warmth. True, not in any straw, and not quite in straw :) It is inconvenient for mice to settle directly in straw blocks - they are prickly, but in the voids between the block and, for example, a drywall slab, they may well.
By the way, rodents are not the only small pests that can help you tear your house apart :) There are also birds and insects that can also choose straw as their habitat.
Preventive measures: use rye or rice straw for insulation (the mice do not eat it and do not settle in it), isolate all possible ways of access to the straw.
Disadvantages little mentioned, but real
4. Limitations in design
When using a load-bearing frame, design restrictions are small, but they exist, and they primarily concern the number, location, width and height of openings.
5. Thick walls
The width of the straw block makes the walls quite thick. One of the difficulties with walls of this thickness is the need to expand the foundation and increase the roof area. In homes with thinner walls, creating exactly the same usable interior space requires fewer resources.
Straw walls. Thick thatched walls protect well from frost, but increase the foundation and roof ...
6. Few standard projects
Unlike houses built using other technologies, there is a clear lack of typical straw block construction schemes. This means that the development of a straw house construction project will most likely have to be ordered individually, and understanding architects-designers-builders will have to be looked for.
In some countries, there are still no building codes (in Belarus it is regulated by SNIP, in the Russian Federation and Ukraine there also seems to be).
7. Timing and money
You need to immediately have a certain amount on hand in order to quickly solve the “must-have problems”. I will give one dialogue from the forum, which illustrates this point well.
- ... one BUT: if I put up a log house and I run out of money, I can live in it unfinished, but a thatched house requires both external and internal decoration, and right away.
- The cost of a minimum finish for living in a house is so insignificant that it does not deserve a separate discussion. If there was money for the frame, roof and windows, then there would be crumbs for plastering.
- Something tells me that it will cost at least $5 per square - and there are a lot of squares in the house!
- Necessarily! At least 5! If you don’t apply the handle yourself, but walk and poke your finger, it’s uneven here, grease it there ...
8. Timing and money - 2
We have suitable straw closer to August, and if there is not enough money, then you may not have time to do everything before winter. And in winter, external walls cannot be plastered. Therefore, there is a prospect of wintering straw under the roof of an unfinished house or outbuildings on the site, and after it, risk No. 1.
9. Pointing finger
Due to the fact that the technology of building from straw blocks is not yet very widespread, it will be necessary to monitor the progress of work much more and more carefully compared to building from "traditional" materials: so that the builders do not smoke, do not work with the burner, and that fertilizers are nearby did not turn out to be with straw (for example, ammonium nitrate - spontaneous combustion is possible upon contact with sawdust or straw), and so that children with matches do not appear nearby ...
P.S. Disadvantages of thatched houses with a load-bearing frame
You may have already heard that a straw house can be built frame and frameless. To be honest, I still have little idea of the process with such a frameless house, however, people call the disadvantages of straw construction with a supporting frame, so we’ll just note them “for show”. So, this is an additional expenditure of time, money, labor, materials to create a supporting system, when the blocks themselves could support the weight of the roof, as well as the need to create a foundation that carries the weight of the blocks and concentrated loads from vertical racks. published
The foundation for a thatched house, although lightweight, will still have to be arranged. The type of foundation can be different, it is selected based on the properties of the soil on the site. To simplify the task of thermal insulation of the foundation, polystyrene foam 100 mm thick is laid along the outer side of the foundation, and the thermal insulation sheets are buried in the ground deeper than the soil freezing level. For a thatched house, it is important that the level of the "clean floor" in the house is below the base of the first row of thatched wall blocks. This will help in case of water leaks to prevent the walls from getting wet. You can learn more about choosing the type of foundation for a house from our article.
house frame
The design of the house can be both frame and frameless. In the case of a house without a frame, it is necessary to follow some rules: the blocks must have a density above 200 kg / m 3, you cannot build a house above one floor, the length of the walls should not be more than meters. In addition, the roof structure can only be lightweight. That is, frameless technology is possible, but imposes a number of significant limitations.
Another thing is a frame made of wood or metal. With such a frame, you can safely build a spacious two-story house, while the frame construction technology does not differ much from the frames of panel houses.
Most of all, for the construction of a straw house, a two-row frame is suitable. With this design, the blocks are stacked between two pillars that perform load-bearing functions.
When building straw walls, it is imperative to bandage the blocks; they are usually coupled with wooden poles or reinforcement (40-60 mm in diameter). The rods are driven in vertically, punching blocks lying on top of each other. Straw blocks must be laid in a checkerboard pattern so that there are no overlapping seams. The bales are stapled after the fourth row.
In addition, the reinforcement must be concreted into the foundation in increments of a meter; the first two rows of blocks are placed on the reinforcing bars. Adjacent walls should also be linked together, and this is done using U-shaped brackets 30 mm in diameter, two per row.
Collect walls from straw blocks starting from the corners or from openings to the center. To further protect the walls from mice and rats, a fine-mesh net is laid under the first row of bales. And when the walls are erected to a predetermined height, the structure is strengthened by constriction with plastic tapes, one end of which is attached to the pin previously left in the foundation, then the tape is pulled around a wooden Mauerlat laid along the perimeter of the wall. You can read about other types of walls in the article "What are the walls of the house."
Openings for doors and windows are made as follows: the upper and lower boards of the box are brought out to about half the length of the blocks. Boards are attached after the walls are erected. A roofing material is laid under the boards, a reinforced mesh is laid on top, with a release along the edges of the opening up to 30 cm. The mesh is attached to the walls with a stapler or galvanized nails.
Plastering straw walls
After the walls are erected, you can start plastering, but before that you need to bring communications into the house, and only wires in a special cable channel. It is not worth laying pipes in straw walls - the process of condensation and, as a result, decay, is inevitable in this case. If the cables are wound up, then proceed to the plastering of the walls.
Straw walls are plastered in two layers, and if the block density is more than 200 kg / m 3, then work can be started immediately after construction, if less, it is necessary to give the straw time to settle and compact.
For plastering, cement-lime and clay-lime mortars are used. You will have to forget about cement plaster, because it does not allow the walls to "breathe", which is unacceptable for straw structures.
Cement-lime mortar is prepared as follows: one part of cement, 3-4 parts of fine-grained sand and milk of lime, which is added to the mixture until a solution of the desired consistency is obtained.
Clay-lime mortar is obtained by mixing one part of clay dough, 0.4 parts of lime dough and 3-4 parts of sand.
Before plastering, the walls are reinforced, both outside and inside, for this a steel or plastic mesh is used. The first layer of plaster is thick, 3-4 cm, it is a leveling layer. The second thin, 2-3 mm. After plastering, the walls are allowed to dry, after which you can start painting. The paint must be water-dispersed, oil paints in this case cannot be used for the same reason - they do not allow the walls to "breathe".
I have been planning to post this article for a long time, but I put it off, because this year I didn’t manage to finish what I started - my walls were plastered only once on the outside and then incompletely ... Next - 15 steps in the process of plastering a thatched house ...
1. Before plastering, the walls should be trimmed- for example, a large wooden hammer; I also saw an example of how the “excess” was cut off with a grinder or a chainsaw. First we do it from the side of the street - inside we will always have time :).
2. Then you can again check gaps between blocks and in openings - and fill them with straw or a mixture of chopped straw and clay.
3. Next, we wrap the frame with a mesh so that the plaster adheres more tightly.
You can use metal or plastic. There is one problem with the first one - mobile communications begin to be jammed inside the house. Therefore, I had in my plans a lower part of 1 meter - metal, everything above - plastic. However, in practice it turned out that the outside was covered with a plastic mesh 2 meters high.
You can plaster the walls both on top of the plaster mesh and without it, rubbing the plaster into the straw - the second option is laborious, but cheaper (you don’t need to buy a mesh - although the plaster consumption is 15-20 percent higher, so it’s worth calculating, perhaps) .
In addition, sometimes instead of a grid, a thin crate of slats or shingles is made.
4. For attaching mesh we use a metal wire or a nylon cord - we sew the blocks together with the mesh. It is optional, in principle. I started to do it, but then I realized that she would be fine anyway.
5. We close the openings with a film. I think it's clear why.
6. We install scaffolding. Also an optional item - it depends on the height of your walls, of course. One of the most .
7. Check the clay for plasticity- if you plaster with clay, of course.
I originally intended to do this, but eventually settled on lime plaster for the exterior walls.
8. We prepare the plaster mixture.
9. Check the mixture for readiness:) This is also not difficult - you can plaster a piece of the wall and wait for it to dry. If cracks appear, you need to reduce the amount of clay.
10. Plastering 1 time - rough.
Everyone from the films knows how mud huts were made in Ukraine — in large pits, a bunch of people stir the clay with their feet, and then women and children throw lumps of this mixture with their hands against the walls with all their might. In general, there is where to have fun :) But you can also use special devices for applying plaster - it will not be so romantic, but faster.
In the case of lime plaster, such fun, alas, is canceled ...
11. Leveling the thrown plaster grater board. There is an article about tools in more detail.
12. We are waiting for drying within about 7-10 days.
13. We plaster 2 times.
14. Plastering 3 times - finishing.
Linseed oil (about 5% by weight of the plaster) can be added to the top layer of plaster - it will become a good breathable and at the same time moisture-proof impregnation. Also, dye can be added to the third layer of plaster.
15. Optionally, paint the walls such as acrylic paint.
Some use potassium silicate (liquid glass) for finishing painting, which also forms a waterproof film. By adding pigment to it, you will get the desired color.
These are the steps I got - everything seems to be simple and it is quite possible to do it yourself. Write in the comments - let's discuss!
The wall of a thatched house after the first layer of lime plaster Typhoon-Master No. 28
In fact, straw has excellent adhesion, and therefore it can be plastered with anything - everything will equally apply and hold well.
However, today we will analyze two main types of plaster: cement and clay.
Some people mistakenly believe that clay is not strong enough for a thatched house and, in order to strengthen its strength, decide to plaster the house with cement plaster.
And everything seems to be fine, the house is perfectly protected from external influences, but what is the danger?
The bottom line is that clay plaster reliably protects straw walls and does not allow moisture to pass there.
Cement plaster, quite easily passes moisture both into the straw walls and back, forming condensate.
In order to give a more detailed answer to this question, let's turn to the chemical properties of these plasters. There is such a thing as hydrophilicity. In general, it shows how much the material loves and attracts water.
So, clay is more hydrophilic than straw, and therefore, all the water that is in the straw, the clay draws into itself, and then it evaporates.
At the same time, cement is less hydrophilic than straw, and therefore, all the moisture that is in the walls, the straw begins to absorb into itself. What does it threaten? After the straw has absorbed all the moisture, it will begin to become covered with mold, fungus, and in the end, it may simply begin to rot.
Now the second question: where can moisture come from in the walls if the wall is reliably plastered?
Moisture tends to move from hot air to cold air. In addition, it moves from high pressure to lower pressure. As a rule, the pressure inside the house is always much higher than outside, so all the moisture that is in the house (from the shower, kitchen, plants, sweat, etc.) gets inside the walls.
Further, if the wall is plastered with clay, then it delays the movement of water in the wall and at each stage the moisture gets less and less to the straw. But even the moisture that gets there is pulled back into the wall by the clay, due to its hydrophilicity.
If the wall is plastered with cement, it does not have such waterproof properties and passes much more moisture to the straw walls themselves, which is successfully absorbed by the straw in the future.
Therefore, one conclusion can be drawn: based on their chemical characteristics of these materials, it is not advisable to plaster the straw with cement, because in the future this can lead to its decay.
At the same time, clay plaster is much healthier, cheaper and easier to work with, and will also protect your thatched walls from damaging moisture.
In this article: the history of straw house building; thatched houses, over 80 years old; straw block - characteristics; selection of straw and straw blocks for building a house; how to build a house from straw - stages of work; straw house and necessary tools; plaster for straw walls; build a house out of straw - take fire prevention measures.
- DIY straw house
- At the end
Straw as a building material - history
Straw has been used as a building material since ancient times - the population of Africa has been building houses from it for thousands of years, thatched roofs and thatched attic insulation were very popular in Europe, Russia and Ukraine back in the 19th century. More than 150 years ago, a new technology for the construction of thatched houses appeared - a wooden frame, a wooden roof and walls filled with blocks of compressed straw. Actively developing the territory of North America, European settlers faced a shortage of timber in the flat territories of Nebraska and faced the need to live in dugouts covered with turf. The settlers who founded the town of Sandhills were especially unlucky - the local soils turned out to be so poor that it was impossible to remove sod from them without serious consequences for cattle breeding. Local farmers found another way out and began to build frameless houses from straw pressed into bales, coating the created walls with a clay-lime mortar with floor (chaff) mixed in it. The increased demand for straw bales led to the invention of mechanical stationary balers in 1850 and movable straw balers moved across the field by horses in 1872, and steam-powered balers a few years later.
In 1925, panels were invented in France, formed by straw stalks laid parallel to each other, tied with wire and covered with cement-clay plaster on top. This wall material never gained popularity in Europe, however, in the period from 1936 to 1949, several houses from straw-cement panels were nevertheless built, but only in Australia - local industrialists tried to save on building materials due to the remoteness of the continent from the rest of the civilized world, and the country practically did not possess its own resources. A noteworthy fact is that several Australian houses built from stucco thatched panels in the middle of the last century have been perfectly preserved to this day. By the way, in the late 90s, during the demolition of one such house in the town of Altona, the workers suddenly had difficulties - they were unable to manually dismantle the walls, they had to call in special equipment. In the 1980s, straw building became popular again, mainly due to the unique combination of heat-retaining, strength and environmental characteristics of straw blocks. In 30 years, more than 110,000 straw houses have been built in Europe, the USA, Australia and China. Since the mid-90s, several thatched houses have been built in Russia, Ukraine and Belarus. Characteristics of straw blocks
By and large, straw is a by-product of low-value agriculture - it can be fed to livestock only after heat treatment and the introduction of additives that increase nutritional characteristics, roofs have not been covered with it for a long time, and it is suitable only for soil mulching. Considering that cereal crops are grown almost everywhere in Russia, there is no shortage of this building material - building walls for a house with an area of 70 m2 will require straw remaining after a cereal crop from 2–4 hectares. Meanwhile, most of the straw left after harvest is usually burned. What is a straw block? It is a densely compressed bale, rectangular in shape, and consisting of dried stalks of cereals, from which the grain has been completely extracted. The overall dimensions of straw blocks can be different, the following are most suitable for construction: width 500 mm; height 400 mm; length 500–1200 mm. The weight of a half-meter-long block with a density of 120 kg/m3 is about 22–23 kg.
Flammability of straw. Indeed, the dry stems of any plant burn perfectly, however, in a compressed state, it is quite difficult to set them on fire due to the low air content inside such a block. For example, single sheets of paper also burn well, but if you try to set fire to a folded pack of such sheets, you can only char them around the edges - the same thing happens with a compressed straw block, despite the high flammability category G4. Since the wall, assembled from straw bales, is completely covered with clay or clay-cement plaster with a thickness of at least 30 mm, the risk of its ignition is much lower than that of the walls of a wooden frame. Low price and availability of material. Blocks can be formed from straw of wheat, rye, flax, rice, and also from hay. The cost of a straw block is ten times lower than that of a brick. Low thermal conductivity - 0.050–0.065. Straw conducts heat worse than wood (0.09–0.18) and brick (0.56–0.70). The thermal conductivity of compressed straw is reduced even more if the blocks are formed only from stalks oriented longitudinally with respect to the future wall. The energy consumption of a straw house is about 40 kWh/m2 per year, not particularly growing even in the conditions of low temperatures in the Russian climate. Reducing construction time and scope of work. The assembly of walls from straw blocks is carried out quickly, without any masonry mortar, does not require the involvement of specialists and construction equipment. Under a thatched house, a lightweight foundation, usually a columnar one, is sufficient. 
Finally, it is impossible to dispute the environmental performance of straw, a natural material that is not treated with chemicals during the construction process, since this is not particularly necessary. The disadvantages of straw walls are that insects and mice can start in them, with an increase in straw moisture content of more than 18–20%, putrefactive processes begin in it, destroying straw blocks. Both problems can be solved at the same time by pressing the blocks to a density of 250–300 kg / m3 - given the thick layer of plaster, it is extremely difficult for rodents and insects to penetrate such a dense wall, and with an increase in density, a straw block will absorb moisture worse. It should be noted that an increase in the density of blocks will lead to an increase in their weight by two to three times, which will create some difficulties when building a wall. To combat insects, it is necessary to sprinkle them with slaked lime when laying the blocks and use lime in the preparation of the plaster mixture. DIY straw house
The walls of the house are made of straw bales, formed by a baler and tied with polypropylene cord - you need to choose them carefully. Natural fiber or steel wire tying, sometimes used to create bales in agriculture, is not suitable for construction purposes - the wire rusts, and natural fibers are fragile and prone to decay. In some agricultural enterprises, straw is collected by round balers, straw rolls, in principle, can be rolled out and squeezed by a baler, but it is better not to do this - the straw will be severely crushed, which will affect its thermophysical characteristics.
What is the best straw? Rye or rice straw, and winter rye straw is most suitable, because. its stem is denser, taller and, in addition, winter rye is harvested earlier than other crops. To build a house, only dry, seedless and uncut straw is required - it is not necessary to form bales from wet straw, it must first be dried. How to evaluate the characteristics of a straw block? A dry bale with a length of no more than a meter and a density of no more than 120 kg / m3 can be lifted by hand - it is not particularly heavy. To check the humidity inside it, you need to put your fingers inside, then take them out and bring them to your nose - when immersed in the straw of the fingers, moisture should not be felt, when they are brought to the face, there should be no smell of rot. Remove a few straw stalks from the bale and bend them - brittle stalks mean old and stale straw, not good for building. Qualitatively compressed bales practically do not deform if they are lifted by the strapping, it is difficult to put two fingers under the strapping cord, the blocks have similar dimensions. Like any other building, a straw house needs a foundation, albeit lightweight, but still. Its type is determined depending on the characteristics of the soil at the construction site. To ensure the thermal insulation of the foundation and reduce the energy loss of the building in the future, you will need sheets of expanded polystyrene with a thickness of 100 mm or more - they are laid on the outside of the foundation and buried in the ground below the depth of its freezing. 
It is important that the level of the floor in the house is lower than the position of the first row of straw bales - in the event of water leaks, the straw-filled walls are guaranteed not to get wet. Next, we determine the type of construction of the house - you can build a building using a frame and without it. In a frameless house, walls made of straw blocks perform a supporting function, so it is more convenient to use bales with a density of at least 200 kg / m3. In addition, a frameless thatched house can only be one-story, with a wall length of no more than 8 meters, and the area of openings for windows and doors must be less than 50% of the area of the wall in which they are made. A house with thatched load-bearing walls needs a lightweight roof structure - a four-pitched roof structure will be optimal, the rafters of which are placed on a wooden mauerlat of two boards laid on top of the wall and interconnected by crossbars in increments of one meter. A roofing material is laid on the pre-plastered end of the wall before installing the Mauerlat. The overhang of the roofing cornice behind the wall is more than 600 mm. The advantage of a frameless straw house is its low cost and ease of construction. 
A wooden or metal frame for a two-story or large straw house is created similarly to the frame of panel houses. You can build a two-row frame and stack hay bales between two supporting posts. It is easier to fill the wall sections between the frame posts with straw blocks than to display frameless walls - we will focus on them, especially since the sequence of operations is largely the same. 
During the construction of a frameless or frame house, the ligation between the blocks is carried out with wooden stakes or metal rods (diameter 40–60 mm), driven vertically into straw bales located one under the other, laid in a checkerboard pattern (without matching seams), the higher the wall rows are raised , the more long stakes are needed. The bales are fastened together after the fourth row has been laid. Also, metal bars are embedded in the basement of the building with a step of 1000 mm - their length should be sufficient to pierce the blocks of the first and second row. In frame construction, straw bales are tied with bearing poles using horizontal metal pins, and the pins that fix the blocks in place can be walled up in the foundation and brought out under the Mauerlat, stringing compressed straw on them and clamping the Mauerlat beam with a threaded connection. Neighboring walls during frameless construction are connected row by row with two pins 30 mm in diameter, curved in a U-shape. It is necessary to carry out such fastening both along the external and internal line of the interface of the walls - at least two curved pins in each row. 
Before starting work on the construction of straw walls, you will need to make two simple devices: a press for crimping and bandaging the blocks before cutting; several pointed metal hooks for transporting straw bales. The press consists of a pole dug into the ground and securely fixed about a meter high, on which a wooden bar-lever is movably fixed. At the end of the lever, small grooves are cut, a nylon rope is fixed in them in the form of a loop. The block of straw to be trimmed is placed under this makeshift press, clamped with a looped leg, and tied with a plastic cord in a new location. The assembly of walls with hay blocks is carried out from the location of the openings and from the corners to the center of the wall. A fine-meshed polymer mesh should be laid under the bales of the first row as an additional protection against penetration of rodents into the walls; kraft paper or cardboard is laid between blocks with a density of less than 200 kg / m3 during the formation of each tier - it will prevent convective heat transfer inside the wall. In the process of laying rows in a frameless house, it is not necessary to drive the blocks into place with considerable effort - the wooden limiters-guides, previously set along the edges of the walls, may shift. Align the blocks in rows according to the level of twine stretched between the guides, using a board of sufficient size and a heavy hammer. The walls brought out under the roof structure should not only be fixed with hammered pins, but also pulled off with plastic tapes in increments of one meter - wrapping at the bottom of the metal pin protruding from the foundation, tying and pulling around the wooden Mauerlat at the end of the wall. Metal tape for tying walls is not suitable, because. cuts hands and is quite stiff - it is difficult to pull. 
In the openings under the doors and windows, vertical and horizontal boards are placed, forming a box, fixed with temporary wooden crossbars nailed to the boards. The lower and upper boards of the box are displayed beyond its borders - up to half of the neighboring straw blocks. Upon erection of the wall, the boards of window and door openings are fixed with pins in bales - the pins are driven into the vertical boards inside the opening, the horizontal ones, located above and below the opening, are fastened outside it. Before fixing the opening box, it is necessary to overlap roofing felt or roofing felt under the boards, lay a plastic or metal reinforcement mesh on top of it with an extension of 300 mm beyond the edges of the opening and fix it with 35 mm galvanized nails or 35 mm building brackets using a stapler. Reinforcement will strengthen the straw blocks and prevent the formation of gaps between the wall and the opening box. If the blocks have a density below 200 kg / m3, then nails and staples will not hold in them - in this case, the reinforcing mesh is fastened with a nylon thread or steel knitting wire pierced through the straw through and through. To sew a straw block with a thread, you need a homemade needle - a 10 mm metal rod, flattened and sharpened on one side, bent into an L-shaped handle on the other. A hole is drilled in the flattened end - a thread or wire is threaded into it, like a conventional sewing needle. 
After assembling the walls, you need to trim them in those areas where the blocks protrude especially - for this operation and for cutting the blocks during laying, you will need a chainsaw. Before the next stage - applying plaster - wired communications are brought into the wall in a cable channel made of self-extinguishing polyvinyl chloride. Pipes for water supply, heating and sewerage are not placed in a straw wall, because. cause moisture condensation and rot. The final stage of work on the creation of straw walls is the application of two layers of plaster. Nuance - if blocks with a density of 200 kg / m3 and above were used, then plastering can be done immediately after the walls are erected. In the case of less dense blocks, it is necessary to wait two to three weeks for the straw to settle and self-compact. Cement plaster cannot be used, it will prevent the passage of vapor-saturated air through the wall, in other words, it will prevent the wall from “breathing”. Suitable plaster solutions on a clay-lime and cement-lime basis, having an average fat content. 
The proportions of the clay-lime mortar: clay dough (clay mixed in water) - 1 part; lime dough - 0.4 parts; fine-grained sand - 3-4 parts. Proportions of cement-lime mortar: cement - 1 part; fine-grained sand - 3-4 parts; milk of lime (lime dough mixed with water to the consistency of milk). The sifted cement and sand are mixed in dry form, then milk of lime is added to the container with the mixture until the mixture of the required consistency is obtained. To reinforce a straw wall from its outer and inner sides, you will need a metal or plastic mesh, with a cell of no more than 30 mm. The first layer of plaster should be thick - about 25-40 mm, the leveling second layer - 2-3 mm, it is done with a creamy plaster mortar. After the plaster has dried, the walls can be painted with water-dispersed paints - oil paints will not work, because. act as a barrier to the air exchange of the walls. Straw walls need to be plastered - trying to avoid this by covering the straw bales with drywall, plastic or brick will create optimal conditions for rodents and insects, because. between the straw wall and the cladding there will be enough space for their life. In addition, panel and brick cladding of non-plastered walls increases their combustibility due to the same gaps. And yet - you should not use a vapor barrier of thatched walls, this will lead to rotting of the straw. 
Important: in the process of construction work on the construction of a thatched house, it is imperative to observe the following fire safety rules! During the laying of the walls, until they are completely covered with plaster and the perimeter is completely cleaned of spilled straw, it is strictly forbidden to smoke, weld and other types of work with heating to high temperatures, using an open flame and accompanied by sparks at the construction site. Uncompressed straw ignites easily, and the slightest spark is enough for it to ignite - you can’t joke with it! During the construction of a thatched house, the construction site must be equipped with fire extinguishing equipment - barrels of water, charged and serviceable fire extinguishers, hooks. If a fire does occur, you need to quickly sweep the walls with hooks and fill the smoldering blocks with water - it is important to prevent the wooden frame from igniting (in the case of a straw frame house), because. new straw bales will cost significantly less than a new frame.