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Zavkafedroy production of building materials NEFU Alexei Mestnikov on how to build in the permafrost without thermal insulation - EastRussia | Interview






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"Russians still save on housing construction"

Alexey Mestnikov on how to build in the permafrost without thermal insulation

Buy a wooden house in 2018 year will be more profitable - signed a decree of the Russian government on subsidizing rates on loans for the purchase of wooden houses factory manufacturing. Alexei Mestnikov, Doctor of Technical Sciences, Professor, Head of the Department of Production of Building Materials, Products and Structures of the Engineering and Technical Institute of the NEFU, spoke about the situation with housing construction in the Far East, new materials and construction methods of EastRussia.

"Russians still save on housing construction"
- Wooden houses in the country will sell cheaper. How will this affect the construction market?

- I am sure, thanks to the adopted state program, the emphasis in individual low-rise construction will shift to the construction of wooden houses. For a long time, a new approach to wooden housing construction is needed, since construction norms in this sphere are outdated. In particular, the construction of wooden houses in the country stalled due to the fact that the tree is a combustible material, which means that the risk of fires is high: it was more difficult to insure such a house for a larger amount, banks did not give a mortgage on it, a subsidy too. With the advent of materials with special fire-fighting treatment and changing building norms, the situation with house-building changes.

Now all the attention in the market is turned to the factory manufacturing - it's a complete house kit or, more simply, a ready house. Housing from wood can be bought with the same benefits as when buying an apartment: here you and the mortgage with a low interest, and the house itself can be well insured.

- What are the key problems in the construction of private houses in Yakutia?

- In my opinion, the problem of ventilation and air conditioning is acute. We faced this in the construction of new houses of cellular concrete. Private owners used to build low-quality wooden houses, which are everywhere thoroughly ventilated - and so it turned out that the difficulties of conditioning they were unknown. At us at occurrence of tight energy-effective houses the problem has emerged at once: in buildings the condensate was formed, air became musty and damp. In this system there should be not only a ventilation purge, but also air intake, which we did not foresee.

At one time I was in Switzerland - they told me that they had no problems with construction and production of building materials. All construction science in them is aimed at improving ventilation and air conditioning, affecting virtually every building in the country. In Yakutia, this problem did not pass over even large buildings.

Of course, it's one thing - Switzerland with its mild climate, and quite another - the severe Yakutia, where in winter there is a huge temperature drop: houses 22-24 degrees Celsius, and on the street-50 and below. Due to this, condensation is formed. Imagine: the house needs fresh air, and you can take it only from the street, where-50. As a result, the walls are formed frost, coursed and so on. We need to find a way around this obstacle - this is the whole scientific direction, it must be studied.

- What mistakes do people face when they start building their own house?

- People do not want big investments in the construction of their homes at the initial stage, especially if it is something new, unconventional. So everywhere. Perhaps it's the Russian mentality. For example, to conduct normal ventilation, you need to invest at least 150-200 thousand rubles - very few people agree. It's time for Russians to understand that building a quality home is a business that requires large investments, it is better not to save on it. Saving in construction as a result will turn into a lot of waste - then patch, it's a remake.

For the same reason, people who build a house in Yakutia, save on the foundation. They put a simple, not suitable for our conditions. And the durability of the building depends on the foundation.

Everyone knows that because of permafrost, stone houses in the republic are piled on piles. If you pay attention to the big houses in Yakutsk, you can notice that nobody lives on the ground floors: there are either shops or work offices. It's all about the cold floors. What kind of thermal insulation do not do it - it will not help, because the temperature in the bottom is -50 degrees and lower.

We worked on a new type of foundation, which would be both quality in conditions of permafrost, and easy to install: so that a person could fill it himself without ordering a drilling rig. It's all in the ground.

In our opinion, the house should not stand high on chicken legs - it should be put on the ground. So, usually when installing the foundation, one of two methods is used: the first one is the preservation of permafrost during operation, the second one with the assumption of thawing depth. We combine both options. So, using the heat balance of the earth, the regime of "warm floor" is provided, because the soil has a certain heat capacity. The problem is that the heat also goes from the house, because of what happens a defrost, which over the years only increases. To prevent this, we use the method of fixing the defrost at a shallow depth, so that it remains at one level, with the help of thermally insulated, low-depth piles with a broadened support. The bearing part of the piles is in the frozen zone. As the experience of building experimental houses has shown, the maximum deforestation of the ground when installing such a foundation was only 2,5 meters, and this is in September. One person can manually drill a hole in this way in just 45 minutes, and using a motobus - 10-15 minutes.

- Tell us about the use of local raw materials, cellular materials, which you mentioned.

- Using cellular concrete, we build houses without thermal insulation, because the material itself is both heat-insulating and structural. That's why we take it as a basis - literally speaking, it's a single-layered wall. There is no carrier layer, a layer of thermal insulation and finishing, as in modern homes. In addition, studies have shown that this material is fireproof. Using in the production of cellular concrete, our small innovative enterprise SVFU "Stroykompozit" from 2010 year built two 9-storey buildings in Yakutsk for university staff, two dozen energy efficient individual houses in the capital of the republic and the city of Olekminsk.

The basis of any cellular material is sand. There are two ways of making it: since the material is porous, it is created by gassing or foaming. We use the second one, because it is simpler - foam concrete can be manufactured anywhere. You can produce both non-autoclaved cellular concrete on the basis of cement, and autoclave with the use of lime. On the quality of strength the first is worse - they need to increase the density. And if this is done, then the same structural material is obtained, which requires additional thermal insulation. In autoclave materials, the strength characteristics at low densities are quite high, for example, for the same construction of a two-story house without a frame.

Unfortunately, autoclave production is not always organized: there must necessarily be gas and electricity, since high pressure is used.

To solve the problem of construction on the ground, I am now trying to get the government of the republic and the regional administrations interested in organizing the production of granulated foam glass. If we compare it with other heat-insulating materials, the foam glass is almost out of competition due to a combination of high thermal insulation, absolute incombustibility and water resistance. The material itself is durable and environmentally friendly.

The fact is that on its basis it is possible to manufacture lightweight concrete blocks on site with the properties inherent in autoclaved cellular concrete - this would solve the production problem on the ground: the main thing is that at hand there were a porous aggregate made of granulated foam glass, cement and a mixing plant. If the project is approved, then we envisage the possibility of organizing the production of granulated foam glass from the zeolite-containing rock of the Hongyuruu field in Yakutia. The choice of zeolite is due to the availability and huge stock of natural raw materials, low energy intensity of its processing due to the "softness" of the original rock.