In the forest areas of Russia, Scandinavia, Canada and North America, log houses have long been built. Logs or beams are sequentially stacked in rows, which are called crowns.
Mezhventsovy insulation is an important component of this construction technology.
What is it for
The preparation of a tree trunk for use as a wall material is now done by mechanical processing on special machines. Logs are cylinderized by turning and have a perfectly round section along the entire length. And profiled glued timber, which has special grooves for a tighter connection, is considered the best material for solid wood walls. But even in this case, there is the possibility of blowing the walls through the horizontal seams between the crowns.
Wood is a living material. It is the unique natural qualities of wood that make the atmosphere of a log house so valuable. But hence the main disadvantages of wood as a building material. It is subject to shrinkage and deformation under the influence of seasonal changes in temperature and humidity, fromthe difference between the internal microclimate of the building and atmospheric conditions, from multidirectional loads experienced by different parts and structures of the house.
To prevent possible heat loss and compensate for inevitable deformations, interventional insulation is needed.
Function defines qualities
Mezhventsovy insulation must have the necessary properties.
Sufficient density and elasticity are necessary to eliminate the formation of cracks during the operation of the house. It should not crumple from the vertical load and fill the resulting voids.
Low thermal conductivity is needed to protect against heat loss. The ability to absorb excess moisture from the air and release water when it is lacking is one of the virtues of wood. The interventional insulation must also have vapor permeability so as not to reduce the comfortable qualities of wood. Hence the increased requirements for environmental friendliness. The release of harmful substances or allergens by the heater will negate the beneficial effect on the human body of the natural environment of a wooden house. The creation of an environment for the development of harmful microorganisms is also excluded.
Durability and economy are closely related. The need for frequent replacement of insulation and repair of seams will lead to unnecessary costs during the operation of the house. For decades, only high quality material can not change the physical and mechanical properties and chemical composition. Biostability is important, that is, interventional insulation should not rot and become moldy, should not becomefood for birds, rodents, moths, etc.
In the beginning there was moss
Moss with long fibers (red moss, sphagnum, kukushkin flax) is a traditional material for warming log houses in Russia. Its excellent qualities - low thermal conductivity, the ability to absorb and release moisture depending on the humidity of the surrounding air, bactericidal properties - are difficult to reproduce in artificial materials. The main drawback is the difficulty in organizing industrial harvesting and laying.
Material based on plant fibers is the best interventional insulation. Especially when it is specially prepared for laying on logs or timber. Flax fiber, hemp (hemp fiber) have long been used in the form of tow for insulation and caulking of seams. Modern manufacturers pass them through carding and needle punching machines and offer easy-to-use rolled strips of flax felt and ribbon tow.
In a similar form, jute interventional insulation is supplied to the construction market. It is based on raw materials of plant origin, supplied to Russia from the countries of Southeast Asia and Africa.
Not all fibers of natural origin can be used as interventional insulation for timber or logs. Cotton or wool batting, felt is absolutely not suitable for this purpose. In addition to low density, they strongly absorb water, and moths inevitably start in the wool.
Mineral and synthetic
BIn modern construction, for the insulation of walls, ceilings, ceilings, roofs, many materials are used in the form of mats, blocks, rolls, aerosols, etc. They have excellent performance in terms of heat protection and moisture resistance, but are completely unsuitable for use in wooden housing construction.
The main reason is the complete non-compliance with the requirements for vapor permeability. Heaters based on glass wool and bas alt mineral raw materials are compressed under the weight of the crowns. The air from the space between the fibers is squeezed out and an impenetrable barrier is formed for the water vapor contained in the air and in the wood itself. In addition to worsening the microclimate of the dwelling, excess moisture condenses on the border of wood and insulation and gradually destroys the wall array. In winter, places where moisture accumulates freeze through and the process of destruction of structures accelerates.
There is also no ventilation in porous polymeric materials. Expanded polystyrene, foamed polyethylene, rigid polyurethane foam, foam rubber, mounting foams, sealants and their combinations cannot be used as interventional insulation. In addition to wasted money, you can get a house that is uninhabitable and losing strength.
Exotic guest
Besides flax and hemp, there is another plant fiber. Jute interventional insulation is gaining popularity. Jute is a plant fiber extracted from an annual shrub of the same name that grows in subtropical regions of Asia and Africa. It belongs to the spinning (bast) plants of the linden family. In terms of application, it is similar to flax and hemp (technical hemp), but hassome qualitative differences.
Both clothes and bed linen are made from flax, and technical canvas for containers and ropes are made from jute. Compared to other plant fibers, jute fibers are more coarse and brittle. Experts explain this by the increased content of lignin in jute. It is a natural high molecular weight polymer that causes lignification of plant cells. At the same time, pectin and wax are almost absent in jute, which give elasticity and flexibility.
The elementary fibers that make up the jute strand are much shorter in length than those of flax and hemp. Hence the increased hygroscopicity (the ability to absorb moisture), because. the capillaries formed in the fiber are shorter, making it easier for water to saturate them.
Advantages and disadvantages of jute insulation
Jute fiber insulation is produced in the form of tow or felt tape 5-15 mm thick. Tow is better suited for a wall made of logs or timber, prepared without the use of calibration on machines. Insulation strips are conveniently laid on rows of logs and profiled glued beams. It is convenient to fix the tape with a stapler, even edges do not require additional caulking of seams, it is convenient to make mounting holes for dowels, etc.
The physical and technical qualities of jute fiber determine the pros and cons that an interventional insulation made from it has. Jute gives it a density, uniform along the entire length, resistance to decay,durability. Increased hygroscopicity can become a lack of material: excess moisture, accumulated in the insulation, can lead to freezing of the wall. Insufficient plasticity can lead to the formation of voids in the seams between logs or timber.
Approximately 2% of the cost of building a house goes to interventional insulation. The price of a linear meter of a linen strip 20 cm wide with a thickness of 8-10 mm is an average of 6 rubles. A similar insulation made of 100% jute - 12 rubles. Jute is an imported product, its cost is higher than domestic linen raw materials.
Best choice
The practice of professionals in wooden housing construction shows that a strip of needle-punched felt made from a mixture of linen and jute fiber is the best interventional insulation. Jute adds elasticity and durability to linen insulation. The proportion of jute fibers can be 10 - 50%. It is important to remember that the use of recycled materials (recycled jute bags) significantly degrades the quality of the insulation.
