Wood is one of the most common building materials in the world. It is widely used both for the construction of buildings and for interior decoration, due to its strength, durability and excellent aesthetic characteristics. Because this natural material, it is susceptible to biodegradation under the influence of moisture and microorganisms, so it is important to prevent the putrefactive process. How and what is used to treat wood against rotting?
Causes of rotting
The main enemy of wood is fungus, which causes it to rot. “Contamination” can occur as a result of improper storage and transportation. Active reproduction of microorganisms provokes a whole set of accompanying factors:
- High air humidity – up to 90%.
- Stagnation of oxygen.
- Exposure to moisture.
- Temperature changes and freezing.
- Prolonged contact with the soil.
Prevention of wood rotting
To prevent the appearance of mold even before the start of construction, there are many preventive measures. Since the moisture content of a tree after a felling varies from season to season, it must be dried in natural conditions for at least 1 year.
There are a number of methods to prevent biodegradation processes and the negative effects of moisture:
- Waterproofing.
- Coloring with special compounds.
- Roof waterproofing.
- Heat and vapor insulation.
The foundation for a wooden structure should always be located above ground level, it is also necessary to equip a drainage system and blind areas. Garden near the house with tall trees – bad idea, as they will interfere with natural drying.
Also, to prevent putrefactive processes, it is necessary to inspect the house every year. If signs of fungus are detected, the material should be sampled to determine its moisture content and density.
Preventive measures are important, since wood affected by the fungus has many physical indicators reduced: it becomes up to 30 times less hard, 3 times less dense. All this leads to distortion window openings, movement of walls, up to loosening of the structure.
Once biodegradation has begun, it can be contained using special means- both store-bought and popular.
Antiseptics
If mold has already appeared, its growth can be prevented using antiseptic agents. They suppress reproduction wooden surfaces microorganisms that cause rotting.
Today, the store usually has something to choose from antiseptics When choosing a specific product, you should pay attention to such indicators as possible harm to humans and animals, anti-corrosion properties and impact on the quality of wood.
All antiseptics are conditionally divided into 3 groups:
- Water-soluble products.
- Oily.
- Pasty.
Water-soluble antiseptics
The most common impregnation is sodium fluoride. Its popularity is due to a set of significant advantages:
- high efficiency;
- good penetrating ability;
- no unpleasant odor.
Sodium fluoride does not impair the aesthetic properties of wood and does not cause corrosion of metal parts that come into contact with it. In order to protect wood from rotting, BBK-3 and GR-48 are also often used.
BBK-3 is a solution of borax and boric acid. It is relatively safe for people and animals, and also has excellent penetrating ability.
GR-48 is a drug based on pentachlorophenol. It protects the boards not only from the negative effects of moisture and biodegradation, but also from blue stains.
Often, products are used that contain several active ingredients at once - for example, HTC based on chrompic and zinc chloride. However, this impregnation has 2 significant disadvantages: toxicity and the possibility of wood staining.
Oily and pasty antiseptics
Oily antiseptics are considered the most powerful of their kind. They are used to protect wooden walls from the negative effects of moisture and soil. However, oily impregnation also has two serious disadvantages: sharp unpleasant smell and the ability to color wood dark brown.
Paste antiseptics consist of three main components:
- Water-soluble antiseptic.
- Filler.
- Clay or bitumen as a binder.
Organically soluble antiseptics are products like PL containing pentachlorophenol and petroleum products. However, due to their high toxicity, they are rarely used.
The use of organically soluble antiseptics is justified for treating wood when exposed to moisture in order to avoid drying. Using these tools, you need to take care of personal protection: gloves and a respirator.
How to apply impregnation to wood
In order to treat wood with an antiseptic composition, use different methods. Most effective way immersion of the material in baths with the active substance is considered. The only disadvantage of the method is its high cost.
The second method is impregnation using autoclaves. This method is based on the effect high pressure, which contributes to the deep absorption of the composition into the material.
Often special pastes are applied to the boards - they have good penetrating ability and effectively protect the material from fungus. Antiseptic agents are often applied using rollers, brushes, or simply sprayed from a spray bottle.
Applying an antiseptic with a brush, as well as a spray gun It is always necessary to apply the composition to a dry surface that has not been coated with varnish or enamel, since in these cases the product will not be able to be absorbed.
The first step is to treat the areas where rotting has already begun. Usually these are the ends of the building and sections. It is best to carry out the procedure at a temperature from +20 to +25. If the temperature drops below +5, treatment with an antiseptic will not work.
Folk remedies for impregnation
If the putrefactive process has not had time to grow significantly, folk remedies will help prevent further destruction of the tree:
- Silicate glue.
- Soda and vinegar.
- Potassium dichromate solution.
- Copper sulfate.
- Resin.
- Salt and boric acid.
The easiest way is to use silicate glue. It is required to dilute it with water, and apply the resulting solution to areas where biodegradation is observed. You can also treat the places of decay with soda, and sprinkle with vinegar from the spray bottle on top.
Potassium dichromate is used by mixing in equal proportions with sulfuric acid. The resulting composition should be processed not only on the boards on the street, but also up to 50 cm of the soil layer.
Another effective one improvised means to prevent wood rotting – copper sulfate. To prepare the composition, take 100 g of the substance per 10 liters of water.
For external processing resin can be used, as well as a mixture of 1 kg of salt and 50 g of boric acid, which are stirred in 5 liters of boiling water. Such a composition must be applied to the wood several times, waiting for a couple of hours so that the product can be absorbed.
Processing by the Finnish method
The Finnish method is a special way of processing wood to protect it from moisture and decay. You will need a set of ingredients:
- salt;
- flour;
- water;
- slaked lime;
- inkstone.
This composition stays on the material for a very long time without being washed off with water. Despite the safety of the method, it is recommended to use it only for the protective treatment of wood intended for fences and roofs.
The listed ingredients must be mixed to a consistency reminiscent of sour cream, and the main part of the mixture should be based on flour and water. After thorough mixing, the composition should be slightly warmed over low heat, and when it becomes warm, you need to quickly apply it to the boards.
After the first layer has dried, it is necessary to process the material again. If the composition has cooled down by this time, it will need to be heated again.
Wood is the building material, which has high thermal and mechanical properties. Valuable structural qualities - light weight, strength, industrial production of building parts, transportability - determine the economic feasibility of using wood in construction.
However, wood also has one big disadvantage: under certain conditions, it can be destroyed by biological agents (insects and wood-destroying fungi). In addition, wood staining and mold fungi may appear on wooden structures. These organisms do not destroy wood, but can significantly damage it appearance.
Thus, molds paint the wooden surface an unpleasant dirty green color, and wood-staining ones - yellow, blue, brown, reddish, etc. Blue discoloration especially often appears on the wood, which is also a sign of damage by wood-staining fungi.
As a rule, it appears on sapwood when raw wood is stored in warehouses, slow drying, or in finished houses from insufficiently dried or damp logs (see Figure 1).
Figure 1. Manifestation of blue on wall logs
Blue stains can affect wood of any species, most often coniferous. Infestation by blue fungi begins from the surface. Penetration into the wood occurs along the core rays. For example, on rounded ends the blue forms radial wedge-shaped spots; sometimes there is a solid color of the sapwood (see Figure 2). Elongated spots and stripes of blue are observed in the lumber and on the side surfaces.
Figure 2. Damage to blue sapwood of pine wall logs
The optimal temperature for the reproduction and growth of blue fungi is considered to be 20-25 degrees; at 7-8 degrees the growth of the fungus slows down. As for humidity, the optimal range is considered to be 33-82%, but wider limits are possible (from 22 to 163%).
Blue-stained wood usually has an increased rate of water absorption. After the influence of blue fungi on wooden structures for a month, the rate of water absorption of the sapwood of pine wall logs increases by one and a half times.
Wood affected by mold fungi does not actually change its technical properties, however, a damaged appearance reduces its value. Blue fungi and mold are the primary complex of destroyers, which, with prolonged exposure, create a favorable environment for the further development of house fungi, which are especially dangerous for wood.
Wood-decaying fungi cause great damage to wooden structures of structures and buildings, sometimes completely rendering them inoperable. Such damage is associated with the colonization and development of house fungi in wooden structures. Today, more than 70 species of such fungi are known, many of them capable of causing local damage. They destroy wood rather slowly and are of little practical importance.
Wood rotting is natural process decomposition, which is characteristic of any dead plant. Wood decomposition occurs due to wood-decaying fungi. These are lower plant organisms that penetrate deep into the wood and use its components for their development.
At favorable conditions spores (fungal embryos) begin to germinate, turning into hyphae, that is, mushroom threads.
Enzymes secreted by developing fungal threads partially dissolve the walls of wood cells. They are used by fungi for growth and nutrition. This is how rotting occurs - the biological resolution of wood.
During the initial stages of decay, wood does not change its appearance, so the presence of fungal threads can only be detected under a microscope. Later, the wood becomes reddish or yellow, then brown and brown, its strength and density gradually decreases, it loses viscosity, becomes soft and light. At the last stage of decay, transverse and longitudinal cracks, according to them it will break up into separate prisms. The properties of this wood are similar to charred: with light pressure it is ground into powder. This type of rot is called destructive. It is characteristic of house fungi, which destroy structures in structures and buildings (see Figure 3).
Figure 3. House mushroom variety Merulius lacrymans (Fr.) S.F. Gray:
a – mycelium; b – young fruiting body;
c – old fruiting body; d – appearance of old mycelium, rot and wood cords
Mandatory conditions for the development of wood-destroying fungi are:
- Sufficient wood moisture (more than 20%)
- Availability of food
- positive temperature.
If any of these conditions are absent, the development of the fungus will be delayed, even if it has taken root in the wood. The humidity and temperature of wood that are needed for the growth of house mushrooms are given below.
Table 1
| Type of house mushroom | Temperature, °C |
Wood moisture content, % |
||
| minimum | optimal | maximum | ||
| Real | 8 | 23 | 27 | 20 |
| White | 5 | 27 | 37 | 35 |
| Filmy | 8 | 23 | 37 | 50-60 |
Most great harm The following types of fungi can cause damage to wooden structures: white brownie, true white, filmy brownie.
Various means are used to combat wood rot: chemical measures protection that is based on the use of biologically active substances and drugs. They are able to prevent the development, weaken or stop the vital activity of organisms that cause damage, sometimes to the point of complete destruction, of objects, individual designs or materials.
Protecting a wooden house from biodestruction can be done chemicals and drugs called antiseptics.
Depending on the service conditions of the impregnated material, its purpose and type protective composition It is customary to use two different types of impregnation in construction:
- Antiseptic when the composition is applied to the surface. This ensures penetration of impregnation into surface layer wood 1-2 mm deep
- Canning or deep impregnation, in which the applied composition penetrates to a depth of about 2-3 cm or more.
If protection of a wooden house from biodestruction produced by antiseptic chemicals have a short-term toxic effect on destroyers. When canning, antiseptics have a long-term poisoning effect on destroyers.
The bulk of wooden structures used on construction sites, as well as in wooden house-building enterprises, are treated with antiseptics using surface application.
Deep impregnation is used mainly in woodworking shops of enterprises and impregnation plants.
You can buy wood preservatives from the manufacturer Skolt; in general, antiseptics have a fairly extensive range, and can be selected individually according to the request of each client. This diversity is caused by different operating conditions of wood, availability of chemical resources, availability of chemical resources, economic and safety requirements.
Below are tips for choosing antiseptics that will provide preventive protection of a wooden house from biodestruction. It can be used in residential buildings, garden houses, cottages.
Floors
In residential buildings, three types of floors are used: interfloor, basement, and attic. For interfloor and basement floors, common sources of moisture are leaks due to faulty plumbing fixtures and household moisture.
Basement ceilings
The moisture content of wooden structures in the underground is influenced by the level of soil moisture under the building. At waterproof soils, where there is surface water, as well as in wet soils that are permeable, strip foundations remain in a wet state. This causes capillary wetting of the soil base of the underground and masonry brick plinth. If the strip foundation is solid and the soil moisture is high, the air humidity in the underground also increases. This leads to the settlement and development of wood-destroying fungi on the floors.
Moisture that evaporates from the soil can be removed from the underground using vents installed in the basement. This allows you to ensure normal humidity conditions for basement structures.
In the first half of summer in middle lane the concentration of water vapor in the underground is actually no different from the concentration that is in the outside air. At this time, there is practically no diffusion release of moisture from the underground.
During this period, moisture cannot be removed by air flow, which only occurs during gusts of wind, since the moisture capacity of the air in the underground and outside is almost the same. It is at this time that wood rotting processes occur.
As a rule, a warm basement floor is installed over a cold underground, and load-bearing beams are most often placed inside the ceiling between the floor and the firmware. They can also partially extend into the underground space (for example, when installing a subfloor along the cranial bars).
In any case, it is necessary to take into account the possibility of wood-destroying and mold fungi appearing on the wood. You should also take into account the difficulty of monitoring the condition of the wooden floor. That is why before carrying out installation work It is recommended to treat all floor elements with antiseptics - beams, purlins, subfloor panels and boards, finished floors and joists (see Figure 4). Particular care must be taken to antisepticize those elements that are located in the thickness of the ceiling and are not subject to regular visual observation (see Table 2).
Figure 4. Basement floor on beams and outer wall from round timber:
1 – ventilation duct; 2 – gasket for thermal insulation (tarred tow); 3 – frame crown; 4 – lighthouse batten every 60 cm; 5- boards external cladding; 6 – flooring boards; 7 – logs; 8 – insulation; 9 – load-bearing beam; 10 – vapor barrier; eleven - support boards; 12 – subfloor boards; 13 – support lining; 14 – column made of concrete or brick; 15 – cranial block; 16 – waterproofing; 17 - blind area
To perform antiseptic treatment, it is recommended to buy BIODECOR or BIODECODER-M. These antiseptics are highly effective against wood-destroying and mold fungi, blue stain, insects, and have increased resistance to leaching. Antiseptic BIODEKOR-M does not corrode non-ferrous and ferrous metals. If you buy BIODECODER-M and process wood with it, it will acquire a pleasant light green tint. When using the BIODECODER, the wood is painted chestnut. These antiseptics do not hide the texture of wooden structures and are odorless.
Interfloor ceilings
Most often, the cause of rotting of wooden structures of interfloor ceilings is the use of raw wood and the lack of proper conditions for drying.
In beam-type ceilings, the ends of the beams located in the places of their contact with external stone walls (gas silicate, brick, foam concrete, etc.) are particularly dangerous. They can be moistened by condensation that forms in winter time on back wall nests due to influx warm air from the room, as well as installation moisture.
Repeated examinations of buildings with wooden floors have shown that the ends of beams located in external walls can be destroyed due to rotting or damage by insects and fungi (Figures 5 and 6).
Figure 5. Wood that is destroyed by wood borers and wood-destroying fungi (supporting part of the floor beam)
Figure 6. Destruction of the edge of a wooden floor beam (a) and a knurling plate (b) by house fungus
When beams come into contact with external stone walls, blind sealing of the edges of the beams is widespread (Figure 7).
Fig.7. Blind sealing of the beam in contact with the outer wall:
1 – floor beam; 2 – wall of the structure; 3 – the surface of the beam, which must be treated with an antiseptic; 4 – moisture-proof bandage; 5 – plaster for thermal insulation; 6 – waterproofing; 7 – foam for installation; 8 – wooden lining treated with antiseptic; 9 – waterproofing layer
When antisepticizing, the end of the beam must be beveled at an angle of 60-75 degrees, then the end of the beam, including the end itself, should be treated with a substance for a length that exceeds the depth of the structure by 15-20 centimeters. Based on the fact that the supporting part of the beam is exposed to drop-liquid moisture, BIODECOR-M, which is difficult to wash out, is used for processing.
The end should be especially carefully protected, since it is most often exposed to decay. The structure is treated with an antiseptic until completely saturated, that is, until the moment when absorption stops. Then the treated surfaces, except for the end, must be protected from moisture with the help of pasted waterproofing (you can use stekloizol, hydrostekloizol, etc.).
Those surfaces of the beams that are in the span are operated in more favorable conditions than the ends in contact with the stone walls. However, it must be taken into account that during operation water may get on them. These can be accidental leaks as a result of a breakdown in the sewer or plumbing system, heating devices etc.). That is why their antiseptic treatment is advisable. For this purpose, DOMOVOY antiseptic can be used. This drug has high diffusion ability. It penetrates deep into wood with high humidity, which allows the product to be used to protect damp or poorly dried wood. After treatment with this tool, the wood retains its texture and does not change color. It is important that DOMOVOI does not corrode ferrous metals, therefore, contact of the treated wood with metal structures, details.
For the protective treatment of various wooden floor elements, antiseptic preparations KRAM-S and KRAM can also be used. They are intended for impregnation of wood, which during operation is not subject to condensation moisture (see Table 2). These antiseptics provide multifunctional protection for wood structures, including helping against biodegradation and providing preventive protection against insects. KRAM-S does not change the color of wood, but KRAM paints it light brown.
Attic floors
When installing floors on beams, it is necessary to take the same measures to protect the edges of the beams as when installing interfloor floors (this can be treatment with the BIODEKOR-M antiseptic with further waterproofing of the protected side surfaces).
Figure 8. Contact points between attic floor beams and rafters on the outer wall
1 – window/door frame;. 2 – outer wall; 3 – plaster for thermal insulation; 4 – surf; 5 – cladding material for the eaves overhang; 6 – sheathing; 7 – roofing sheets; 8 – rafter leg; 9 – filly; 10 – mauerlat beam; 11 and 12 – waterproofing; 13 – supporting edge of the beam; 14 – load-bearing beam; 15 – blind sealing with cement; 16 – vapor barrier; 17 – insulation; 18 – reeling boards; 19 – cranial beam; 20 – filing boards; 21 - lining
You also need to consider measures to protect wooden floors from moisture from precipitation that penetrates into the attic through holes in the roof, as well as from condensation that forms due to freezing in the thickness of the floor.
Through the attic floor, in the same way as through other external fencing, diffusion of water vapor from the premises into the attic occurs. That is why, in order to protect the insulation from humidification by internal air vapor, it is necessary to protect it with a vapor barrier layer on the “warm” side (Figure 8). High-quality heat and vapor insulation will not only provide the necessary thermal protection, but will also significantly increase the durability of the rafter and roofing material. If the vapor barrier is missing, damaged or poorly installed, water vapor will be able to penetrate through the ceiling into the attic and flow onto the wooden beams. As a result, corrosion of metal parts and ceilings develops, destruction of rafters and roofing carpet.
If the tightness of the vapor barrier layer is broken, the insulation becomes moist and, accordingly, the heat-protective characteristics of the ceiling decrease. Those floor elements that should be treated with an antiseptic are shown in Table 2.
To protect floors from biodegradation, antiseptic treatment with DOMOVOY, KRAM-S, KRAM antiseptics can be used as a preventative measure.
Elements rafter system(Figure 8)
The safety of rafters, trusses, racks, purlins, mauerlats and other elements of the rafter system largely depends on the temperature and humidity conditions that exist in the attic. It can be heated (attics) or cold (unused).
Cold attics
In winter, air with high moisture content penetrates through leaks in hatches and doors from living quarters into the attic. This causes intense condensation on the elements of the rafter system and cold roof surfaces.
It is necessary to pay special attention to the condition of the roof. Sometimes barely noticeable damage to the roof can eventually lead to the destruction of the supporting structure as a result of rotting (Figure 9).
To prevent biodestruction of rafter system elements, it is recommended that they be antisepticized with BIODEKOR-M, KRAM-S, KRAM. If on demand fire safety If you need to protect wooden structures from fire, you can use complex fire-bioprotective preparations FENAX, SENEGA-OB.
Figure 9. Destruction of the rafter leg by house mushrooms when the roof is damaged
Mauerlats that rest on stone walls must be placed above the attic insulation level by no less than three rows of brickwork. After treatment with antiseptics, it is necessary to lay rolled waterproofing between the masonry and the mauerlats.
Elements of the rafter system that are subject to mandatory antiseptic treatment are shown in Table 2.
Attic coverings
When installing attics, the insulated covering must be partially or completely combined with the roof. The basis for the durability of the combined coating will be the creation of a solid insulation contour around the perimeter attic floor, as well as ensuring good vapor and waterproofing around the insulation contour and its ventilation.
It must be said that insulation of a combined attic covering is considered a more difficult task than insulation wall covering. On the enclosing surface of the attic room, the condensation of water vapor contained in warm air is higher than in those rooms located on other floors of the building. Under normal conditions (air temperature about twenty degrees Celsius and relative humidity 65%) water vapor content is about 11.4 g/cub.m. the dew point will occur at 13.2 degrees. Under the attic ceiling, the temperature will be a couple of degrees higher than inside the room, so condensation will begin to form on those surfaces that have a temperature of 15-16 degrees.
As a rule, the insulation in the coating attic premises laid between the rafters. To produce insulation, glass and mineral wool slabs of sufficient density are used. In this case, all elements of the rafter system are located out of sight. Moreover, some of them, for example, rafter legs are partially or completely in the insulation layer. It is worth saying that this scheme allows rational use of the entire thickness of the coating, but it justifies itself provided that the work is carried out competently.
A large number of problems when installing insulation between rafters arise due to loose contact of the thermal insulation with the side surfaces of the rafter legs. If the gaps between the rafters and insulation are not sealed, which happens quite often, condensation will form. It appears on the surfaces of the rafter legs, as well as locally - in the area where the rafters are located and on the ceiling.
If the formation of condensation on wooden surfaces occurs systematically, they may be damaged by wood-destroying fungi. Considering that these processes take place secretly, they are detected only when the deformation of the rafters becomes noticeable.
This phenomenon can also be observed with insufficient use of insulation. In this case, in winter, the coating freezes, systematically moistening the wood, as well as the insulation itself, with condensate.
The above makes it clear that protecting the wooden parts of combined attic spaces from possible biodegradation is a mandatory measure.
It is necessary to take into account that visual control of the condition of the rafter system in such coatings is impossible; bioprotective treatment of wood is carried out with hard-to-wash antiseptics with a long service life. In this case, it is recommended to use the antiseptic drug BIODEKOR-M.
External wall logs and beams (see Figure 4)
The main reason for the premature failure of paving and log walls is their destruction by wood-destroying fungi. This is largely facilitated by shrinkage cracks, which become a kind of “gate” for fungal infection and atmospheric water to penetrate into the layers of wood. They cause internal damage to the timber or log (this is central rot).
Practice shows that in buildings made of timber and logs, rot most often affects the lower crowns.
What is happening can be explained by the direct impact of atmospheric precipitation on the structures, as well as the consequences of differential condensation, which is observed when wooden elements with large cross-sections are installed directly on a brick or concrete base without laying thermal insulation between them.
In spring, when daily fluctuations in outside air temperature are more significant, during the day the solid base warms up more slowly than wood. Due to the temperature hysteresis of the base and wood, condensation of air water vapor will be observed in the mass of wood at the point of contact with the base. As a result, internal (central) rotting of the lower crown may occur. This can be avoided using comprehensive (chemical and structural protection measures). It is worth saying that chemical protection measures come down to treatment with the difficult-to-wash-out preparation BIODECODER-M; it is applied in a specific way, which is called “wet on wet”. Shrinkage cracks must be filled with special care. It is advisable to use this method for those lower crowns of logs that already have formed cracks. Otherwise, when using insufficiently dried, damp logs, cracks will appear there after drying. They will tear the protective layer. This may lead to the nullification or significant reduction of the expected antiseptic effect.
To protect the cobblestone and log walls of a house from biodegradation and exposure to precipitation, they are often covered with decorative boards (this can be clapboard, land house, block house, etc.), sheet materials, siding. Brick cladding is also often used. The cladding is located at a distance of about 25 centimeters from the wall. This provides a drying regime for the structures. The air gap must be designed in such a way as to completely prevent precipitation from entering it. Ventilation occurs with the help of air entering under the casing from below and exiting near the eaves. In paving stones and log walls with brick cladding, the ventilated gap should be at least 5-7 centimeters.
Practice of construction, as well as operation of buildings with cladding of external walls of the house decorative board indicates that when laying the sheathing, wall beams and logs are in conditions where the possibility of the appearance of wood-destroying and mold fungi is either completely absent or minimal. When facing walls with bricks, the ventilation gap is often blocked by mortar, which falls down when installed brickwork. Because of this, an unventilated space is created between the cladding and the wall. In this case, the likelihood of mushrooms appearing on the surface increases significantly. That is why, for prevention, it is necessary to perform an antiseptic treatment of the outer surfaces of wall beams and logs before laying bricks. For this purpose, preparations such as BIODEKOR-M, KRAM-S or KRAM can be used (see Table 2)
External plank cladding of gables and walls
It must be said that it is necessary to protect the plank lining itself, both from the inside and from the outside. In many ways, the durability of the cladding depends on the profile of the board, its placement on the facade of the building, and the type of attachment to the frame. The sheathing boards are either horizontal or vertical. Each of these methods has its own advantages and disadvantages.
If the boards are positioned vertically, atmospheric water can flow freely along the fibers and linger only at the bottom. If the height of the base is insufficient, the cladding boards are subjected to increased moisture from slanting rain, melting snow and splashes from the blind area. The same can happen in the absence of ebb tides or with protruding plinths. In this case, the ends of the boards become waterlogged, which creates optimal conditions for biodegradation of wood. If rotting occurs, all boards will have to be replaced.
The version of the cladding arrangement with the boards placed horizontally also has its disadvantages. Experience suggests that in the case of horizontal boards, rainwater will drain much worse than from those boards that are located vertically. This is explained by the fact that during operation, the surface of the boards becomes fleecy (rough) over time, and small cracks may appear on it. This promotes moisture penetration into the wood. On horizontal boards, unlike vertical boards, mold or staining mushrooms often appear. They are mainly localized at the bottom of the boards, where there is more moisture.
Sheathing boards must be treated to prevent biodestruction, to make the surface of the boards decorative, and to reduce warping of the boards during operation. In this case, the outer surface of the boards is often covered with opaque or glaze coatings. After using such coatings, it is necessary to treat the surfaces of the boards with a tinted or colorless antiseptic primer. This could be SKOLTEX-PR. The drug is effective against blue stains, wood-destroying and mold fungi, and insects (Figure 10). SKOLTEX-PR has a high penetrating ability, therefore it can create a stable protective layer on its surface without forming a specific “film” or interfering with gas exchange. In addition, SKOLTEX-PR does not hide the texture of the material and increases the adhesion of protective, decorative and paint materials to wood.
Figure 10. Pine board after a year in a humid chamber:
On the right is the area that was not treated with a protective preparation, on the left is the area of the board that was treated with SCOLTEX-PR.
For preventive purposes, the reverse side of the cladding board should also be treated with the bioprotective agent SCOLTEX-PR. The preparations KRAM-S and DOMOVOY can also be used for these purposes. These compositions color the materials, and therefore, if the drug accidentally gets on the front surface, they do not leave any traces.
Load-bearing elements wall panels And frame walls classified as hidden structural elements. The condition of the wood can only be determined by indirect signs(for example, by the deformation of walls), since they are not subject to visual inspection. The main reasons for the appearance of wood rot in these walls is the regular condensation of moisture when the walls freeze due to insufficient thickness of the insulation or its settlement.
Figure 11. Basement and outer wall made of panels with a wooden frame:
1 – elements of the load-bearing frame of the floor panel; 2 – bottom trim (plywood, boards, etc.); 3 – insulation; 4 – floor covering boards; 5 – vapor barrier; 6 – load-bearing vertical edge of the wall; 7 - interior lining; 8 – external cladding boards; 9 – bars for fixing the casing; 10 – supporting edge of the wall; 11 – wooden rand beam; 12 – pile, columnar foundation; 13 – tarred tow; 14 – waterproofing; 15 – base covering; 16 – ventilation duct; 17 - blind area
If you follow the rules of structural anti-rot prevention, wooden frame walls and panels are special measures chemical protection from biodegradation will not be required. It should be taken into account that it is impossible to guarantee the absence of conditions for the formation of fungi inside the walls and on the wood. That is why antiseptic treatment of the wall frame, as well as panels, will not hurt (see Table 2). bars bottom trim walls, as well as supporting ribs of panels and rand beams must be treated with the hard-to-wash antiseptic preparation BIODEKOR or BIODEKOR-M. To perform biocontainment treatment on others structural elements panel and frame walls, you can use antiseptic compositions KRAM, KRAM-S, DOMOVOY. The main condition for bioprotective treatment with these antiseptic preparations on a construction site is the protection of impregnated wood from exposure to precipitation.
Partitions. Protective treatment Antiseptics are only necessary for wooden elements of interior partitions that are adjacent to concrete or brick external walls within a strip of half a meter. In bathroom partitions, racks, trims, and braces are subject to antiseptic treatment. The compositions used for their bioprotective treatment are given in Table 2.
Terraces, porches, balconies. During operation, balconies and terraces, depending on the design and architectural solution are exposed to varying degrees to natural influences, including precipitation. They lead to systematic moistening of the wood, which can lead to the appearance of wood-decaying fungi. Most often, bi-destruction of fences and decking occurs open terraces, balconies (Figures 12 and 13).
They can be protected using comprehensive protection, including impregnation of wood with a difficult-to-wash-out composition, followed by the application of a protective and decorative coating. Antiseptic treatment of wood can be done using the preparations BIODEKOR, BIODEKOR-M. To protect the surface from moisture use paint and varnish compositions on organic/ water based, protective and decorative preparations, their choice on the modern market is quite wide.
Figure 12. Destruction of a balcony fence by a house fungus, which does not have chemical and structural protection.
Figure 13. Damage to house fungus on balcony decking (this is a view from below)
Long-term and reliable protection of porch elements from rot, as well as loggias and balconies, is provided by BIODEKOR and BIODEKOR-M antiseptics. Considering that the most vulnerable to rotting are the lower ends of the pillars (chairs) 5 and the bed 1, which are in contact with the ground (Figures 14 and 15), they must be impregnated with an antiseptic composition to a sufficient depth. This is the most affordable and easiest way to process wood in construction conditions. Thus, it is possible to obtain high-quality impregnation by soaking wooden elements in an antiseptic solution for several days. To perform soaking, you can use a variety of containers. These can be bathtubs that are made of boards and lined with several layers on the inside. polyethylene film. To impregnate the lower ends of chairs that are installed in the ground, it will be useful plastic barrels(Figure 16). Other elements of the porch (girders, flooring, steps, stringers) are treated with an antiseptic. To do this, the composition is applied to the surface by spraying, brushing, or short-term immersion in an antiseptic composition.
Figure 14. Porch:
1 – lying down; 2 – stringer; 3 – steps; 4 – flooring; 5 – chairs; 6 - run
Figure 15. Installing a wooden post in the ground:
1 – pillar; 2 – end of a column impregnated with an antiseptic composition; 3 – roll waterproofing; 4 – binding wire
Figure 16. Impregnation of pillars that are installed in the ground:
1 – pillars; 2 – barrel; 3 – level of composition for processing; 4 – base
List of structural elements that are subject to biodegradation and must be subject to antiseptic treatment.
table 2| Houses made of timber (logs), frame and panel type | |||
| Constructions | Elements to be antiseptic | Antiseptic | |
| Rafter system (Fig. 8) |
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| Exterior walls | From round timber and timber (Fig. 4) |
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| Frame and panel walls (Fig. 11) |
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| Floors | Socle beam structure (Fig. 4) |
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| Basement panels (Fig. 11) |
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| Interfloor and attic (Fig. 1) |
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| Partitions |
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| Floors (Fig. 4 and 11) |
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| Window and door frames (Fig. 8) |
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| Terraces, balconies, porch (Fig. 14) |
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Technical Director: A. D. Lomakin
The roof truss system is a wood material that is easily destroyed upon contact with moisture and quickly ignites in the event of a fire. How to treat rafters to extend their service life and prevent the formation of mold microflora. Which of the formulations available on the market is most effective? This depends on the type of wood and the prevailing climatic conditions. If it’s humid, you need protection from water; if it’s hot, you need to protect the wood from fire.
What should be the composition
Any tool that you decide to use to cover the truss system must meet the following requirements:
- penetrate deeply into the structure of wood fibers;
- do not contain copper sulfate, potassium bichromate, arsenic, chromium;
- dissolves well in water, but does not wash off from the tree;
- effectively protect floor beams and lathing from mold, rot, fungus, and prevent ignition.
After that, it is worth deciding what is more threatening to the rafter system - rot or fire. For humid climatic conditions, an antiseptic is chosen that will penetrate deep into the tree, and then additionally coated with a fire retardant. The fact is that wood can only be impregnated once. The strengthening of the properties of wood to resist the formation of rot or fire depends on which composition is applied first.
What are the types of antiseptics?
Antiseptics for floor beams and sheathing may have additional decorative effect. The composition of the products includes alkyd resin, which gives the wood specific color. For the rafter system, water-soluble antiseptics are most often used. They have a number of advantages:
- penetrate deep into the wood structure;
- they are easy to apply to elements of the rafter system;
- dry quickly and allow the wood to breathe;
- form a moisture-proof film on the surface of the wood.
High-quality antiseptics should have antimicrobial (biocidal) and antifungal (fungicidal) properties, as well as provide reliable protection against insects - insecticidal properties.
Water-soluble substances mainly contain sodium fluoride and silicofluoride, a mixture of borax and boric acid, pentachlorophenol, a mixture of zinc chloride with sodium (potassium) chromium peak. The compounds are toxic only to microorganisms and are completely harmless to humans. There are also products that are soluble in oil, petroleum products and light solvents.
Methods of applying antiseptics
Impregnation (surface impregnation with an antiseptic) is performed by completely immersing wooden elements in the composition or by applying the substance with a spray gun / ordinary brush. For immersion, a special bath, trough or even a ditch is used, after lining the container with plastic wrap.
The immersion time of the material depends on the specific antiseptic. Typically, the manufacturer indicates on the packaging 30-60 minutes for small and medium-sized wood. When immersing large trusses, for example, for a roof made of natural tiles, the impregnation time is increased to four hours. After drying for 24 hours, all ends of wooden structures are treated.
When treated with an antiseptic manually by spraying, sprinkling or staining, the effectiveness of the penetration of the composition deep into the wood is markedly reduced. Although this method requires a small amount of antiseptic composition.
The coating is carried out in several layers with an application interval of about half an hour.
The most popular antiseptics
Has proven itself in practice modern remedy Senezh. This antiseptic can be used to treat the roof, wooden sheathing, floor beams. The composition is presented in the form of a ready-to-use water-based solution. Its advantages: 
- bioprotection for a period of 30-35 years;
- type of composition – difficult to wash out;
- chemical bond with wood;
- penetrates deeply into the fiber structure without increasing hygroscopicity;
- allows the tree to breathe;
- has a decorative effect.
The recommended consumption is 250-300 g/m. cube when applied without immersion, 60-80 kg/m. cube when soaking. Senezh penetrates deeply into floor beams and other elements, forming a two-level protective barrier. Prevents the development of fungi and mold microorganisms, insects. The manufacturer produces various series of antiseptics - Ultra, Bio, Thor, Sauna for specific wooden structures.
Estonian-made Pinotex Impra is highly effective. Suitable for bioprotection of floor beams, sheathing, mauerlats, rafters. It is a water-based antiseptic with an alkyd binder. Deeply absorbed into the wood surface, provides good protection from rot, blue stains, mold.
The consumption of the substance ranges from 85 to 200 g per square meter depending on the wood processing – sawn or planed. Pinotex Impra cannot be used for elements of the rafter system already affected by microorganisms, unlike the Senezh composition.
The product produced in Russia, Drevotex, is used to protect wood material from the formation of rot and mold. Main characteristics:
- effectively protects floor beams and boards from exposure to atmospheric moisture;
- the bio series is suitable for the prevention of healthy wood material, the anti-mold series is used for wood affected by focal microorganisms;
- type of impregnation – difficult to wash out, allows the wood to “breathe”;
- the bioprotection period of the rafter system with the complex agent Drevotex is about 30 years;
- product consumption is 250-350 g/sq.m. m when brushing and 200 kg/m. cube when immersed.
The product can be applied to new wood or as a treatment for existing roofing structures.
When choosing antiseptic compounds for floor beams, sheathing boards and mauerlats, it is necessary to pay attention to the moisture content of the wood, since not all antiseptics are suitable for wood with a moisture content of more than 20 percent.
Application of fire retardants
Fire protection is designed to give wood material additional qualities - fire resistance, reduced flammability. If you decide that the likelihood of a fire is higher than the possibility of rotting truss structure, first of all, all wooden fragments of the roof should be treated with fire retardants.
They are classified into the first and second efficiency groups. The products of the first group provide fire protection for 5-7 years, so they are more effective. Most fire retardants are based on ammonium phosphates and sulfates, borax, boric acid and combinations of these substances.
All fire retardants are divided into:
- Impregnations are solutions of salts that are applied manually or by immersion.
- Coating fire retardants have a paste-like consistency.
- Varnishes are used for decorative purposes. Their use on the roof is unnecessary.
- Paints form a thin protective film on the surface.
Most often, to protect floor beams and rafters, impregnation is used, when the fire retardant will serve as the main protection, and coating, if the fire retardant is applied to the antiseptic. The methods of coating with fire protection are identical to the application of antiseptics. The market offers a large selection of compounds of the first and second categories. Neomid is very popular.
Since the composition has received a lot of positive customer reviews, we can take a closer look at its properties.
Neomid 530 – fire protection
The product is suitable for any type of wood surface - sawn or planed floor beams, boards, rafters, sheathing. Main advantages:
- fire protection for ten years;
- has antiseptic properties;
- does not contain toxic substances and formaldehyde;
- does not interfere with further processing of wood;
- does not change the hygroscopicity of the material;
- supplied ready to use;
- made on a water basis;
- in terms of danger to humans, it occupies the same category as household chemicals, - not dangerous.
Neomid compositions are available in different series. Some products are designed to protect floor beams and other elements of the rafter system from insects, rot, blue stains, and are used as wood bleaches. Neomid 530 is an effective fire protection that is currently the most popular.
Before processing rafters, you need to choose the right protection priority. The composition that is applied first will be the main one. The second substance will perform an additional protective function.
Wooden floors between floors are suitable for almost all types of buildings. They are compatible with wood, brick and concrete buildings. Structures are installed not only between floors, but also in attics and basements. You can’t do without them in these rooms, but the arrangement of wooden floors between floors differs from basement structures.
Features of wooden floors
The ceiling structure includes, for the most part, only wooden elements. However, absolutely any materials are used to finish the ceiling and floor. The main thing is to correctly install the structure itself.
One of the most important functions of flooring is sound insulation. It is very easy to attach any insulating materials, including slabs. You can easily install any modern finish on top.
Very important advantage wooden structures - light weight. Wooden floor elements do not exert significant pressure on the base of the building. Therefore, they are often used in houses with light foundations.
Installation carried out according to the rules promotes natural air exchange in the room. At the same time, the heat and sound insulation of the rooms is not compromised.
In general, wooden structures are very durable. They allow you to create lightweight and durable floors in a short time.
Technical requirements for floors
Interfloor structures consist of the following elements:
- beams;
- bars;
- layer of board;
- heat and sound insulation layer;
- waterproofing film;
- finishing board;
- ventilation slot;
- baseboards.
Note! Wood belongs to the class of highly flammable materials. In addition, it is susceptible to putrefaction, fungi and various bacteria. Therefore, materials for floors must be processed before installation. The minimum set of impregnations consists of fire retardants and antiseptics.
Installation and processing
To do the right thing wooden floor between floors you need to figure out the structure of its structure with your own hands. It consists of a beam frame and sheathing made of boards or sheet particle materials.
The role of a heat-insulating and sound-proofing layer is performed by rolled material. Most often, glass wool, mineral wool or similar insulators are used for this. Sometimes expanded clay or polystyrene foam is used. However, the first one makes the structure very heavy, and the second one is highly flammable.
For wooden floors between floors in saunas and baths, it is very important to properly arrange waterproofing. In this case, vapor-proof films are optimal, allowing moisture to pass through only in one direction. The material consists of expanding cones that absorb moisture only from the porous side. No moisture is released from the reverse side of the coating.
Important! Vapor-tight coatings are laid with the porous side facing the insulation, “facing” the room. And for the room above, the film is mounted in reverse.
Floor beams
To figure out how to make a wooden floor between floors, you need to know the features of the structure's frame. Its basis is wooden beams. Most often, elements 15-25 cm in height and 5-15 in thickness are used. There is a distance of up to 1 m between the beams, depending on the cross-section of the elements.
Note! The greater the load on the floor, the larger the cross-section of the beams should be.
The supporting ends are made from 150 mm in length, they are laid using the “beacon” method. First, the outer beams are installed, and intermediate beams are laid between them. The evenness of the installation is checked with a level. The middle beams are laid according to the template. For leveling, you can use various resinous pads from scraps.
Important! You cannot use hewn, pointed wood chips to level beams.
The beams are laid with the same spacing along the entire perimeter, strictly parallel. Before laying, they are treated with antiseptic impregnations and wrapped in 2-3 layers of roofing felt. For brick and block buildings, floor beams are coated with bitumen at the ends. This technique protects the wood from moisture. For walls with a thickness of 2.5 bricks or more, vents are left for ventilation. And at the junction of the wood and the walls, roofing material is laid under the beams.
Reel installation
To cover the floor between floors use various materials made of wood, including boards, plywood and particle boards.
The subfloor in the ceiling is the lower flooring; it is on this that the thermal insulation material. It can also be attached directly to the beams from below. In this case, it performs the function of a rough ceiling, onto which finishing material can be immediately mounted. A floor made using second-rate boards will cost several times less.
The distance from the beams or logs is determined by the thickness of the boards with which the rough covering is covered. They bear the main burden. So, if boards of 2 and a half centimeters are used indoors, a step of 50 cm is needed for attic spaces, and 40 cm for residential spaces. Therefore, it is recommended to use a thick board of 4-5 cm for flooring.
Methods for laying basement floors
For wooden structure a cranial block is required for the base. It will allow you to insulate the floor. After all, it is on this that the panels or board covering the insulation are mounted.
The more popular option is a rough layer of rolled or unedged boards. The material is mounted on wooden block with a square cross-section and a side of 5 or 4 cm. It is best to attach the cranial beam to the logs with self-tapping screws, but you can also use nails.
Advice! You can attach the board not to the skull block, but to a groove (quarter). It needs to be cut with chisels or power tools. It will take longer.
The subfloor of the basement is insulated with bulk materials, including sand. Antiseptic-impregnated sawdust or mineral wool from 10 cm in thickness. To protect wood structures, a waterproofing layer is laid underneath. Most practical option- bitumen rolled materials. For rooms in contact with moisture, waterproofing is also installed on top.
Insulation and sound insulation
The thermal insulation layer is very important in the design of the ceiling: it performs the function of sound insulation. Therefore, modern synthetic and mineral insulation. They are not susceptible to bacteria and fungi, so they have a longer service life.
Mineral wool is very popular. However, some rolled materials are contraindicated for baths and saunas. It is not recommended to use slag wool in such rooms, as it contains suspended metals. These particles rust from moisture, and the cotton wool sags, losing its properties.
Most often, in rooms with normal humidity, roofing felt is used for waterproofing. Bituminous materials have low cost and excellent performance characteristics. Thick polyethylene is laid on top of the roofing material.
Thermal insulation material is mounted on top of the film. It is very important that there are no gaps between the layers of cotton wool or polystyrene foam, otherwise the room will have low heat and sound insulation. If used slab insulation based on foam plastic - the cracks are sealed with polyurethane foam.
By installing the floor of the second and first floors on wooden beams, you can save a lot. Such structures will cost several times less than concrete ones, and you can also handle the installation yourself.
During work, certain rules must be observed. For example, it is necessary to use beams of a certain section, and the pitch must be adjusted taking into account the floor area.
