What to do if the boards have darkened from moisture. What to do if the timber or boards turn blue and black? The company "Housing Construction Center" monitors the quality of materials

In total, there are about a hundred species of marsupial fungi of the genus Ceratocystis in nature, which stain certain species. tree species in blue color. In wood protection guides, the term blue or chemical color is used to refer to such fungi.

The most famous blue of the pines, which colors the lumber sawn from pine in a bluish-gray color. Pine lumber begins to turn blue when wet and warm weather sets in, when the average daily temperature is above + 10 ° C, while for blue to appear, wood moisture content of more than 20% and poor ventilation. For the Ural region, this time usually comes at the end of the May holidays and ends with the onset of the first frost, so it is more advisable to purchase lumber for construction in the winter.Purchased lumber is stored at the construction site in piles on spacers, i.e. each row in a stack for better ventilation separated by spacers. Such stacks of lumber are very well ventilated during the spring months, and by the beginning of the construction season you get dry lumber with a moisture content of about 18%, which is no longer afraid of blue.

Blue lumber with a moisture content of less than 20% humidity is quite suitable for construction purposes, the strength of such lumber does not deteriorate, it is also noted that when such wood is painted or coated with any compositions, the absorption of such wood is much higher. However, it should be remembered that it is necessary to prevent the recurrence of suitable conditions for the growth of the fungus, since the process of blue development will be started again.

Blue on wood can also develop in an already built house, again if there are favorable conditions for its development. As a rule, if blue develops inside the house, then this first of all indicates very poor ventilation of the rooms in the house, excess moisture is not removed, thereby contributing to the development of blue, and then the appearance of mold.

During normal use of a house built using lumber, the wood inside the building has a moisture content of about 6 - 12%, and on the outside of the house, such as the roof area, the edged board has a moisture content in the range of 15 - 18%. It follows from this that, only for very complex weather conditions(rainy season, flood) and poor ventilation, wood moisture in such areas can exceed 20% level.

If you have a wooden house or boards from which you are going to build a frame house, then you may encounter such a problem as changing the color of the boards for a variety of reasons.

Certainly, boards blacken not only in frame houses, but also in any other wooden houses blue may appear on the boards, but since we are talking about skeletons, I will tell you about them.

So, if your boards have darkened, you must determine what color they have become in order to understand whether it is weathering (blue) or rot. If the blue is on the boards, then the boards are simply weathered, this will not affect the strength. But if the board is blackened, then something needs to be done about it.

If blackened board- it's a mold, or more precisely - a fungus.

For what reasons does the board blacken in a frame house?

The main reasons for the blackening of the boards just three:
1. Systematic waterlogging of boards;
2. Insufficient ventilation of the boards natural humidity in the course of their drying;
3. Misformed knots frame house:
- Incorrectly installed films in frame house(about correct installation films, read), which leads to the locking of moisture in the boards.
- ventilation gap is not made in or there is no waterproofing of the facade
- air ducts are incorrectly made in and other similar problems.

But that's just the first part of the problem. main reason blackening boards is finding boards in conditions where they cannot dry out. Moisture is not terrible for a tree if it is then completely dried. If the board is left in a humid atmosphere, then mold may gradually appear on the boards, and the board itself may rot.

What to do with blackened boards?

Stage 1. Remove and whiten
If you don't want to inhale mold in a frame house (often airtight until vented), then remove your boards (if they are already installed). Now we bleach with some kind of whiteness or other chlorine-containing liquid. Before this, you can cut the board a little if the blackening is very strong.

Stage 2. Dry
Now lay them out with gaskets in a pile, let them dry (there should be a roof on top, do not close from the sides).

Stage 2.1. Rinse
Between bleaching and applying an antiseptic, it is imperative to wash the treated surface. Read more in the comments.

Stage 3. Antiseptic
After drying the boards, they must be thoroughly antiseptic. How to antiseptic: Senezh Ultra, Rogneda Biosept Ultra, Senezh Neo, Rogneda Frost, Neomid 500 and other potent antiseptics.

Is it possible to use blackened boards in the construction of a frame house?

After these 3 steps board can be used, it is better in not the most responsible places (that is, it should not be in the rafters and the floor).

And if the boards are not black, but white mold, then you can throw them away or burn them. This is already internal decay of the middle, the tree becomes less strong, it can no longer be saved.

By the way, if there is blue mold on the tree. Most likely this is a blue color caused by special fungi. They do not affect the strength of the tree, but only the aesthetics. It is not necessary to remove them. At most, they can damage protective covering on this tree (paint, etc.), so that they should only be used in places that are untreated and not visible to the eye and preferably ventilated.

Stay in touch!

The eternal problem of freshly sawn material or the main questions of customers. How to store material? Correspondence example:

QUESTION client:

A stack of new, bought pine boards lay for 2 weeks, after some of the boards went black and blue spots. The boards lay on sleepers laid on the ground, each layer was laid with a bar. In each layer, the boards were laid with a gap of 1-2 cm, during the rain they were covered with a film.
Tell me, please: What is this black and blue disease and is it possible to “cure” pine?

ANSWER TorgLes-a:

Hello Dear Client!
I have been manufacturing and supplying lumber for 15 years. I sell lumber at the Slavic World market.
Your mistake was that in dry and hot weather the wet board remained closed, thus the greenhouse effect and the board turned blue. In fact, this is a common headache, as a seller as well as a buyer. Because the suppliers do not comply with any standards, because the harvesting technology and GOST are becoming a thing of the past as the Union.
A freshly felled and sawn tree will definitely turn blue. That is, we are talking about a violation of the harvesting technology, since a sawn tree in a round timber must be left to winter, when temperature regime does not rise to -10 degrees Celsius. That is, moisture is removed by freezing by squeezing out of the pores - in a natural way.

Winter Wood- the most favorable for construction, because it has a lower percentage of humidity and is further less susceptible to the effects of fungal bacteria, i.e. it does not turn blue.

Tree felled in spring and summer- does not freeze and has high humidity. The board and timber starts to turn blue despite the fact that you laid it out on gaskets and covered it, moreover, even when transporting it to the customer’s construction site in a car closed type the material may darken in places.
Especially a small board with a cross section is subject to this process, sometimes very rarely.

Because of this, disputes often arise between the supplier and the customer. Many capricious Citizens are not in the house that darkening is a property of freshly cut and sawn pine material and does not lose its building functions as a board or timber material.

Sometimes when sawing logs, it becomes clear that the forest is blue in the bud. I, as a supplier, consider this issue as a loss of presentation, the only question is the price. Moreover, we dissolve it as a 2nd grade, i.e. we leave one working surface (we maintain the size in width), the other comes out ashed. Because this board has no special claims to quality and goes to rough work.

FALSE sellers and suppliers:

By the way, the approval of many sellers and suppliers edged lumber that they are selling winter wood in the midst of "Building Season" is a "FALSE". As a rule, by mid-July-August, wood harvested in winter from suppliers who serve large metropolitan areas ends. And then goes to the case "SVEZHAK". That is, a tree after cutting down in a round timber is immediately delivered to a sawmill and sawn to the ordered sizes.

Why is this happening:

• because lumber of natural moisture is of biological origin and reacts with the environment.
• temperature fluctuations and humidity fluctuations during the whole time after processing into edged lumber naturally affect the external and internal state of the wood.
• shavings that remain after sawing on a beam or board first begin to rot and react with the environment and, naturally, with wood. From what the board or timber is covered with a green coating.
• from improper stacking.

This question has a simple and obvious answer.

Water-soluble antiseptics that protect against mold include sodium fluoride, sodium fluoride silico, ammonium fluoride silico, VVK-3, HHP and MCHC. Their solution is applied to the wood with a brush or by spraying.

I strongly recommend the obligatory septation of edged sawn timber of natural moisture from coniferous species, regardless of the season and the condition of the wood (the material has turned blue or completely white).

SENEZH "EFFO" - properties:

Deep bleaching of wood due to increased penetration.
- Intensive formula of the bleaching composition SENEGE EFFO based on an oxygen-carrying agent.
- SENEGE EFFO retains the effectiveness of bleaching during long-term storage.
- The whitening composition does not leave chemical burns on treated wood.
- Bleached wood is safe for humans and pets.
- Wood bleach SENEZH EFFO removes all types of surface damage to wood.
- Suitable for both indoor and outdoor use.
- The whitening composition withstands freezing without loss of properties.
- SENEGE EFFO self-neutralizes, does not form efflorescence on the surface.
- Wood bleach SENEZH EFFO is suitable for processing food wooden shipping containers.
- The bleaching agent has a pleasant lemon smell.

By the way, there are still a number of positive points.There is a "NATURAL SELECTION" of the board, i.e. it will be possible to find out which board and where to put it in the construction process, because some boards will be twisted in the sun and they can be put aside and used for rough work (formwork, scaffolding, subfloor, etc.), the rest of the boards, the longer they lie, the greater the “WEIGHT” as the material will gain.

The most popular material that is used when construction is started or, despite technological progress and the latest developments, is still wood. It is also related to his technical specifications, and with the fact that the cost of repairing an apartment in Moscow can become significantly less if wood is used, and not, for example, metal elements. Alas, the wood is subject to various damages and quickly becomes covered with dark gray spots and blue stains. In damp air and high temperatures, flying fungal spores quickly do their job. What to do? Should the affected material be disposed of or can it be salvaged? Let's try to figure it out.

Correct workpiece

Why does wood darken? In fact, everything is simple. Wood is a biological material that has its own specific moisture content. Microscopic spores of mold and fungus, freely moving through the air, settle in a nutrient medium and begin to multiply actively there. Unfortunately, this process cannot be prevented. During construction or when, for example, an office is being renovated, it is difficult to process wood. What to do? First, choose the right material. Winter wood is considered the highest quality. It is harvested at a time when the temperature environment does not exceed 10 °C. Such conditions naturally cause moisture to freeze out of the pores. Winter blanks have an optimal percentage of humidity - 10-12, or even 8%. Such wood is the least susceptible to infection by fungi and mold.

Due to the absence of natural freezing, wood harvested in the summer, due to the activity of the construction season, is sometimes immediately sawn and goes on sale. It is raw, and therefore its use threatens with trouble. Not only can blue spots appear on the tree, it can also become deformed. This is especially true for boards, since the smaller the cross section, the easier it is for the fungus to penetrate inside. Actually, that is why the blue on the beam is a rather rare occurrence.

Secondly, it is better to purchase aseptic wood, especially if the construction is going to be long or you are stocking up on material for future use. This material is completely soaked in a protective solution at the factory. A uniform layer is enough to prevent the spread of fungus on the surface of the product, which significantly increases its shelf life.

You can also impregnate purchased boards yourself. To do this, you will need a sprayer, roller or brush. However, this is quite labor intensive. It is best to take a non-tinting antiseptic impregnation that does not form a film on the surface of the material.

The fungus that stains wood blue is not the only pest that can ruin building material. However, unlike other lesions, blue is dangerous symptom, since it not only penetrates deep inside, but also precedes decay.

Save or discard?

If the blue has settled on the building material or on finished construction, you need to get rid of it. The sooner you do this, the better. You can bleach it with special compositions. However, the first step is to dry the surface, ventilate the room - in general, do everything possible to get rid of excess moisture.

Wood bleaches are most often made on the basis of chlorine. For example, these are Neomid 500, Sagus +, Senezh EFFO. It is not always possible to remove blue from the first time. Therefore, the surface is usually re-treated. After bleaching, the wood should be washed. This is necessary to avoid efflorescence. Then it is dried. Only then can the result of the work done be evaluated.

It is important to bear in mind that bleaches are effective only in cases where the spores have not penetrated very deeply and have not affected the core. Sometimes it is easier to throw away building materials than to revive them. The penetration depth of the impregnations is on average 3 mm. If it can be seen with the naked eye that the damage to the wood is excessively large, if inside it is dark, almost dark and has a loose structure, then bleaching will not help in any way.

Potion for wood

Having performed the bleaching procedure, you can begin to apply a protective layer. For this, antiseptics are used. They may or may not form a film on the treated surface. The latter require regular treatment, since the biocide included in their composition is quickly washed out under the influence of precipitation. Antiseptics that do not form a film, as well as primers on wood, are applied before further painting (enamel, transparent translucent or completely covering moisture-resistant paint). They are also applied to wood, which will subsequently be closed. finishing materials in particular siding.

Primers penetrate quite deeply into the wood, they create a vapor-permeable coating and often contain UV filters. On the surface, they form an elastic coating that promotes better adhesion to paint or enamel. Among them there are those that can be applied to raw wood, the moisture content of which does not exceed 40%. Also, primers can cover parts of structures that will be constantly under the influence of adverse factors. Such compositions include Belinka base, AQUATEKS and primer-impregnation VDAK "On a tree".

The compositions that form the film not only protect the surface, but also create a decorative layer that gives the wood a pleasant shade. As a rule, manufacturers offer consumers about 10-15 colors to choose from. Antiseptics also protect the tree from fading and lightening.

For internal works primers and paints based on acrylate are used. Such compositions are distinguished by good thixotropy (that is, they do not drain) and do not have an unpleasant odor.

For outdoor use, it is best to choose solvent-based paints - alkyd azures. They will create a more durable coating.

When applying acrylate film-forming coatings, it should be remembered that their color appears only after complete drying. Alkyd, on the other hand, incorporate various waxes and oils, which provide a special coating strength.

So, in most cases, wood can be saved. However, no manufacturers of antiseptics guarantee that the blue will not return again. Repeated problems can be avoided if the wood is treated in a timely manner with appropriate compounds, monitored and cared for. So any building and structure will stand for a long time, delighting with its beauty and impeccability.

Blue and the appearance of signs of the development of mold formations indicate the emerging processes of damage to the fibers. The color of the mold can be different: the spores are blue, black, green, pink.

Lumber with such defects becomes unsuitable for construction. Knowledge of the causes, types and factors that influence the formation of mold, allows you to achieve prevention and elimination of the problem.

Causes of blue and mold

If the lumber began to change its natural color and there were signs of blue, this indicates the development of fungi in the fiber structure.

Detecting blue stain on a growing tree can be difficult, as the sapwood usually remains intact. Mold and blue become noticeable when cut.

The appearance of mold on sawn materials may occur as a result of incorrect storage, violation of the drying rules.

Conditions for the formation and development of mold fungi

The spread of mold fungi on the surface of a tree is facilitated by three conditions that are very comfortable for fungal microorganisms:

• the optimum temperature for their development is 25-27 degrees above zero, mushrooms are able to live at temperatures from 5 to 30 degrees above zero;
• with wood moisture content from 35 to 70%, fungi develop actively;
• organisms live in the presence of oxygen.

Mold fungi can penetrate the wood structure shallowly (a couple of millimeters). Affected areas are prone to increased moisture absorption and are more susceptible to rot and other types of bacteria.

Ways to protect against mold fungi

Given these facts, it becomes much easier to protect wood from fungus.

• Sawn materials are treated with protective compounds within three days after the saw cut. Only in this form they are stored.
• If the wood is in a high temperature of about 40 degrees above zero, the development of the fungus stops.
• Drying the wood also helps stop the mold infestation process. At a humidity of 25%, the formation of mold fungus slows down. At 15% humidity, the fungus dies.
• There is also a reverse protective technique: sprinkling of wood, rafting along the rivers. High humidity in 100% it is also capable of killing mold fungi.
• Flooding of wood helps to eliminate the development of mold. In this case, the spores also have no access to air, without which they do not develop.

For emergency drying of wood on which mold has begun to form, special heating devices are used: industrial heaters, specialized heat guns.

If a shallow surface lesion is detected, the area is polished until the blue is completely eliminated, after which a neutralizing composition is applied to it. If the lesion is deep, then the grinding step can be skipped.

As for the compositions, it is necessary to choose neutral liquids. Alkaline solutions have a bad effect on the composition of wood, they can cause the destruction of fibers.

To prevent re-infection, protective compounds. They are produced specifically to protect wood from mold fungi. A quality septic treatment is also suitable for protecting wood from blue stain.

The surface of the lumber is also covered with mastic. If there were no specialized compounds at hand, then clay, bitumen, paint can be used for these purposes.

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