How to protect a wooden house from rot, mold, insects and fire
No matter what new materials a person invents, wood will not give up its place. Wood was and remains one of the most important types of building material, but in order for wooden structures to serve for a long time, they must be protected.
First, from lower spore-forming plants, commonly called fungi, which germinate in wood and form the well-known mold and rot that destroy wood.
Secondly, from insects that spend part of their life cycle inside wood and are called woodworm beetles. The larvae of the latter «eat out» winding passages inside the wood, because of which the whole product may simply crumble outwardly.And, finally, thirdly, wood should be protected from fire — wood belongs to combustible materials. Wooden houses suffer greatly from fire, and it is still not uncommon for people to die as a result of fires in entire villages.
Protection of a wooden house from rot, mold, insects and fire. For the safety of structures made of wood
House fungi that cause the appearance of mold develop where changes in humidity and temperature are observed. And if it is impossible to protect the wood from moisture, then it will definitely be covered with mold.
Woodworm beetles (sometimes called grinder beetles) infect wood with their eggs, laying them in poorly peeled wood and cracks in wooden objects. Larvae of these beetles, eating wood, make channels in it. Only when the larva becomes a pupa, and then turns into a beetle that must crawl out, only then will a hole appear on the surface of the wood. The size of the hole depends on the breed of beetles — the barbel chews through a hole with a diameter of more than 5 mm, the grinder is smaller, and the furniture grinder is generally about 1 mm.
The means used to protect wood from fungi and beetles are similar in properties and are called antiseptics. These products are subject to requirements of high toxicity in relation to wood-destroying fungi with their harmlessness to humans and animals. Antiseptics retain high toxicity for a long time, easily penetrate wood, do not degrade the mechanical properties of the latter and do not cause corrosion of metals, do not complicate the finishing of wood, etc.
The main method of using antiseptics is the impregnation of wood both in the finished product and in the form of blanks. According to the degree of impregnation, tree species differ greatly from each other. According to this property, they are divided into three groups:
easily nourished: sapwood of birch, beech and pine (sapwood is wood around a dark central core on a cut);
moderately nourished: cedar, alder, aspen, hornbeam sapwood, oak, maple, linden and European larch, pine core;
difficult to feed: spruce, Siberian larch, fir, central zone (core) of birch, beech, elm, oak, European larch and ash.
Different wood resists microorganisms in different ways. Therefore , according to the resistance against the development of fungi , tree species are divided into four classes:
I — resistant breeds: pine, ash, oak and larch core;
II — medium-hardy breeds: spruce, fir, peripheral part of cedar, larch sapwood, central zone of beech;
III — low-hardy breeds: sapwood of birch, beech, hornbeam, oak and maple, elm kernel;
IV — unstable rocks: alder, aspen, lime sapwood, central birch zone.
As you can see, rocks that are not resistant to infection are also difficult to impregnate. Thus, using the data provided, it is easy to assess the risk of infection of your building. If the building is made of coniferous wood, then it will stand without antiseptic impregnation, but if the house is cut down from logs of hardwood trees, whose resistance to microorganisms is clearly insufficient, additional processing of logs will be required.
Compositions for protecting a wooden house from fungi and insects
Some characteristics of antiseptic products are given in Table 1.
Table 1. Antiseptic products
drying time, h
|up to 1||water||0,1|
|up to 1||water||0,1|
|Sadolin Bio Clean*
|Dulux Kichens & Bathrooms
|up to 10||white spirit||0,1-0,2|
|up to 0.5||not required||0,2|
|up to 24||white spirit||0,1|
|up to 10||—||0,08|
|Sadolin Pinotex Classic
|up to 12||turpentine||0,1-0,2|
|Sadolin Pinotex Base
|up to 24||white spirit||0,1-0,2|
|up to 24||turpentine||0,08|
|Beckers Exponyl Traskydd
|Fintex KSM 42**
|Note: *) — contains sodium hypochlorite; **) — with biocidal additives.|
Among the domestic water-soluble preparations, the compositions «Ecolan» on an acrylic basis can be noted. So, «Ecolan-41» is intended for interior work, it belongs to the group of coating compositions (that is, it reveals and emphasizes the texture of wood), used for tinting surfaces in order to imitate valuable wood species. The composition dries quickly — from 20 minutes to 1 hour, the composition is applied in any way (brush, roller, spray) in two layers. The smooth surface to be treated is pre-cleaned of mold. Note that by closing the pores of the wood, the alkyd composition prevents further impregnation of the material with any other compounds. Suitable «Ecolan-41» and for application on external surfaces, if after covering them with a protective varnish.
«Ecolan-50» is designed for impregnation of both internal and external surfaces, as well as for waterproofing brick walls. Otherwise, «Ecolan-50» does not differ from «Ecolan-41», that is, it is used as a coating compound (by the way, it gives an attractive bright look to the brick wall, preventing the formation of salt plaque on it).
Protective and decorative coating «Olivesta-Olidekor» (Russia) is a water-dispersion compound for the protection of both internal and external wooden surfaces, and is also used to simulate valuable wood species.
Antiseptic concentrate «Emlak Antiplesen» allows you to treat surfaces of wood, concrete, brick already touched by mold and algae, killing microorganisms and preventing their reappearance. «Emlak» is diluted with water in a ratio of 1:2 before use. After 12 hours, dead microorganisms must be removed from the treated surface. It should be noted that «Emlak», like all water-based formulations, is quite easily washed out, so its protective effect in a humid atmosphere does not exceed one year.
The water-based preparation «Rogneda Biosept» (Russia) is a composition of a wide spectrum of action. It effectively protects wood from blue, mold and all types of woodworms (bugs, shashels, etc.), protects the stone surfaces of houses, basements and cellars from the appearance of fungi and mold on them, is added to finishing and masonry materials, as well as adhesives, continuing to act for 4...5 years. The drug is environmentally friendly — they are allowed to process even bags for storing agricultural products. The surfaces treated with this composition are easily painted with any paint. But a wall treated with any alkyd-based compound, «Rogneda» will not be able to be impregnated.
Hypochlorite solutions («bleach») are widely used among aqueous formulations to combat mold. It is to such compositions that the Finnish «Tikkurila Homeenopoisto» belong (breeding for application 1:4) and «Sadolin Bio Clean». Such substances should be handled carefully, since they are characterized by excessive activity (they can bleach wood and affect metals) and pose some danger to humans (they form poisonous gas and can cause skin burns). These products are also very unstable: after 15 after 20 minutes of being outdoors, they lose activity. But if after the hypochlorite composition«Tikkurila Homeenopoisto» the surface is additionally coated with an antiseptic, then the effectiveness of the composition will remain from 5 to 15 years.
The water composition «Caparol Capatox» (Germany) is intended for the destruction of mold on the inner and outer walls of stone, brick and similar buildings (mainly used for renovation of architectural monuments), as well as in bathrooms, bathrooms, etc. «Karuwa Schimmel-Ex» (Germany) is intended for the same purposes as the above composition. It should be added that in both cases, for more reliable protection of the walls, they need to be varnished or painted.
Water-based solution «Dulux Weathershield Fungicidal Wash» (Great Britain) is universal — suitable for the protection of both wooden and stone buildings, while having a high covering capacity. The peculiarity of the drug is sufficient effectiveness in wet conditions (wet wall), but this ability is not given for nothing — the composition is toxic and it is better not to use it indoors.
Alkyd-based protective compounds are produced not only in the «water version». Many preparations require hydrocarbon solvents instead of water, which are most often white spirit or turpentine.
So, texture coatings «Rogneda Sotex» and «Rogneda Aquatex» (Russia), used for decorative and protective treatment of exterior and interior walls made of wood, diluted with white spirit (or solvents 646 and 647). The compositions form an environmentally friendly (after complete drying!) coating (the term of preservation of protective properties is 5...6 years), imitating valuable wood species or differing in one color or another.
Colorless «Sotex» is added to oil and alkyd paints, but with direct exposure to ultraviolet radiation, the presence of the drug in the paints leads to accelerated fading of the latter.
«Aquatex», although it is bred with white spirit, it is allowed to be applied to a surface whose humidity reaches 35...40%. At the same time, it forms a water-repellent bioprotective breathable film resistant to ultraviolet light.
«Polyex Polytex» (Russia) on an alkyd basis contains bactericidal preparations of the company «Bayer», tinting compositions of the company «Tikkurila» and imported alkyd resins. Designed to protect against mold and rot. «Polyex Woodpecker» is used for preventive treatment of wood from insect infestation.
Tinting compound for decorative and protective treatment of wood «Odilak Lazurol» (Russia) on an alkyd basis, it was created using components from Slovenia, where a number of decorative and protective compositions for wood are produced, of which the composition «Belinka Lasur» is found on the Russian market for exterior and interior work, including for protecting the facades of wooden houses, roofs, fences, garages, floors and walls in conditions of high humidity.
Composition «Sadolin Pinotex Classic» (Finland) — pure antiseptic with organosilicon and color additives (30 shades) forms a protective weather-resistant transparent water-repellent film, preventing wood rotting, as well as the appearance of mold and blue on it. The colorless composition «Pinotex Base» (without pigments) protects the wood from rotting and mold, but does not provide a UV-resistant coating. The composition is often used as a primer. All compositions of «Pinotex» are toxic, it is better not to use them for interior treatment (or to cover them with a durable varnish).
The drug «Dyo Pinostar» (Turkey) is very similar in properties to «Pinotex».
Since bactericidal compositions are usually compatible with coloring, the appearance of paints with bactericidal properties has become quite natural. The combination of staining and biosecurity functions is manifested in many paint compositions: the paint «Dyo Dyoplus» (Turkey) based on PVA gives a stable waterproof and breathable film that does not burn out in the light (30 colors) and at the same time protects the surface from fungi.
Water-based paint «Dulux Kichens & Bathrooms» (UK) is much stronger and more durable than conventional water-dispersion paints. It is designed specifically for kitchens and bathrooms, protecting the walls from mold. Latex paint «Fintex KSM 42» (Finland) is also not for wood — it is intended for painting any other wall coverings, including even cullet. By the way, this paint can be used to paint surfaces after applying alkyd compounds to them. The film can withstand up to 30,000 treatments with a brush and detergents.
The same properties are possessed by acrylic paint «Diva-M» (Russia).
Compounds that protect wood from ignition
As already mentioned, in addition to fungi and insects, fire is a dangerous scourge for wood. So, wooden buildings are protected from fire by flame retardants (coatings, foaming compounds, impregnations). And if bactericidal substances are introduced into one or another impregnation, then it acquires fire-protective properties (see Table 2).
Table 2. Fire and bio-protective compounds (Russia)
|Brand||Drying time, h||Consumption, l/m²|
The protective effect of flame retardants is different. For example, some flame retardants emit inert vapors or gases that make it difficult for the gaseous decomposition products of the ignited material to ignite.
Among the fire-protective compounds in the first place should be mentioned the impregnating composition «Rogneda KSD» (Russia), containing both antiseptic and fire-fighting components. After impregnation, the flame—retardant properties of the composition remain for at least 2 years, and the bio-protective properties — up to 5 years. Such a long period of protection is provided by a thick synthetic film forming on the surface of the material treated with the composition. This film works as a semi-permeable membrane.
«Rogneda KSD» is used for processing (inside and outside) wooden buildings, as well as rafters and lumber. The advantages of the composition include: high penetrating ability and the possibility of applying the composition over any paint coatings.
The flame retardant «Claude-01» (Russia) is suitable only for internal use, that is, they are allowed to process the interiors of premises and wooden parts of internal structures. The film formed on the surface of the material when using the drug has water-repellent properties, so that «Claude-01» is successfully used in damp rooms. However, this film is unstable to ultraviolet radiation and frost-resistant.
«Firex-200» (Russia) is a flame-retardant foaming paste designed to create flame-retardant «walls». When exposed to flame, the flame retardants included in the preparation decompose with the release of an inert gas, and the film of paste applied to the surface of the material foams, increasing in thickness by 10...15 times. «Firex-200» protects treated surfaces from contact with fire for 45 minutes. Paste is widely used, mainly on railway transport, but it also finds application in domestic conditions.
The composition «Glims OgneStop-20» has long been used to protect monuments of wooden architecture. The composition itself is easily washed out, however, in combination with the composition «Glims LesSil» it is also successfully used as external protective coatings. «Glims LesSil» is a curing agent containing an antiseptic, an organosilicon water—repellent component and additives that reduce the ability of wood to absorb water. When treated with these compounds, the appearance of wood and its gas and vapor permeability do not change.
If the first two formulations («Rogneda» and «Glims») contain a sufficient amount of antiseptics, then «Claude-01» and «Firex-2000» protect the wood by creating only an insulating coating.
Antiseptic properties of the drugs are mainly given by water-soluble fluorides — sodium fluoride, sodium silicofluoride and ammonium. They do not stain the wood and do not reduce its strength, but they are easily washed out with water and therefore require additional protection.
Oil-soluble antiseptics are usually associated with creosote, which has long been impregnated with railway sleepers. Coal oil (creosote, anthracene, shale) is not washed out by water, but the wood impregnated with it (sleepers, supports, bridge elements, etc.) does not stick together, does not stain and acquires a characteristic dark color.
Mixtures of sodium bichromate and zinc chloride with copper sulfate (or without it) have long been used as bio- and flame retardants — but these compounds are very toxic.
Abroad, according to experts, the impregnation of wood with ordinary table salt is becoming increasingly widespread, which ensures environmental cleanliness, more or less reliable protection from beetles and the creation of an environment unsuitable for the development of fungi.
Methods of applying antiseptic and fire- and bio-protective compounds, as a rule, differ little from the process of applying protective coatings and are performed using the same tools and equipment. Since many compounds are toxic, and environmental cleanliness is acquired only after their complete polymerization, when working with them, follow the safety rules.
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