Sealants for wood: varieties and applications

A building made from any raw material will need maintenance, care and repair over time. This is especially true for natural building materials, which include wood. Today, there are a huge number of different products for wood on sale, it should include a sealant for wooden bases..


Regardless of the type of wood, over time and under the influence of external factors, cracks or gaps can form on a wooden structure, since this natural material is prone to drying out to one degree or another. Modern advanced technologies are not able to stop this process, however, there are effective means that will help to eliminate the resulting defects, while maintaining the visual appeal of the tree and the reliability of the structure or structure..

Wood is a unique raw material for construction, the features of which are described below:

  • natural origin;
  • unique organic composition and fibrous structure;
  • hygroscopicity;
  • on most of the material, deformations arising from temperature effects are noticeable, in addition, the wood shrinks.

    The above features make the process of constructing buildings from a bar rather laborious.. It is not possible to fasten the constituent structures by welding, as is the case with metal, in addition, too rigid fixation of the elements is fraught with problems, since for structures made of wood it is necessary to compensate for the temperature expansion of raw materials. Such features also preclude the use of glue. However, the gaps between logs or timber cannot be left without appropriate processing, in particular, this issue is relevant when building walls of a house, arranging a floor, including parquet, installing windows and door blocks.

    Previously, sealing and insulation of cracks and gaps was carried out using tow, putty or jute fiber, however, working with such materials had some disadvantages, as a result of which materials appeared in the range of construction products that at times better cope with sealing. These products include wood sealants, which are commonly used for both exterior and interior work..

    The sealant can reliably fill cracks of any size, and after a minimum period, polymerize, forming a waterproof and elastic mass. The range of products includes materials in various shades, which allows you to ideally match the color of the composition to the tone of the log frame, due to which there will be no need to paint the base. In addition, it is worth noting that colored and colorless compositions can be tinted independently..

    The formed protective layer is resistant to ultraviolet light and temperature fluctuations, but the main advantage of the material, which makes it indispensable for wood finishing, is the ability to expand with the material. As practice shows, sealants have a level of elongation that exceeds the original dimensions by 300-400%..

    It is these specific properties of the products that provide the sealant with justified popularity, making it the undisputed leader among products for the repair and treatment of wood structures for any purpose..

    The products have the following characteristics:

    • film formation occurs 20 minutes after application;
    • polymerization of the substance occurs at 3 mm per hour;
    • the density level of the substance is 1.7 g / cm3;
    • products can operate in a temperature range that varies from + 75C to -30C.

    It is worth highlighting the reasons why the use of wood sealant is necessary:

    • the composition prevents damage to the material;
    • specialized substances effectively close the inter-crown suture;
    • product service life is about 20 years;
    • there are no restrictions regarding the climatic zone of application of the composition.

      In order to properly apply the product, it is necessary to take into account a number of general recommendations for work..

      • All work areas must be free of dirt and old materials used for processing.
      • Work on the street should be preceded by cleaning wood from snow and icing.
      • To maximize the adhesion of the joint compound to the substrate, it is necessary to prime the angles, seams and cracks..
      • For large-sized defects on wood, before treating the gap with a sealant, it is necessary to lay inside a polyethylene foam bundle, thanks to which you can save on the consumption of the composition.
      • The quality of sealing joints will significantly increase if in the course of work you use special guns or pumps. The choice of this or that working tool depends on the volume of planned work..
      • In the course of processing outside buildings, it is necessary to adhere to the temperature regime. Experts recommend to carry out the sealing of joints at a temperature not lower than 0С.
      • The sealant should adhere as tightly as possible to the wood.
      • Wet weather can increase the drying time of the formulation..


      Based on the specifics of the material, the main areas of application of wood sealant can be identified:

      • sealing of inter-log seams, gaps between the timber in the log cabins of houses or baths;
      • repair of cracks in the material – this can be wall cladding, flooring, log or timber from which the structure was erected;
      • using the composition, you can seal and insulate the joints and abutments of wooden structural elements to bases made of other raw materials, for example, stone, metal or concrete;
      • the composition is used to insulate and insulate door blocks and window frames, for these purposes there are compositions “Warm seam”;
      • the sealant is recommended for works on the arrangement and repair of the roof;
      • the composition has proven itself well during the treatment of internal substrates in humid rooms such as a bath or sauna.


      On the shelves of building supermarkets, there is a large selection of sealing materials for wood. They are classified based on many distinctive factors. Taking into account the composition, they can be divided into two types – two-component and one-component products. The last group of compositions is the most in demand. Given the scope of the sealant, the products are divided into household compounds and professional materials. They differ in the availability of components based on cost, as well as in the conditions of use and operation..

      Specialized teams are many times higher and require certain qualifications to work. Household sealants stand out for their ease of application. Information about which group of goods this or that sealing material belongs to is indicated by the manufacturers on the packaging. And also products for wood can be divided into two groups: compositions for outdoor and indoor use.

      All sealing materials consist of fillers, polymer composition, hardeners and additional substances that improve certain properties of the finished product.

      Considering the composition of the sealants, they are divided into the following product categories, presented below:

      • silicone materials;
      • acrylic;
      • polyurethane;
      • bituminous.
      • thiokol.

      The first type of substance includes two subspecies – neutral and acidic materials.. Acid sealants contain acetic acid, so the substance will have a corresponding odor during the polymerization process. Such products are considered universal, stand out at an affordable price, due to which they are in demand for construction work. However, the composition has certain drawbacks – acidic wood sealants cannot be used in conjunction with non-ferrous metal, marble and materials that contain alkali..

      Ketoxime or alcohol acts as a base for neutral products, due to which they can be used with all types of building materials. The products are much more expensive than the acid composition. Silicone sealants, according to reviews, are durable, perform well during external processing, and have water repellency. The material is resistant to temperature fluctuations, has good elasticity and resistance to external factors.

      Dirt does not accumulate on a completely cured layer, in addition, it is impossible to paint it or apply another layer of the same substance. Therefore, it is not possible to carry out spot repairs, in which case it is necessary to remove the entire composition and reapply it..

      Acrylic sealants are used most often, such materials stand out for their low cost and good adhesion to a porous surface. Products can be dyed, there are no toxic components and solvents in its composition.

      However, the indicators of elasticity and resistance to moisture are lower in comparison with silicone products.. Sharp temperature fluctuations negatively affect the material – it can begin to move away from the surface. Due to what acrylic compounds are advised to be used for interior work with wood in rooms with a low level of humidity.

      For external application, a special silicone-based acrylic-based material is commercially available. Such products have combined all the best properties of two sealants, which allows it to process the joint gap in log cabins, joints in openings, and also use it to repair other problem areas, including working with cork bases..

      Polyurethane-based sealants are the most expensive product in this line of building materials.. The compositions have excellent adhesion to most surfaces, in addition, they perfectly tolerate mechanical stress and have the highest elasticity among analogues..

      In addition, the products do not shrink after hardening, which greatly facilitates the calculation of the required amount of material for sealing joints and cracks. The compositions can be used for all types of work, in addition, they lend themselves to coloring after polymerization. Polyurethane sealants also have disadvantages, among which there is a meager color range and a low level of product resistance to sunlight..

      The materials are resistant to contact with some acids and alkalis and have a good degree of reliability, even when applied to a damp wood surface.

        Bituminous compositions are produced on the basis of rubber and bitumen, due to which they have the highest indicators of resistance to water. The main field of application of the products is the sealing and repair of roofs, drainage systems..

        Sealants for wood of the thiokol group are distinguished by their durability, in addition, the material is resistant to contact with solvents, acids, gasoline and other aggressive substances. Quite often, similar products are used at gas stations, service stations, and so on..


        After the choice of a suitable sealing compound has been made, you should decide on the choice of the manufacturer of the product, since the quality and reliability of the composition will largely depend on this factor. Among the brands presented on the market, there are several companies involved in the production and sale of these products..

        • Neomid – belongs to the group of acrylic products, with its help you can repair the timber, close up the end cuts on the logs from the outside and inside. The products have a high rate of elasticity and resistance to temperature fluctuations..
        • Remmers – German products are compatible with most paints and varnishes, belong to the category of universal compositions. Among the available assortment, materials are presented in a wide range of colors – you can purchase a white sealant, a teak or walnut color composition.

        • Ceresit brand – offers silicone compounds for wood, products are distinguished by resistance to ultraviolet and moisture.
        • Perma-Chink – recommended for work with cracks of great depth, it is allowed for use inside and outside the house. The application of the composition should be carried out at a temperature from +5 C to +32 C. For complete hardening, the material needs from 2 to 8 weeks.

        • Energy-Seal – water-soluble compound, which is recommended for sealing small gaps. Differs in color fastness, strength and vapor permeability.
        • Zobel – a German company specializing in the manufacture of paints and varnishes. In the range of offered sealing compounds, it is worth highlighting a butyl rubber product, silicone-based compounds, which have a high coefficient of elongation..

        In addition, the market contains compositions of the brands Oliva (“Oliva”), “Abris”, Axton, VGT.

        How to choose?

        In order not to be mistaken with the choice of the composition for wood, not to get confused in the proposed variety of modern products, some nuances should be taken into account.

        • Chopped new log cabins need a sealing agent that has the highest level of elasticity. This is due to the features of the structures, because it is in them that the level of deformation is more significant.
        • In a glued timber structure, conventional compositions can be used, since in this case the shrinkage rate will be small.
        • Before buying, it is imperative to check the expiration date of the product..
        • If the sealant is purchased in buckets, it is worth checking the tightness of the container lid..


        To calculate the amount of material necessary, you should determine the scale of work – measure the depth and width of the gap or crack. The flow rate can be calculated by multiplying the width of the work area by its depth. For triangular joints, the consumption must be divided by two.

        In addition, the instructions for the product always include information regarding the consumption of material per linear meter..

        The values ​​obtained can vary based on the density level of a particular composition.. Some manufacturers suggest using online calculators to calculate the amount of material..

        Application Tips

        To work with wood, the following tools will be needed: a gun, a narrow trowel with rounded edges, a paint brush, water and rags. When sealing seams and cracks with your own hands, the application of the composition is performed primarily on the horizontal gaps between the crowns, the joints of the material in the corners are processed last.

        The technology of work includes several stages.

        • Removal of dirt over the entire seam area with a damp cloth.
        • After filling the tube with the material into the gun, it is necessary to cut off the nozzle in it. For ease of use, the hole should not be more than 5 mm.
        • To distribute the sealant evenly, the gun must be held parallel to the gap. While extruding the substance, move the tool along the entire seam. The optimum applied layer thickness is considered to be 4 mm..
        • After finishing the application of the material with a spatula, the sealant is evenly smoothed out. It is not worth making great efforts, as this will negatively affect the thickness of the layer, as a result, it may become heterogeneous and cracked..
        • To remove excess material from the surface, it must be collected with a clean rag until it hardens. If a film forms, it should be moistened using a thin brush..
        • The technology described above is used to work with the rest of the surfaces..

        During the first three days, the composition should not come into contact with moisture. The material will acquire the final color after complete solidification..

          To seal the crack, it may be necessary to grind it, obligatory cleaning of debris, in addition, the gap must be blown. Further, along the entire perimeter, it is pasted over with masking tape, such a precaution will provide an even edge and a neat appearance to the layer. A sealant is inserted inside the crack, after which the sealant is applied in an even strip along the entire length. Excess can be removed with a spatula.

          Sealing products can be applied to the surface even in frost, however, it is not recommended to carry out work during precipitation. It should be borne in mind that negative temperatures increase the viscosity of the composition, which can complicate the process of applying products. Before working with wood, the sealant should be kept for about a day in a warm room. It is not recommended to dilute the products with water, as well as to mix materials from different manufacturers, as this will negatively affect the quality of the product and the sealing process. If the composition is frozen for any reason, you should not worry about its quality, you only need to defrost it at a positive temperature, but do not overheat and do not leave it near heating devices, as this can be fraught with damage to the product.

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