Home Article How to coat OSB outdoors

How to coat OSB outdoors

Step by step instruction

Experts have different opinions about the technology of painting OSB facades. If you don’t like the texture of the chips, sand the boards with an angle grinder with a P320 abrasive wheel. In other cases, the material may not be leveled.

Priming is the first step in the staining process. If you do not use a compound designed specifically for OSB sheets, quality adhesion will be difficult to achieve. Since OSB-3 without special protection against moisture is usually used for exterior work, it requires additional processing.

To prevent OSB boards for facade finishing from starting to warp and swell during operation, prime the ends before installation. The ends are the most vulnerable place of the material. The primer will maximize protection of the material and increase its service life.

If you want to achieve a perfectly flat surface, the base should be completely covered with fiberglass mesh and leveled with waterproof and cold-resistant putty. When using hiding latex paint you can skip the leveling step: experts say that the painted surface is smooth and does not require priming.

After the materials have dried, paint the board with a facade paint in two or three coats. The first one should be as thin as possible. Paint facades in dry weather, in the sun and in temperatures from 5 ° C.

The paint can be applied with a brush or paint roller: both foam and synthetic fur can be used. But the lowest paint flow rate and the fastest painting speed will be with the spray gun.

The first layer of paint is left to dry for a few hours: the exact amount of time depends on the type of compound. Be sure to read the instructions before applying the paint. It is preferable to dry outdoors without prevailing winds or sudden temperature fluctuations. To achieve a uniform coating, the compound should be applied in an even layer without any gaps or overlaps.

Tip: To make the facade look stylish and neat, close the seams with a decorative layout of boards 25×100 mm. Their location is dictated by the size of the boards, so before cladding you should calculate not only the amount of material, but also the placement of the sheets. The dark boards with joints that cover the seams against the light paint finish to imitate a half-timbered beam.

OSB is a board material made from wood chips. However, unlike the familiar and familiar particleboard, a different technology of creation is used here. The strands are not simply mixed with glue and pressed, but are placed in layers and the strands are oriented differently in different layers. That’s where the name. “Oriented. chipboard” originated. By the way, the name “OSB” will be incorrect, as the abbreviation should sound like “OSB”. Nevertheless, even in stores sometimes you can see the wrong name for this material.

The strength of the parts is not in doubt. they are used to build the supporting structures of houses. However, there are several varieties of such boards that differ in their characteristics:

  • The first type is OSB-1. Not too strong and not resistant to water details.
  • The second variety. OSB-2. more resistant to water and much more durable boards.
  • Type three. OSB-3. parts suitable for interior decoration, as they have sufficient strength and can withstand the effects of moisture quite well.
  • OSB-4. structural parts used in the construction of various buildings.

Floors are usually assembled from the third type, since they fit all the characteristics. In this case, it is important to choose materials produced in Europe, in which the binder is a resin that does not release formaldehyde into the air. Domestic products, as well as parts of China, are made using resins that contain a lot of formaldehyde and can not be used for internal structures in the house.

OSB. OSB is not the same

It is necessary to say at once that not any OSB is suitable for cladding a house outside. OSB or OSB boards are sold in two conditional types.

If you opt for the classical boards, in which the surface is seen in the relief of wood chips and wood shavings, then for the facade cladding fit only OSB-3 or OSB-4. OSB-1 and OSB-2 are used only for interior finishing.

coat, outdoors

In addition to classic OSB boards, you can also buy sheets with laminated or varnished coating, which significantly increases the service life of the material in conditions of outdoor wet traces. There are also tongue and groove OSB boards, which are treated with water-resistant compounds.

House facade made of OSB sheets (also called OSB and OSB boards).

For more information on the properties of different types of boards, see this article: What are OSB boards, their types, characteristics, use.

What to impregnate outside?

The use of OSB as outer cladding of buildings is quite widespread in Russia and abroad. According to standards only boards of OSB-3, OSB-4 qualities are suitable for these purposes. They can be used outside the house due to increased protection from moisture, from atmospheric precipitation. But even in this case, the material in prolonged contact with water can swell, no longer returning its previous geometric parameters.

Protect the material during storage by insulating it from the effects of atmospheric factors. For this purpose they use shelters, polyethylene film. After installation on the facade of the panel, even with high rates of moisture resistance should be further covered with a protective composition.

The choice of means to be treated ends and parts of the material on the facade of the building is largely individual. Not all compositions for outdoor use meet the requirements of safety and environmental friendliness.

The decision to impregnate the panels on the facade is most often associated with the rejection of other types of decorative finishes. In general, this style is quite in demand in cottage and suburban construction. But without protection material after 2-3 years will begin to lose its original color, at the joints will appear mold and fungus. About what compositions are suitable for facade use as a coating for OSB-plate, it is worth talking in detail.

Colorless impregnation

They are designed for solid wood, but can be used for any material based on it. OSB falls well into this category. Cannot be used for slabs only with water-based impregnators. Among interesting products on the market there are several variants.

  • Neogard-Tree-40″ hydrophobizer. It has an innovative formula based on organosilicon compounds that can reduce water absorption in wood-based materials by up to 25 times. The composition is completely transparent, re-treatment is required after 5 years.

How to make OSB sheathing last longer for barns dog house new addition walls

  • Elcon antiseptic impregnation. Universal silicone-based product. It is suitable for indoor and outdoor work, does not leave a pungent smell, and is environmentally friendly. The coating has hydrophobic properties, creates a film on the surface of the boards, which prevents the reproduction of microorganisms.

Colorless impregnations are suitable for OSB pretreatment before installing other types of decorative finishes. In addition, they allow preserving material structure, if necessary, without excessive glossiness.

Alkyd, water-based and oil-based varnishes

Varnishes. transparent and matte, tinted or classic. are the easiest solution to protect OSB from external influences. They are on sale in a wide range, you can find an option for any budget. One thing to remember: varnishes can be damaged quite easily, making the material vulnerable to swelling, mould and mildew.

The most popular paintwork materials have alkyd-urethane composition, they are also called yacht. Such products are produced by many well-known brands: Tikkurila, Marshall, Parade, Belinka. varnishes of this type are ecological, they create on the surface of the material a moisture-proof film of increased strength. True, the cost of urethane-alkyd compositions is also not too cheap.

Varnishes on a water basis. acrylic. are most often supplemented by antiseptic components, may contain wax, which increases the resistance of the coating to moisture. They are durable, easy to apply, but do not withstand considerable drops in temperature too well. Oil varnishes have olive in their composition, the color of the coating varies from straw to burnt sugar. The coating retains transparency, reflects light well and has a presentable appearance.

Oil varnishes tolerate temperature differences well, are easy to apply, and are thick enough to avoid excessive flow when applied.

Oil and wax impregnations

Not only classic paintwork compositions, but also oil and wax mixtures are produced on an oil base. OSB may well be supplemented with such coatings. Tinting on the basis of natural components. linseed oil and beeswax. does not cause emission of dangerous chemicals. The finished coating has a nice honey color, becomes resistant to moisture. It is difficult to compare it with classical lacquering, but the result is quite similar.


Tinting impregnations are well known to all lovers of self-treatment of wood. They are used as a means to emphasize the original texture of the material, help to give it the right shade. The stain in its classic variant dissolves with acetone, and when painting the surface dries in 5-10 minutes. Applying the composition on wood boards combined with the formation of external moisture-resistant coating of polyurethane primer.

Using the stain in combination with other additives it is possible to visually age the surface, patinate it. Many compositions have additional capabilities to the biological protection of the material, to prevent the defeat of constructions by insects, fungus and mold.

Coating compositions

This category of varnish-and-paint products has an important property. the ability to mask the characteristic relief of OSB-panel. The compositions have a dense structure, are well covered even in 1-2 layers. The hiding power increases with the use of primer.

Consider the most popular formulations in this category.

  • Acrylic paints. Despite the water base, they also contain polymeric binders, adhere well and tightly, do not spill on the surface of OSB-sheets. Acrylic paints are considered to be among the most environmentally friendly, they are air permeable, have no pungent chemical odor. Such coating easily withstands all atmospheric factors, can be used at winter temperatures down to.20 degrees.
  • Latex paints. Water-resistant materials, suitable for finishing exterior walls of the house from OSB boards. The latex paints have good covering power, they are suitable for application on new constructions, as well as on the already used wood and chipboard constructions. They are well tolerant to the changing weather factors, frost resistant, easy to tint in the desired shade.
  • PF. Pentaphthalic based paints are highly viscous, covering closely and are very opaque. They perfectly adhere to the surface of wooden boards, forming on it a strong moisture-proof film. For external works the paint, marked PF is suitable only for use on porches under the roofs, when cladding the porch. The compositions are long drying time, may burn out in the sun.
  • Alkyd enamels. One of the best coating options for OSB facades. Paints of this type lay down well, providing the creation of a dense decorative coating, retain brightness of color for a long time. Alkyd compounds are weatherproof and durable, but are not suitable for interior work because of specific chemical odor.
  • Silicone paints. One of the most expensive types of coatings. They are applied on top of whitewash or primer and can be sealed. After drying, the silicone coating gives the surface moisture resistance, increases its mechanical strength.

The main thing to consider when choosing a coating. it should not contain water (except acrylic paints). Optimal characteristics for outdoor use have alkyd enamels, latex and silicone means.

What to paint OSB boards outside and inside the house?

Many ways to finish an OSB house are quite expensive and require highly skilled builders or craftsmen. For example, vinyl siding for a hundred thousand you can ruin, if the banal too tighten the bolt heads fastening the siding and trim. Only now there are special paints and compositions for the finishing of OSB boards on the market. There are primers, there are expensive solutions of western producers, and there are paints for OSB having protective properties in addition to decorative function.

Finishing the house outside with OSB

OSB boards are used for the construction of frame buildings or so that wooden houses can be clad. They are not bad indicators of insulation and durability, although this material is not sufficiently moisture resistant. Raw materials for the manufacture of OSB is a non-working coniferous wood or wood processing waste. OSB facade can be deformed by water. Nevertheless, it stands out for its own environmental friendliness, practicality, easy to handle and install.

Building experts advise using OSB. 4 or OSB 3 for cladding the outside of the house, but the second option is considered less preferable. You can clad the outside of the house OSB of the third group, but it does not have any special protection against moisture, so it must be treated additionally. OSB 4 is noticeably more expensive, so the external finishing of the house with OSB boards in the construction of economical buildings is not very often.

As OSB is based on wood chips, exterior finish can be treated with any paint compositions suitable for wood-based materials. Limitations are determined solely by aesthetic features. In particular, you do not need to choose transparent varnishes, as well as glazes. The particle texture is not endowed with special beauty, so it is not necessary to expose it to the public.

In addition to painting OSB boards, facade plaster is also suitable. Technology of facade plastering is described in detail in the corresponding article, it will have no special features, if the basis of the wet facade is OSB board. You can plaster both with and without insulation. Pay attention to the primer, it increases the adhesion of the base, t.е. Stucco composition is better to lay and fasten. In this article, let’s talk in detail what to paint the wasp on the facade.

Read more about the characteristics and properties of OSB boards here.

What to paint OSB board outside and inside the house: 8 tips

OSB, as an affordable and reliable material for its performance characteristics, is widely used both for interior and exterior decoration, and for the construction of light frame structures. In view of this the question often arises. what is better to paint the OSB boards outside or inside the house? But why do you need to produce staining, and whether it is always topical?? You will find the answers to these questions in our article.

Oriented strand board (OSB) consists of up to 90% natural wood in the form of coarse chips. Crushed wood chips are connected with each other by bonding with different types of resins, polymers and adhesives. The result is a dense and hard material. But, as we know, natural wood is afraid of moisture and can swell under its influence. To protect the boards, they are impregnated with different chemical impregnations. It is from the type of impregnation used and depends on the labeling of boards. Surely you’ve noticed that the abbreviation OSB also has a number in the name. What it stands for?

  • OSB-1 has a minimum level of moisture impregnation in its composition, so it is suitable for use only in dry, heated rooms.
  • OSB-1 is capable of withstanding only a brief and minor impact of moisture;
  • OSB-2 is designed for finishing inside premises with average humidity level;
  • OSB-3 is capable of withstanding exposure to high levels of humidity, and even a short-term soaking;
  • OSB-4 is the most resistant category of material to moisture. Recommended for exterior use.

What peculiarities should be considered when choosing a paint for OSB

When choosing a paint coating for OSB one should take into account certain peculiarities of this material.

Adhesion of paint coatings and OSB boards

Some paints do not adhere to the surface of OSB very well because of poor adhesion between the materials. This is because OSB is initially impregnated with resins and does not absorb paints very well. To paint OSB it is not recommended to use water-based paints and other compositions on a water-soluble basis. Acrylic or other polymer-based coatings should be preferred.

The texture of the OSB board

The peculiarity of this material is its pronounced texture. The surface of the board is uneven, rough. this increases the consumption of paint and requires preconditioning before painting.

The age of the OSB board

The worst to be painted OSB boards that were not protected with coatings and have been outdoors for more than a year. Under the influence of ultraviolet radiation and humidity the quality of the OSB surface strongly deteriorates. Even paint specially designed for OSB boards does not adhere well to such surfaces. In this case for quality painting surface cleaning from dirt, sanding and antiseptic treatment is required.

OSB painting methods

To protect the material from unfavorable external factors and make the construction presentable, OSB is painted. However, the method is chosen based on the overall situation of the type of stove installed. Let’s look at what to paint OSB with, and we’ll discuss each case in detail.

Covering enamel

This material is used in the situation where you want to hide the uneven surface of the board. High density of enamel helps to hide all visible effects. Paints are water-based or oil-based. It takes very little material to paint, because it is slowly consumed.

The advantages of this method of painting include:

  • low consumption of material;
  • Elimination of defects and surface roughness;
  • bright color palette;
  • strength and durability.

The negatives include the long drying time of the material and the intolerance of ultraviolet rays. Thus, in the sun the paint will fade and gradually lose its appearance.

Transparent coating

When it is necessary to decide what to paint OSB on the street, the most universal way is to paint with transparent materials. They do not impart a different color to the panels, preserving their wood texture. But at the same time such paints protect the surface from unfavorable external factors.

The best is a paint based on alkyd resin. It prevents the fading of the material, as it contains special components in its composition, which can withstand the effects of the sun. Among the transparent materials for painting stand out:

coat, outdoors

The latter materials are the most reliable.

Weather Proofing OSB Flooring | Off Grid Cabin Build #30

Alkyd paint

The material is made by mixing several components of acids, oils, and resins at high temperature. Alkyd-based paints are well tolerant of sunlight and do not change color at low temperatures. Dries quickly, forming a protective film.

The disadvantages of the material include the following:

  • High flammability level. In the composition of the coating there are elements that are very susceptible to fire and ignite in the first place. To avoid this, it is necessary to cover the OSB boards from above with special emulsions.
  • Do not apply on a wet or poorly dried surface. Paint will not adhere to damp material, so it is better to choose sunny and dry weather for quality painting.

How to Seal Wood. Waterproof OSB Boards. Shed Exterior

If you need to choose what to paint OSB outside the house, then this method is perfect for this purpose.

Firebioprotective materials

For additional protection of the boards from fire and release of toxic substances use a special paint coating with a firebioprotective composition. In addition, it gives the material extra density. Applying this material on the OSB board contributes to the following positive factors:

  • protects the boards from fire;
  • Prevents the formation of mold and mildew;
  • Forms a special protective film;
  • helps to fight high humidity.

Firebioproofing can last a very long time if properly applied and maintained in good condition.


The most widespread variant of OSB painting. As part of this material is the stain, which must be diluted. This is done with acetone, water or a special solvent. It is applied easily to the surface and dries just as quickly. Requires mandatory coating with primer on top.

Acrylic paint

To understand what to paint OSB outside, it is necessary to compare all represented paints and coatings. The most common paint is acrylic. It is used to coat facades of houses and outdoor structures. Water and acrylic, which are part of the material, evaporate in time, and only a beautiful decorative layer remains.

Among the advantages of this method can be noted:

  • Protection of OSB against fire;
  • Prevention of exposure to moisture;
  • protection against fading and ultraviolet radiation;
  • great choice of colors.

The acrylic paint is also a very inexpensive material with an economical consumption.



| Denial of responsibility | Contacts |RSS