Choosing wood varnish for external and internal use

Wood surfaces, whether inside or outside, require wood varnish as a final touch. The durability and appearance of your wood can be greatly improved by selecting the appropriate varnish, which will protect it from damage and bring out its inherent beauty. But with so many choices, it can be difficult to determine which varnish is ideal for your particular requirements.

The challenging environmental conditions that the wood will encounter must be taken into account when choosing a varnish for external use. External varnishes are designed to endure changes in temperature, rain, and sunlight. These varnishes frequently have water-resistant qualities and UV blockers to stop the wood from fading, cracking, or decaying over time. Spar and marine varnishes are popular options for outdoor use because they provide excellent protection and longevity.

When it comes to interior woodwork, the emphasis switches to the wood’s intended use and visual appeal. Interior varnishes are available in a range of finishes, from glossy to matte, so you can customize the appearance of your flooring or furniture to your liking. In addition, they typically exhibit greater flexibility and reduced brittleness, allowing for the varying rates of expansion and contraction of interior wood. Because of their robust protective properties and ease of application, polyurethane and acrylic varnishes are popular choices for interior applications.

Selecting a varnish will be easier if you are aware of the particular needs of your wood surfaces, whether they are outside or indoors. You can make sure that your wood stays gorgeous and well-protected for many years to come by choosing the appropriate product.

What is the difference between the compositions

Varnish can be applied inside or outside of the rooms, contingent on the wooden base’s operating conditions. There are compositions that dry quickly, smell good, are water-based, oil-based, frost-resistant, and heat-resistant (fireproof).

There are varnishes that have a release form.

  • in spray cans (aerosol, sprays), which are convenient to cover small areas;
  • in containers (jars, bottles) applied by a brush, roller, spray gun.
  • Paul varnishes (parquet);
  • for decorating and emphasizing the structure of the tree;
  • For water transport.

The colors of varnishes

There are four types of coatings: semi-glossy, glossy (with brilliance), matte, and semi-dummy. High-gloss compositions are available for a powerful sheen.

  • The most popular in the market are transparent colorless varnishes that emphasize the natural structure of the tree.
  • It is possible to give beige, brown, red, black in a walnut shade of wood.
  • White varnish and the color "MEAGON" makes the tree visually voluminous.
  • Tinting varnishes for wood, obscure the surface, hiding its deficiencies. Used for wooden furniture and doors (in t. h. interior), parquet boards.

Types of varnishes in composition

  • characteristics of the mixture (drying period, coating thickness, presence or absence of smell);
  • conditions of application (for external or internal work).

The paint job’s cost is determined by the brand and manufacturer.

Oil varnishes for wood

  • The basis is oil and resin.
  • Dry in 1-3 days.
  • Deeply penetrate the breed.
  • Only for internal work.
  • Process furniture or other wood items.
  • For flooring is not suitable.

The amount of oil content dictates how long it takes for the applied layer to fully solidify.

  • skinny (oil content from 35 to 55%);
  • average (from 55 to 65%);
  • fat (from 65 to 85%).

Greater oil content in the composition leads to quicker drying times, but also increases wear exposure.

The mixture is initially too thick, so the product is diluted to a comfortable consistency before applying the brush.

The product is now less expensive because synthetic resins and oils are used in production. The composition contained natural oils earlier.


The ideal replacement for oil. The combination of natural (amber) and synthetic (thermoplastic, thermoreactive) resins forms the foundation of the composition.

Alkyd varnishes

The process is based on alkyd resins and involves the addition of solvents (white spirit or solvent) and sequestrants to speed up the drying process. Alkyd mixes can withstand changes in temperature and moisture. are affordable and have a high degree of penetration within the breed.

For a period of two to three years, the applied layer remains on the surface. Two days is the deadline for finishing the polymerization process.

Ideal for floating flooring, wooden floors, heated furniture, and t. h. The solvent in the compositions makes them toxic.

Working with protective gear (gloves, respirator) is advised.

They are separated into glyftal (GF) and pentifal (PF). Popular models from the previous category are the GF-166 and GF-177. Both representatives harden after 48 hours (GF-177 faster), and they both have a transparent glossy shine.


The use of polythera (alcohol varnishes) is limited. The amount of ethyl alcohol that dissolves the resin determines the composition. This wood varnish dries quickly. Drings in 20 to 30 minutes or less, depending on how quickly the alcohol evaporates after the layer is applied.

Alcohol mixes have a glossy appearance. used as a covering for glass, skin, furniture, and musical instruments.


Carbamide, pentapntal or glyftal resins. consist of two components and are only polymerized after an acid-based hardener is added. intended for use internally.

Give the surface a brilliant sheen; the coating is extremely resilient to moisture.

Applied to any kind of wood floor, including parquet boards. Indoor furniture is covered by them.


This translucent mixture solidifies when a hardener is added to the epoxy resin.

Because epoxy wood varnish can withstand heavy loads, massive floors, parquet flooring, interior doors, and other wooden products can be treated with it.

Its composition resists moisture and is suitable for both indoor and outdoor applications. takes a half day to dry.


These are multicomponent methods that rely on polyester resin inclusion. applied with a specialized gun, making it an unsuitable choice for novices. Following full drying, a transparent layer with a substantial thickness forms, offering excellent strength and resistance to moisture. withstands exposure to chemicals and high temperatures.

Typically, wooden musical instruments undergo processing.

Nitro -cellulose

Nitro-cellulose (also known as etherocellulose) varnishes are enhanced by the addition of resins, plasticizers, cellulose nitrate, and organic diluents.

The mixture does not tolerate atmospheric phenomena and has a low mechanical strength despite having a high resistance to moisture. The film may peel off the surface with time. effectively lends itself to polishing and dries quickly (20 to 50 minutes).

There are two types of coatings: matte (NC-243) and glossy (NC-218).

Toxic are nitrolaki, to. There is a solvent in the mixture. Only use a respirator when varnishing a tree, and make sure the space is well ventilated.

The applied layer is safe once the solvent has evaporated.

Because of its poor strength, it is not used for floors. They frequently cover tools for muses, wooden furniture, and pencils. Since varnish is not very tolerant of direct sunlight, it is best not to use it outside.


This water-soluble varnish has a strong adhesive bond and is odorless. The film is moisture-resistant once it dries, so you can cover a tree in saunas, baths, and restrooms. The coating is safe, dependable, and long-lasting without affecting people. It must be stored at a temperature below zero but not below five degrees Celsius and operated at a temperature of no less than twelve degrees Celsius.


Used as varnishes for yachts.

The mixture of harmful compounds (xylol and toluene) that have an impact on humans when they evaporate.

This varnish is the best for outside wood because it is waterproof, frost-resistant, and has an unpleasant smell. The coating is stable for approximately five years.

It is not advised to use it inside. Substances can continue to evaporate even after they have dried.


Varnish comes in one, two, and three component varieties. Prior to use, two components are prepared by mixing with a hardener. There is a solvent in the composition of three components.

Regarding the coating’s strength, this is one of the best materials. However, it dries for a very long time—two to three weeks—and smells really strong.

Following drying, the layer provides anti-corrosion protection and is resistant to high mechanical loads, moisture, atmospheric phenomena, and chemical substances.

Both internal and external applications. Polyurethane varnishes are widely used to preserve walls, parquet floors, yachts, and garden structures.

Acrylic varnishes

Because water-based acrylic varnish doesn’t contain any igniting materials, it effectively protects against fire. These are odorless, human-safe mixtures that can be used to open kids’ rooms.

Possess a high wood adhesion and vapor permeability, but their strength isn’t the best. Only the warmed surface should be coated with water varnish, which takes up to 15 days to dry.

Indoor applications are also feasible on concrete and brick bases.


Bituminous varnish is applied to wood to make it resistant to acid-base media and moisture.

The default is tinted brown. The surface after processing looks good.

It is applied thinly, and tiny areas can be dipped in to cover them.

Tinting mixtures

Wooden doors, furniture, and parquet flooring can all be painted. serves both a decorative and protective purpose. enhances the base’s strength, visually masks the wood to make it appear more expensive, and provides mold and fungus protection.

Food varnishes

Used on wood dishes that come into contact with food. There are no repercussions; the varnish is secure. It is acceptable to use toys for kids.

It’s important to take durability, finish, and environmental impact into account when selecting wood varnish for both interior and external applications. Choose a varnish for outdoor projects that can withstand the weather and provides strong UV protection. Indoor varnishes ought to emphasize bringing out the inherent beauty of the wood while offering a glossy, long-lasting coat. You can make sure your wood projects look great and last longer, whether they’re used to add elegance to the interior of your home or are exposed to harsh weather, by being aware of these important differences.

What to consider when choosing

The mixture is chosen with consideration for the circumstances surrounding its use.

  • Place of work. The rooms are selected inside the rooms without toxic components that are not smell during drying. For external work, varnishes for wood are suitable only with high characteristics of resistance to atmospheric phenomena (precipitation, sunlight, frost). On the street it is permissible to use materials with an unpleasant odor.
  • Wear resistance. Paul from wood, stairs must be covered with varnishes with high indicators of strength and wear resistance. For furniture, you can choose less durable materials, for example, nitro -cellulose.
  • Toxicity. For internal operation, it is better to choose water -based mixtures. They are not smell, safe, used without personal protective equipment. You can choose with the content of toxic substances, but do not forget about the respirator and protective clothes.
  • Drying deadline. If the repair must be made quickly, then the products on a water or oil base may not be suitable. They dry up to two weeks. While alcohol and NC, the compositions dry in 1-2 days.
  • Shine. Dullness or gloss does not affect the characteristics and quality of varnish. The choice depends on the preferences of the person.
  • Curing ways. Mixtures are divided into one -component, which are already ready to apply. And two -component, drying out of which begins after entering into the reaction with the hardener. It is better not to take two -component varnishes for beginners, since they need to work promptly and be able to withstand the proportions of kneading the components.
  • The need for primer. The priming of a tree increases the coupling with future paintwork. Without preliminary priming, a dried layer can exfoliate ahead of time. On sale there are varnishes with an already primer.


The most well-known producers:

  • Borma Wachs (Italy);
  • BASF (Germany);
  • Tikkurila (Finland);
  • Bona (Sweden) and their Traffic product based on polyurethane;
  • Sayerlack (Italy);
  • Berger (Germany)-polyurethane Aqua-Eal;
  • Akzonobel (Holland);
  • Vermeister (Italy) – Aqua Play 2k water -based polyurethane remedy;
  • Henkel (Germany).
Criteria Description
Exterior Use Needs to be weather-resistant and UV-protective to withstand sun, rain, and temperature changes.
Interior Use Focuses on durability and aesthetic finish, with less need for weather protection.
Water-based Varnish Low odor, quick drying, and easy to clean up with water; suitable for indoor projects.
Oil-based Varnish Provides a rich finish and high durability; ideal for outdoor use due to its robust protection.
Matte Finish Offers a non-reflective surface, good for hiding imperfections; commonly used indoors.
Gloss Finish Provides a shiny, reflective surface that highlights wood grain; suitable for both indoor and outdoor use.
Application Method Brush, roller, or spray can be used; choose based on project size and desired finish quality.
Drying Time Varies between products; faster drying is usually better for indoor use, while outdoor projects can accommodate longer drying times.
Environmental Impact Water-based varnishes are typically more environmentally friendly; consider low-VOC options for indoor air quality.

It’s crucial to take into account the unique requirements of both interior and external applications when choosing a wood varnish. Look for varnishes that provide strong weather protection when using them outside. In addition to water resistance to guard against moisture and mildew, these products should have UV resistance to stop fading and cracking. It takes a strong, long-lasting finish to preserve the integrity and beauty of external wood surfaces.

For woodworking indoors, the emphasis can be slightly changed. There is more flexibility in terms of finish and appearance, but durability is still crucial. A varnish with a rich, warm tone that draws attention to the wood’s inherent beauty might be your top choice. Indoor varnishes are available in a range of sheens, from high gloss to matte, so you can customize the look you want for your room. Furthermore, reapplication can usually be done less frequently in indoor environments, which facilitates easier maintenance.

Take into account the application’s simplicity and drying time as well. Certain varnishes can save a lot of time by drying quickly and allowing for multiple coats to be applied in a single day. Others might offer better protection and finish, but they might take longer to cure. For optimal results, always adhere to the manufacturer’s instructions.

In the end, selecting the ideal wood varnish requires striking a balance between practical requirements and aesthetic preferences. Whether you’re finishing a dining table for daily use or shielding a deck from the sun and rain, choosing the right varnish will guarantee that your wood surfaces look great and last for many years.

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Daria Yakovlev

Interior designer, author of online color design courses. I will help you create a harmonious interior using color.

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