Types of primers for wood under varnish and the rating of the best brands, rules of application
Wood poorly tolerates external influences. Due to regular contact with moisture, the material molds and rots, which reduces the service life of structures. To avoid such consequences, specialized primers are used for wood to be painted with varnish. Such formulations prevent rot and mold formation, and also improve surface adhesion. That is, thanks to the primer, the service life of the paint increases.
Do I need to prime the wood under varnish?
It is believed that the varnish is able to protect the wood from the negative effects of the environment. However, this composition partially solves this problem.
Wood should be primed in cases where the material is in constant contact with water or is used in conditions of high humidity. Varnish in such situations is not able to prevent the development of mold or rot.
However, not only these problems are solved by the primer.
Purpose and properties of soil
The wood primer has several purposes:
- Surface disinfection. The tree is prone to rot. This process is accelerated in conditions of high humidity or against the background of the reproduction of pathogenic microflora such as a fungus. The primer, which has antiseptic properties, prevents the development of these processes, and also repels insects.
- Surface reinforcement. Wood has a porous structure, which weakens the material over time. The primer penetrates deep into the surface, holding the fibers together and thus increasing the life of the structure.
- Decreased absorptive capacity. Wood absorbs moisture well, and the soil prevents it.
- Increased adhesion. Thanks to the primer, the surface acquires a rough structure, which increases the level of adhesion of the applied paint. This allows you to reduce the consumption of finishing materials.
- To level the surface. The soil, as mentioned earlier, binds the fibers together. As a result, the paint applied to it forms an even layer after drying.
- Prevention of defect formation. Wood contains resins, tannins and other substances that leach out over time. This creates visible stains on the surface. The primer layer prevents substances from escaping.
It is necessary to prime the tree in the following cases:
- the material is used in the outdoor environment;
- wood is located in rooms with high humidity;
- defects were found on the shaft;
- wooden structures located inside the premises are in contact with the external walls;
- the wood is then painted or varnished.
It is recommended to prime all types of wood, regardless of their characteristics.
Advantages and disadvantages of applying a primer coat
Applying a primer under the varnish has the following advantages:
- a layer is formed that protects against rot, mold, fungus and rodents;
- the service life of wooden structures increases;
- wood can be used outdoors and in conditions of high humidity;
- the consumption of paints and varnishes is reduced;
- the strength of the wooden structure increases.
The disadvantages of the surface primer are:
- the cost of the work may ultimately exceed the costs incurred during painting without prior priming;
- finishing takes longer, because before varnishing the surface, you have to wait until the primer has dried.
Which primer is suitable
Due to the fact that different types of primer are applied under the varnish, the following circumstances should be taken into account when choosing this material:
- Scope. If priming of surfaces located on the street is carried out, compositions for facade work are used that can withstand atmospheric influences.
- Climatic characteristics. Some of the primers are intended for finishing wood used in high temperature and low humidity conditions. For painting surfaces in wet rooms, formulations with a hydrophobic effect are used.
- Drying time. The duration of this process determines the time of repair work. Alkyd primer dries faster than others.
- The type of material that is applied on top. For processing wood, it is recommended to use transparent primers that emphasize the structure of the surface. However, white compositions are used under the paint.
It is also recommended to pay attention to the composition of the primer mixture. If the material contains harmful substances, the finishing work should be carried out outdoors.
Composition varieties
The composition of the types of primers for varnishes is summarized in the table below.
| Type of mixture | Features |
| Acrylic | The composition penetrates deep into the structure of the tree, completely saturating the material. Acrylic primer is used for painting with any mixture. This product is odorless, dries in 1-4 hours and is for interior use. Water is used to modify the viscosity of the acrylic primer. |
| Silicone-acrylic | The silicone in the mixture increases the hydrophobic properties of the soil. Thanks to this material, it is possible to process wood used in damp rooms. A surface finished with such a primer ceases to absorb moisture. |
| alkyd | Such mixtures are used when the surface is further treated with alkyd dyes. Such formulations dry in 12-18 hours. Additionally, an alkyd primer can be applied to the painted surface. Mixtures containing color pigments, after drying, form a matte layer. |
| polyvinyl acetate | Soils of this type dry out in 30 minutes. To increase adhesion, it is recommended to apply a thin layer of PVA glue after processing. |
| Polyurethane | This is the most expensive type of primer for varnish. In such mixtures, solvents of different concentration are used. In addition, the primer does not contain pigments. |
| Shellac | This mixture is used to level a wooden surface. Shellac floors close natural pores, preventing resin from escaping. The mixture also creates an insulating layer so that the compound can be applied to raw materials. |
By properties and purpose
Primers used for varnishing are also divided into the following types:
- Antiseptic.The composition of such mixtures includes components that prevent the formation of mold and mildew, prevent wood from rotting and repel insects and rodents.
- Reinforcement. Such mixtures strengthen wooden structures, extending the service life.Such compositions are presented as deep-penetrating primers and increase the resistance of the treated surface to weathering.
- Hydrophobic. These primers are used for finishing wood used outdoors or in rooms with high humidity.
The type of primer is always indicated on the container with the mixture.
Ranking of the best brands
The rating presented is compiled on the basis of user reviews collected on the Internet. The floor qualities indicated in the list above are not suitable for all conditions of wood use.
Belinka base
This primer provides protection against:
- rot;
- mold formation;
- damage to the material by woodworms.
These characteristics led to a high price: 5 liters of Belika Base cost more than 2.6 thousand rubles.
Biofa 3754
A universal mixture used for the treatment of uneven surfaces and types of wood (mainly conifers) that absorb the applied compounds well. This material is recommended for interior and exterior decoration. Biofa 3754 does not contain solvents, which allows the mixture to be used in poorly ventilated environments. A 1 liter capacity of such a primer costs about 1000 rubles.
Tikkurila Euro Primer
Primer, or deep penetration primer, Finnish brand is used for finishing exterior surfaces. The material contains components that give the mixture antibacterial and disinfectant properties. Despite these characteristics, 3 liters of this primer cost 400 rubles.
"Texas"
Under this brand, they produce mixtures of primers intended for the treatment of porous surfaces. Such compositions can be used for:
- paint and varnish coatings;
- wallpaper;
- decorative tiles.
The floors of the "Tex" brand are distinguished by the following characteristics:
- suitable for surface treatment in rooms with normal or high humidity;
- fireproof;
- do not give off an unpleasant odor;
- dry quickly;
- strengthen wood and other porous materials.
"Tex" brand primers penetrate deep into the structure of the wood, binding the fibers together. Thanks to this effect, the indicated results are achieved.
Processing rules
Primers are applied the same way as paint coatings. However, in this case it is necessary to take into account a number of nuances that have a direct impact on the quality of the dried layer.
Material consumption
The consumption of the primer is indicated on the packaging and depends on various factors: application conditions, type of surface to be treated, etc. On average, when processing one square meter of surface, up to 80-120 milliliters of protective material are required.
Tools required
The type of wood priming tools are also selected according to the working conditions. To apply the material, you can use a spray, roller or brush. It is also recommended to purchase tools and accessories for cleaning surfaces from defects.
Surface preparation
Before priming the wood surface, you must:
- remove dust, dirt, fine hair;
- putty visible and minor defects;
- grind the structure.
If there are greasy stains on the surface, it is recommended to treat these areas with soapy water.Old paint should also be removed before priming the wood.
As a putty, it is worth using acrylic compounds that, after drying, retain the same elasticity and do not crack if the size of the treated material changes.
Layer application
Despite the fact that primers are available ready-made, it is recommended to carefully place the composition before application. After prolonged storage, a sediment appears at the bottom of the container. You need to work at temperatures from +5 to +30 degrees.
old painting
It is possible to prime wood over old paint if the type of material previously applied matches the protective mixture. But it is recommended to remove the peeled pieces before starting work and sand the surface with sandpaper. This will increase the adhesion of the wood and speed up the finish.
If the shade of the old paint and varnish does not match, the surface must be primed in 2 layers. Further work can be done after the protective composition has completely dried. If the characteristics of the old paint differ from those of the new (for example, alkyd paint has already been used and now oil paint is applied), the surface must first be heated with a dryer -building hair. After that, you need to remove the remnants of material, if necessary using a solvent.
If the floor does not contain substances that prevent the formation of mold, the wood must be treated with an antiseptic before applying the mixture.
On a cool tree
Primer can be applied directly to fresh wood after surface preparation. In this case, no further work is necessary.
Drying time and subsequent work
The drying time depends on the type of primer and the working conditions.The protective material gains strength in 0.5 to 18 hours. At temperatures above +25 degrees, this process takes less time. After priming, the wood can be treated with varnish or other finishing materials.
Mistakes when priming parquet and wood
When priming wooden structures, the following mistakes are often made:
- They use cheap soils, the characteristics of which do not meet the operating conditions. In this case, the varnish will begin to crack early, and traces of mold and rot will appear on the tree.
- Add additives. Mixing the soil with an antiseptic and other substances leads to the fact that the material loses its original properties.
- Improper surface preparation. This will shorten the life of the paint.
To avoid problems, it is recommended to select a primer for a specific varnish and wood service conditions.
Expert advice
Buying an expensive primer is not always justified. In some cases, inexpensive materials are better suited to the conditions in which the work is being done. When processing the ends, several layers of soil should be applied. This is because the tree here absorbs water better.
Before priming, the surface must first be sanded and then treated with a solvent. This will remove stubborn stains.