4 types of primers for walls for painting and calculation of consumption, how to apply
Using a paintable wall primer achieves excellent results. This special composition is often used for finishing work. With its help, it is possible to strengthen and level the base and improve the adhesion between the layers of facing compounds, preventing the delamination of paints and varnishes. In order for the substance to give the desired effect, it is necessary to follow the rules of its application.
The importance of priming walls for painting
Using a primer achieves a variety of results:
- Strengthen the base. The material increases the strength of weak, loose and porous surfaces. Deep penetrating substances are particularly effective in this regard. They can deepen by 80 to 100 millimeters, while conventional formulations penetrate a maximum of 20 to 30.
- Increase adhesion or adhesion of finishing material and base coat. Using a primer keeps the stain on the surface better, preventing it from flaking and cracking.With subsequent repainting, the base will be easier to prepare for work.
- Reduce hedging costs. After the end of treatment, it is possible to significantly reduce the absorbent characteristics of the base. This reduces the cost of the finishing agent by 30%.
There are also substances that have special characteristics. They help to increase the moisture resistance of the coating and prevent the formation of mold.
Varieties of primer and recommendations for choosing
Primers differ in their composition and characteristics. It is allowed to apply substances with different properties under the paint.
water-based
It is quite an expensive finishing material. Applying the primer helps reduce the absorbency of the substrate and makes the application of the colorant more uniform. In addition, the composition increases the strength of the coating and increases the service life.
It is necessary to apply the primer with a brush. In addition, it should be done in 1 coat, which will help hide all the irregularities, but will not form uneven buildups of primer. After the composition has dried, the dye can be applied. And it must be done in 2 layers.
Acrylic
This universal composition can be used for different types of bases - concrete, wood, brick. It is also suitable for application on aerated concrete and chipboard. The primer can be used for glass and plaster surfaces.
The primer is odorless and dries quickly.
You can get a good result in just 2-3 hours. The composition contains acrylic polymers. If the product contains an aqueous dispersion, it is permitted to use it as a base for water-based paint.
Oil
This substance has a high degree of adhesion. This helps to increase the strength of the coating, making it smoother and less porous. The composition adheres perfectly to the surface, so it is often used for decoration.
Silicate
This substance has excellent moisture resistance and normally perceives temperature fluctuations. In addition, it has high resistance. The substance can be used for application to brick and plaster surfaces. Most often, primer is used on balconies and in bathrooms.
Tools needed for work
To apply the primer, you will need the following tools:
- brush;
- container;
- roll;
- spray.
The set of tools may differ depending on the goals and objectives. Thus, it is worth applying the composition to a brick surface with a brush, while a roller is more suitable for smooth walls or plasterboard. The spray gun is also considered an effective tool, but it is used less often, since after using it it becomes difficult to clean the premises.
Surface priming technique for painting
In order to properly prepare the walls, it is important to follow a number of recommendations. In this case, it is necessary to pay attention to the choice of the type of soil and the technique of its application.
We calculate the material consumption
To determine the approximate amount of material, simple calculations should be made. It is recommended to first calculate the area to be primed. To do this, the height of each wall must be multiplied by the length, and then add the resulting values. In this case, be sure to subtract the area of windows and doors.
Next, it is necessary to determine the number of layers required. If only one is enough, it remains to multiply the resulting number by 1.15 - this factor makes it possible to obtain a certain stock of material.
If you plan to apply 2 or more layers of primer, the resulting value should be multiplied by their number, and then by a factor. This will help you calculate the approximate amount of land to focus on when buying.
Preparatory work
A coat of primer helps to make the surface less hygroscopic and to ensure even application of the colorant. Also, the substance increases the wear resistance parameters and increases the service life. To achieve these results, it is important to do the groundwork correctly. To do this, you must do the following:
- Spread plastic wrap on the floor. It is also necessary to de-energize sockets and switches. This will help prevent short circuits in the event of moisture or dye ingress. It is also necessary to move furniture aside and put on protective clothing.
- Before using the primer, the walls should be cleaned of old wallpaper, tiles, whitewash, putty or other finishing materials. In this case, it is worth using appropriate tools - a spray gun, spatula, chisel and scrapers. To remove some finishing materials, the surface should be thoroughly moistened. To do this, it is recommended to use a roller with thick bristles. A foam cushion is also suitable for this purpose.
- Repair damage to walls. With deep cracks, they need to be widened and deepened. This will allow the repair mortar to penetrate and tighten the edges. The defect must be cleaned of dust, cement chips and impregnated with a primer. To seal the cracks, you will need a cement mortar, a composition based on gypsum, a polymer putty. It is also allowed to use mounting expansion foam.
- Check the wall for gaps and irregularities. This is done using a plumb line and a building level. It is recommended to attach the tools to the surface and identify the differences. If irregularities exceeding 5 millimeters are found, the wall must be completely leveled. Differences of 2-3 millimeters can be eliminated by applying a thin layer of plaster or putty.
- Dust with a brush and degrease the support. For this purpose, it is permissible to use white spirit or acetone.
Primer application and number of coats
It is necessary to apply the primer with a roller. To begin with, it is recommended to fill the paint tray with the composition, moisten the roller on both sides and wring it out on the grid. Then spread the mixture evenly over the surface. Thanks to this, it is possible to obtain a high-quality result.
When applying the first coat, the roller should move up and down. This will help avoid smudging. Difficult places should be primed with a brush.
After application, the layer must dry well. The exact time is indicated on the packaging. However, it may change depending on the temperature and humidity of the room.
It is important to take into account that the floor must dry naturally, so it is forbidden to use hair dryers or building heat guns. Such devices will lead to disruption of the technological process.
Once the first coat is dry, the second can be applied. It is important to do this as evenly as possible to avoid the risk of sagging.
Drying time
This is an important parameter that affects the quality and rate of repair. The drying time of the primer is always indicated on the packaging.Also, the manufacturer gives the time interval during which the composition will freeze. This is due to the fact that the speed of hardening is associated with the influence of various factors. These include in particular the following:
- Indoor humidity and temperature settings. Suitable indicators include 60-80% humidity and a temperature of + 15-20 degrees. Until the primer is completely dry, the room should not be ventilated. This must be done before applying the substance. If this recommendation is not followed, there is a risk of cracking.
- The quality and appearance of the base. Dry, porous surfaces dry much faster. If you need to speed up the drying of the primer, the base should be degreased before using it.
- Composition of substance. Products containing solvents, which volatilize easily, harden the fastest. This also applies to formulations with solid components.
- Number and thickness of layers. With each subsequent coat, the drying time of the walls increases.
It is impossible to determine the specific drying time of the floor before painting. This must be assessed visually. It is important to wait the interval recommended by the manufacturer and then touch the surface with your hand. If moisture is felt, painting should be postponed.
How long does it take to paint?
On average, the soil dries for 6-8 hours. After the specified time has elapsed, it is permissible to proceed with the application of a dye - water-based, oil-based or other.
Is it possible to paint without a primer
The application of the primer does not affect the appearance of the surface. However, its use should not be neglected. First of all, the use of a primer affects paint consumption.If you do not use this tool, the cost of paints and varnishes increases by 20%.
When painting the walls without a primer, difficulties arise if it is necessary to change the color when renovating the interior. When fresh paint is applied, it will peel away from the finishing putty. In this case, the voids will have to be repainted and wait for drying. Also, stain that has been applied to the wall without a primer will not adhere well.
Advice from the masters
Before applying the primer, it is important to read the recommendations of qualified craftsmen:
- It is necessary to apply the primer only after the solution has completely dried - after 2-4 weeks.
- When decorating facades, it is important to ensure that they are dry and not very hot from the sun.
- If you need to dilute the primer, it is important to use products recommended by the manufacturer.
- When processing surfaces with high absorbent properties, the primer should be applied in 2-3 layers.
- It is worth starting to paint after the time it takes for the floor to dry completely. It differs depending on the composition and can last from 2 to 24 hours.
- It is important to treat knots before priming the wood. They need to be heated with a heat gun, collect the resin with a spatula, process with a solvent and apply shellac.
Using a primer to paint the walls increases the adhesion of materials and makes the surface smoother. To achieve the desired effect, it is important to strictly follow the instructions for use of the substance.