In what cases can you do without priming
When making repairs in the apartment with their own hands, the owners often doubt whether it is necessary to prime the drywall before the putty? There are different opinions, but master finishers argue that in most cases, priming of drywall is necessary. To exclude disputes, there are three situations where the treatment of GCR with a primer is not mandatory:
When the walls of the room are sheathed GKLV. In rooms with high humidity, moisture-resistant sheets of drywall are used to level the walls. They can be distinguished by green color. Due to the processing of the material with special moisture-resistant compounds, GKLV does not absorb moisture, like a standard drywall, which allows it to be fixed in the bathroom, toilet and kitchen. In addition to protection against moisture, moisture-proof plasterboard sheets are treated with antiseptic agents to protect against the appearance of fungus and mold.
It will not work to apply the primer to moisture-proof drywall, since the treated surface will repel the liquid solution, preventing it from penetrating into the material - the primer will simply drain off the wall. GKLV could be treated with non-water-based primers, but they cannot be used inside residential premises.
When it is necessary to prepare a perfectly flat surface for applying paint. In this case, for the preparation of the base, putty finely ground compositions are used, which are the finishing ones. Starting putty is not intended for smooth surfaces and cannot be used for applying paint.
The primer of the drywall before putty for subsequent painting involves puttying in 2-3 layers, since the application of the finishing putty on primed sheets is not done. If you refuse to use the primer, you can immediately apply the finish layer and start painting the surface - the quality of work in this case will not suffer.
It should be remembered that, abandoning the priming of the entire surface of drywall, we must not forget about the processing of the fixation points of the sheets to the frame and the joints. The heads of the screws are painted with oil paint, after which they are putty. This measure is necessary to prevent the appearance of rust spots on an already painted wall surface.
It is necessary to refuse to apply the primer when in the coming years it is planned to replace ordinary plaster with wet.
When a primer is definitely needed
We figured out in what situations you can do without a primer for drywall substrates. Now we will explain why, in other cases, the use of a primer is necessary.
The primer, or primer, is used to increase the adhesion of the base to the finishing materials. A primer layer applied to the base evens out the surface and fills small pores, which saves on the finish.
Apply a primer to cement, lime and gypsum substrates. But is it necessary to prime drywall before puttying? Modern finishing technologies imply the mandatory use of drywall primers to achieve the following goals:
- increase the level of adhesion of the base and topcoat;
- reduce the consumption of finishing materials used for application to the base;
- Facilitation of work with finishing compounds;
- strengthening the base structure.
Properly applied primer on drywall allows you to remove old wallpaper and ceramic tiles during repairs without compromising the cardboard that protects the gypsum base of the sheet.
It is also important to prepare the base from drywall for further decoration with decorative plaster. If there is no film on the surface of the sheet that is impervious to moisture (a primer forms it), the hydration process of the decorative plaster will be disrupted. As a result, the service life of the finish will decrease, peeling and cracks may appear.
Primer Guidelines
To choose the right primer, you need to figure out what types of primers exist and for which surfaces they are intended.
On sale you can find the following types of primers:
- acrylic. They are used for processing almost all types of surfaces. Thanks to the water base, acrylic primers have no toxic fumes and are ideal for interior use. Drying time - 3 hours;
- phenolic. Designed to protect metal and wood structures, but can also be used to process drywall. It must be remembered that phenolic primers are available in two types - for external and internal use. The use of a primer for outdoor indoor use is prohibited due to the strong toxicity of the composition;
- alkyd. Designed for wood processing;
- glyphthalic. Are made only for processing surfaces outdoors. They are not suitable for internal work, although they have the highest protective and leveling ability;
- perchlorovinyl. Also refer to primers for outdoor use. They are designed for the treatment of concrete and brick substrates;
- polystyrene. They have increased toxicity. They can be used for processing wooden substrates and plasters outside buildings;
- polyvinyl acetate. Designed to prepare surfaces that are planned to be painted with polyvinyl acetate coloring compounds.
The right type of primer improves the finish of walls and ceilings. The primer closes the pores, evens out the surface of the base, reduces material consumption and shortens the drying time.
When choosing a primer, the following features should be considered:
- whether this type of primer is suitable for application on drywall;
- whether this type of primer is suitable for putting under putty;
- what types of work is the primer intended for - external or internal.
Which primer is better? Taking into account all the restrictions, we can conclude that Acrylic-based water dispersion primers will be the best option for GCR treatment..
After choosing the type of primer, you should compare the technical characteristics of the primers that can be found in stores. Important points when comparing are:
- manufacturer. With a relatively small difference in price, it is better to choose well-known brands - Knauf, Tikkurila, Ceresit;
- how many times you need to apply a primer to the surface to obtain the desired result;
- consumption per square meter.
Knowing the area to be treated, the consumption per square meter and how many primer layers to apply, you can choose the most advantageous packaging with the material.
For internal work, it is better to buy ready-made liquid compositions that have increased hiding power and low consumption.
Drywall Primer Technology
The priming of gypsum plasterboard surfaces can begin immediately after completion of installation work. To prime GKL, you will need to purchase the following materials and tools:
- ready-made liquid primer:
- roller on a long handle;
- brush 100-150 mm wide for corner processing;
- capacity for work with a primer. It is most convenient to use a special cuvette with a corrugated wall to squeeze out excess liquid solution;
- respirator for respiratory protection;
- safety glasses for eye protection;
- overalls and gloves to protect the skin.
Step-by-step instructions for applying soil on a drywall surface:
- The primer is prepared. If a solution has been purchased that requires additional preparation, it is placed in a separate container and dissolved with water in accordance with the instructions.
- A portion of the finished solution is poured into a cuvette. Having evenly moistened the roller, they begin to distribute the primer on the surface of the wall or ceiling. All parts of drywall should be carefully treated. Particular attention should be paid to the seam between the individual sheets.
- Hard-to-reach places (corner joints, adjacencies to the floor or ceiling) are processed with a brush. The uniformity of the coating allows subsequently high-quality application of putty.
- If the instructions for the primer say that it is necessary to apply two or three layers to the surface, the next layer is applied only after the first has completely dried.
- After the last coat of primer has dried, you can begin to putty. To obtain a better coating, it is recommended to apply the primer to the rough coat of the putty after it dries.