Types of drywall primers and how to do it yourself, their use
Using drywall, you can level the walls and ceiling, as well as create custom designs such as built-in shelves and the like. After installation, this material forms a "rough" base on which the finish is laid on top. To increase the service life of the latter, special drywall primers are used, which harden the surface.
Does drywall need to be primed?
The walls and the ceiling are sheathed with plasterboard under:
- wallpaper;
- Paint;
- putty and plaster;
- floor tile.
The primer is used to increase the level of adhesion of the materials applied on top, which increases the strength of the finish and protects the coating from the negative influence of external factors.
At the same time, this procedure is not carried out if moisture-resistant drywall was used when leveling walls and ceilings (marked as plasterboard). Such material is treated during production with special impregnations that prevent the primer from penetrating deep into the surface.
Primer properties and functions
Surface priming is done in order to increase the adhesion, or degree of adhesion, of the applied materials (glue, plaster, paint, etc.) with the treated drywall. But, depending on the characteristics of the impregnation applied, this tool creates a layer with the following properties:
- water repellent;
- prevents the development of mold and mildew;
- fight against the fire;
- protect from insects.
There are also deep penetration primers. Such mixtures protect the treated surface from the inside.
Primers give the surface both some and all of the above properties. However, these universal mixtures are inferior to specialized mixtures in terms of characteristics (intensity of protection). That is, bathrooms are recommended to purchase formulations that have moisture-protective properties, and not combine all these characteristics.
Advantages and disadvantages of an applied primer coat
Surface priming is a mandatory procedure performed in order to prepare drywall for finishing. This operation is carried out in order to:
- Create a layer of moisture protection, including at the joints of the gypsum board, where mold usually begins to grow.
- Strengthen the base.
- To increase the adhesion of the support to the applied finish, thus increasing the life of the latter.
- Reduce material consumption. Thanks to the primer, in particular, the paint is evenly distributed over the surface.
- Hide minor drywall flaws. This is necessary when painting walls and ceilings.
The primer is able to partially level the poor quality of the used tile or wallpaper glue. This is also achieved through increased grip.
The only drawback of the primer is that the duration of repair work increases by the time required for the applied composition to completely dry.
Suitable soil types and selection recommendations
According to the basis, drywall primers are divided into the following types:
- Acrylic. A versatile mixture that does not emit unpleasant odors and is environmentally friendly. The acrylic primer dries in 2-3 hours and is applied before and after filling. The layer that forms this composition is breathable.
- Phenolic. These compounds are less commonly used to treat drywall. Phenolic primers contain toxic substances, so you need to work with such a mixture with a respirator.
- Alkyd. They are used only for processing drywall. That is, an alkyd primer cannot be applied over putty.
- Dispersed in water. Such soils dry quickly, do not burn and are harmless to humans. Compositions of this type are distinguished by deep penetration.
When choosing a composition, it is necessary to take into account the material on which the primer will be applied:
- under the wallpaper - deep penetration dispersed in water or acrylic;
- under the tiles - deep penetration of acrylic;
- for water-based paint - universal;
- under putty - dispersed in water with acrylic polymers.
If the primer is to be painted, it is recommended to purchase low penetration compounds with little adhesion. This will save on finishing the premises. For bathrooms and other rooms with constantly high humidity, you need to purchase formulations with water-repellent properties.
Homemade Mix Recipes
For drywall, a deep penetration primer is suitable, which can be done by taking the following components:
- PVA building glue (1 liter);
- water (8 liters);
- cement or crushed chalk (100-200 grams).
First of all, you need to mix the first 2 components in a container to get a homogeneous composition. Then you need to add cement and repeat the operation. Further, this liquid must be filtered through a gauze bandage, removing undissolved substances.
The basis of such a primer is glue, which protects the surface from contact with moisture and increases the adhesion of drywall. The other two components are needed to improve penetration and adhesion to the material.
Drywall can also be primed using a mixture of the following components:
- wood glue (0.5 liters);
- copper sulfate (100 grams);
- water (7 liters);
- Laundry soap 65% (1 packet).
Soap must be ground beforehand and added to boiling water. Then you need to reduce the intensity of the fire and mix the liquid with the remaining ingredients. After that, the composition should be kept like this for half an hour and strained through cheesecloth.
This primer strengthens the surface to be treated and prevents black mold.
Application rules
Priming drywall is carried out according to the same algorithm as painting. In this case, the manufacturer's recommendations for the use of the composition should be taken into account.
Calculation of consumables
Tools required
To prime the drywall, you will need:
- a brush (used to treat hard-to-reach places and joints) and a roller;
- container for mixing primer;
- ability to wring the floor.
It is also recommended to prepare a cloth and other surface cleaning tools.
GLK preparation
Before applying the primer, it is necessary to remove dirt and traces of grease from the surface of the drywall. Depending on the type of composition used, the GLK plates in the places where the self-tapping screws are putty before or after processing. If an acrylic primer is used, the last procedure can be done at any stage.
In the event that wallpaper is applied to drywall in the future, the following should be done:
- Apply the first primer with antiseptic ingredients.
- Putty and align the places with self-tapping screws and gaskets.
- Dust the surface.
- Apply a second coat of primer.
Before tiling, it is also necessary to first apply the first primer, then the reinforcing mesh and the second.
Primer application and drying time
It is recommended to stir the primer until a homogeneous composition is obtained before surface treatment. Then the liquid is poured into a prepared container and evenly distributed over the surface using a roller.
Drywall should be primed in 2 or more layers (according to the manufacturer's recommendations), waiting each time for the previous one to dry. At this stage, it is important to treat the joints with a brush so that there are no more "voids" where mold can appear.
It is recommended to work at a temperature of 16-20 degrees. The drying time in this case is 2-4 hours. Acrylic primers gain strength faster, and deep penetrating compounds - 2-3 hours longer.
What mistakes beginners make
Often when priming a surface, subsequent coats are applied before the previous one dries.Due to this, the mixture does not have time to acquire the specified strength.
The second common mistake is non-compliance with the rules for applying composition. Often novice craftsmen miss the joints. But this is where water collects, creating conditions for mold to grow.
The third mistake is not following the order of work. In particular, some primers cannot be applied to the putty that covers the screws. This error is most common when preparing drywall for wallpaper. Failure to follow this rule will reduce surface adhesion. This is especially dangerous in cases where thick wallpaper is pasted over drywall.
Advice from the masters
When priming surfaces, follow the manufacturer's recommendations. These are indicated on the packaging. This will avoid many errors.
Beginners are advised to purchase a primer containing coloring pigments. After applying such a mixture, untreated places are immediately visible on the wall and ceiling. In this case, the earth does not appear on the surface after finishing. This feature is explained by the composition of the color palette. Due to this, the primer loses its tint after drying and becomes transparent.
In order for the composition to acquire the specified strength, it is recommended to wait at least a day after preparing the surface, and then proceed to finishing. Regardless of the type of floor used, work should be carried out in a well-ventilated area.
Also, when calculating the amount of protective composition, 10-15% should be added to the volume that the manufacturer recommends applying to a given area.