Why you need to putty the walls for painting
Puttying the walls for painting is necessary for the following reasons:
- The plastered surface is replete with large pores, which cause increased paint consumption.
- Even perfectly aligned plaster on the wall, upon closer examination, has flaws (small cavities, stains). Simple staining will not be able to eliminate these defects, but, on the contrary, will only emphasize them.
Therefore, prior to painting, the surface is recommended to be puttied. Using putty, you can achieve a smoother surface, which will save on paints and varnishes and get a clear color of the walls or ceiling.
What putty to choose
Putties are distinguished by the main component in their composition: gypsum, cement or polymers. They are produced in the form of a thick paste in plastic containers or as dry powder in bags. In the first case, the material is immediately ready for work, in the second - the powder will have to be diluted with water first.
The use of different options depends on the operating conditions, the purpose of the room and the type of walls intended for further painting. We consider each case in more detail.
Cement based
This type of putty is one of the most inexpensive finishing materials. The foundation is cement and fine sand. Released in bags of 25 kg. To obtain the finished material, dry ingredients are diluted with water in accordance with the manufacturer's instructions.
Scope: cement putties are suitable for processing walls outside and indoors, for subsequent painting with water-dispersion-based compounds. This coating perfectly resists moisture, and therefore can be used in the bathroom.
However, for decoration work indoors it is undesirable. Gray putty is a poor basis for high-quality painting.
Gypsum based
The best basis for painting rooms from the inside is gypsum putty, which forms a smooth white surface on top of which you can apply any kind of paint, as well as apply patterns.
Walls treated with gypsum plaster have an interesting feature: with increasing humidity in the room, they absorb some of the moisture and, conversely, the dry air in the room is slightly moistened, due to the return of excess moisture from the walls. However, the use of rooms with high humidity is not recommended.
Gypsum mixtures can be used as universal coatings, as starting or finishing options. Coarse particles are used to form the base layers, and finer particles are used for the final finish. It is not recommended to apply a layer of gypsum putty with a thickness of more than 20 mm.
In addition to the standard types of gypsum plaster, there are waterproof options that can be used to decorate the kitchen and bathroom.
Polymer based
Acrylic resins and latex are used as the basis for this type of putty. The most expensive type of putty. The best material for removing topcoat in critical areas. Sold in the form of a finished mixture in plastic packaging. Putty should be used fully after opening the package, as unused mixture is suitable for application to the surface for 1 day, after which it can be thrown out.
Polymer compositions are universal and are intended both for the base layer and as a topcoat. After a full set of strength, the putty surface is immune to moisture. Comparison of polymer and gypsum compositions we carried out here.
Necessary materials and tools
Before you putty the walls for painting, you need to acquire a tool and purchase material.
You need to purchase or rent the following tools:
- roller, from 200 mm wide, for work with a primer;
- brush, 100-150 mm wide, for working with the primer in uncomfortable angles;
- 20-30 l capacity for mixing putty;
- a hand or electric drill mixer equipped with a suitable nozzle;
- main spatula with a width of 500-600 mm;
- several spatulas from 100 to 250 mm wide;
- spatula for forming corners and inaccessible places;
- sandpaper with grit from 0 to 4, for grinding the treated surface.
The following materials will be required:
- filler mixture suitable for surface conditions;
- a primer;
- water.
Putty consumption calculation
When filling walls for painting, it is important to correctly calculate the volume of material. There is no universal settlement system, as in calculations, note the base material. So, for porous plastered walls, putty will be required more than for smoother walls made of gypsum plaster.
The average consumption can be calculated according to the following standards:
- the first (starting) layer is applied with a thickness of not more than 3 mm. Based on this, manufacturers recommend taking the calculation of material consumption as 1.2-1.3 kg per m2 surface to be trimmed;
- for the second (finishing) layer, the thickness of which does not exceed 1 mm, less material will be required - about 0.5 kg per m2.
The above example of calculating the consumption of material should be adjusted upward if there are significant deviations of the surface vertically or if a beginner takes up the matter, filling the walls with a do-it-yourself painting requires a certain skill.
The result of the calculation is usually rounded to whole packages. The standard weight of the dry putty mixture is 25 kg.
Preparatory work
Preparation of the base for puttying and subsequent painting is no less important than the procedure for leveling the walls. Thorough pre-treatment of the surface will increase the adhesion of the base and the leveling layer, as a result of which the surface after painting will be smooth and durable.
The technology of this type of work provides for the following preparatory steps:
- the base is cleaned of the old coating, nails and screws;
- it is recommended to plaster discovered large chips and pits with cement-sand or gypsum mortar;
- the cleaned and repaired base is coated with a primer. For concrete walls, a deep penetration primer is chosen. The primer must completely dry and impregnate the base, and therefore proceed to the next steps no earlier than after 5-6 hours.
Technology of puttying walls for painting
How to putty the walls for painting? Having dealt with the preparatory phase, the following operations are performed in the following order.
Start layer
The base, initial layer is formed after the final absorption and drying of the primer.
To prepare the working material, the dry mixture is poured in small portions into a container of water. The correct consistency of the solution is thick sour cream.
The procedure for filling the corners of the walls is discussed in detail here.
The finished solution is poured onto the main spatula and applied to the surface with a long continuous movement, trying to maintain the same distance from the wall to the tool blade. The thickness of the base layer is up to 3 mm. In corners and bottlenecks, smaller, suitable tools are used.
The finished surface should dry completely, after which it is trimmed with sandpaper and again coated with a primer.
Finishing putty
The formation of the final appearance is possible only after the complete drying of the base layer and primer. The layer thickness is up to 1 mm, but for beginner finishers it is often not possible to perfectly bring out the surface at a time, and therefore the appearance of a second finishing layer is permissible.
A new layer can be formed only after the previous one finally arises.
The lined dry surface is sanded with sandpaper or a special mesh and primed again, this time under the paint.
Nuances of puttying walls depending on their material
When preparing surfaces for further staining, the features of various substrates should be taken into account.
Drywall
The gypsum plasterboard base has a perfectly flat plane, but plastering the plasterboard to paint the walls is a mandatory requirement. It is especially important to seal the joints between the individual sheets.
Before the start of finishing work, the edges of the sheets that form the seam are cut at an angle of 45 degrees to get a convenient recess for filling the joints with putty. Then the entire surface is primed.
For processing joints, you need a sickle and special putty like Knauf fugen. Serpyanka is glued to the seam, after which the putty is carefully rubbed into it with a narrow spatula.
Puttying the entire surface is carried out according to standard technology. Other nuances of plasterboard puttying are described here and here.
Loggia or balcony
Finishing the exterior walls for painting requires the use of materials that are more resistant to external influences. So, for loggias and balconies, a facade putty containing cement is recommended. When using inexpensive brands, it should be remembered that when leveling the finished surface with sandpaper, individual fragments of the putty can crumble.
Plastered base
The plastered surface before filling is cleaned with a wide spatula, cutting off all the influxes. If in some place the plaster crumbles, this place should be cleaned and leveled with a plaster mixture.
The old coating is removed, the surface is leveled - then it is necessary to impregnate the finished base with a primer.
When working with a plaster base, three leveling operations are performed:
- For the first time, chips and dents are removed.
- The second layer achieve the final alignment.
- The third layer eliminates all the minor flaws.
All layers - up to 1 mm.
Concrete base
Putting filler mortars on an unprepared base is not recommended. Prior to puttying, it is advisable to treat the walls with plaster mortars.
When the wall is even - the putty is applied in three layers, with the obligatory preliminary surface treatment with a deep penetration primer.
Painted surfaces
Putty previously painted plane is undesirable. If such a need still arises (for example, in the bathroom), the base is treated with soil and only after it has completely dried can we start puttying in three layers.