- Initial state of the walls
- Do you need a reinforcing mesh
- Working with corners
- Aligning planes
- Grouting and processing
Pasting walls with wallpaper is not the only finishing stage that you can do yourself. Surface preparation with local restoration and leveling with putty can also be done by hand, all the necessary materials and tools for this are easily available today..
Initial state of the walls
You should start by assessing the scope of work. Gypsum filler is a versatile material with good adhesion to most surfaces, however, long-term quality is guaranteed only if the substrate is properly prepared. There are five main types of defects: cracks, surface curvature, loss of strength due to erosion, biological damage, as well as dirt and residues of finishing materials.
Fighting cracks is carried out using primitive methods: cutting the plaster along the fault line with the formation of two wide chamfers, followed by impregnation with a primer and filling the crack. It is better to use the same composition as used for plastering work as a filling material. This is required in order to maintain uniformity and prevent further cracking. To accelerate the setting in the solution, it is allowed to add small portions of stucco..
It is not always possible to correct the curvature of the walls with a putty, the total layer of which should not be more than 5–8 mm. If the curvatures exceed 8-10 mm in the general plane, it is necessary to pre-level the wall with a plaster sketch with a minimum coating thickness; for this purpose, it is recommended to use gypsum plaster with the ability to apply in a layer of 6 mm.
The destruction of walls under the influence of moisture and oxygen, as well as the formation of fungus and mold, can only be eliminated by removing the destroyed or affected areas. With ordinary erosion, it is enough to beat off the crumbling layer and fill the depression with a similar composition, simultaneously bringing the repaired area into the common plane of the wall. However, if the fact of the development of harmful organic matter is on the face, careful drying of the wall with periodic impregnation with antiseptic agents is required to prevent the development of mold in the future. Sometimes the problem can be solved only after taking comprehensive waterproofing measures and eliminating excess moisture accumulation.
If wallpaper or paint remains on the walls, or there are dirty or oil stains, they should be removed in any way possible. Before puttingtying, the wall must be absolutely clean, while it is advisable to clean the surface to expose the base material.
Do you need a reinforcing mesh
You can often come across the opinion that wallpaper additionally strengthens the surface of the wall and therefore no reinforcing materials are required for filling. This is only partly true, this rule is not true for all types of bases and types of wallpaper..
As a rule, the reinforcement of the putty is practiced when preparing walls for painting in order to eliminate the formation of cracks that cannot be hidden in any way. The exact same approach should be practiced in the event that the decoration will be carried out with thin light wallpaper, for example, paper or vinyl on a non-woven backing. In addition to the fact that cracks can show through the canvas in the form of dark stripes, they can also lead to rupture of the wallpaper itself..
Solid wall surface reinforcement is not required in panel houses or if the base is sheet materials. It is also possible to avoid laying the mesh in the putty if the house is on a solid foundation and is made of large-sized masonry material with a small seam thickness, for example, from aerated concrete blocks. Reinforcement of the finishing layer is required when processing brick walls, especially folded in half-brick. You can also recommend strengthening the entire surface of the walls in secondary housing objects and private houses over 30 years old. In panel houses or if the base is represented by sheet materials, gluing of one or two layers of reinforcing mesh is required in the corners and joints.
What is mandatory when putting putty on walls is priming. It is carried out twice on the rough surface, and then in between before applying each new layer. For priming under the putty, use acrylic-based adhesive primers. Since the layer when puttying is minimal, it is not necessary to limit the moisture absorption of the substrate..
Working with corners
Putty under the wallpaper is done in separate sections, often individual work is carried out on each wall. And the preparation of each wall should begin with the design of the corners along the contour of the treated area. For a start, it would be a good idea to pull the lacing along the line of each corner to mark the most pronounced irregularities. It is especially important to do this in the corners between the floor and the ceiling for the correct installation of the skirting boards. Putty for removing corners is prepared in a slightly thicker consistency, the amount of water for mixing the mixture should be 5-7% less than the recommended by the manufacturer. Also, the mixture needs to be prepared in smaller portions, because the work has to be quite painstaking and the consumption when processing corners is almost twice lower than when puttingtying flat areas.
Guided by the marks on the wall, indicating the curvature of the plane and the thickness of the applied layer, it is necessary to make a preliminary calculation of the material. The corners are removed in strips 30–40 cm wide, respectively, a 200–250 mm spatula will be the most convenient for these purposes. The thickness of the applied layer is controlled visually, while it is necessary to periodically stretch the putty with long strokes with a swing of about 100–130 cm. After the surface of the putty has set, it is imperative to check the evenness of the angle line with a long rule. There is no need to remove scratches, shells and small ripples at this stage.
If the walls did not initially have significant curvatures, the corners can be covered immediately with a finishing putty. If irregularities of 3-5 mm are required to be corrected, it is better to fill the pits with starting plaster putty at the first stage, and then smooth the surface already at the stage of filling the common plane. As for the corner spatulas, it is advisable to use them only in vertical corners, as well as under the ceiling, but only if both converging planes are putty. In other cases, it is preferable to control the perpendicularity with a rectangular trowel, one of the corners of which is slightly blunt with a file.
Work on leveling the main plane is carried out with a division into sections of 1-1.2 m2. The total mass of the putty is immediately applied to the treated place, the consistency should be normal or slightly more rare. The putty should have a pronounced plasticity, but at the same time, excessive efforts should not be applied when smoothing out excess.
The technique of applying a uniform layer to the surface is not difficult, but you still have to “put” your hand first. Immediately after applying the bulk to the next area, smoothing is performed first in a horizontal direction, while each next movement with a spatula should be performed with an approach to the already smoothed area by about a third of the width. The optimal trowel size for such work is from 450 to 600 mm, depending on how much experience you have in the work and how strong your hands are..
After smoothing in the horizontal direction, the movement of the trowel changes to vertical. The same rules apply here: uniform movement along the entire path and orientation of the edge position along the already smoothed area. Each movement is performed not in a straight line, but along a slightly curved arc. In other words, both the shoulder and elbow joints must be simultaneously involved in the work. If the work is carried out in relatively small areas, the movement during smoothing is performed only from the elbow.
In the absence of experience in puttying, it is not necessary to strive to bring out the ideal plane when applying the first layer. The finishing gypsum putty is so good that it can be used to apply layers of tenths of a millimeter thick, achieving careful alignment at the intersection of strokes. You need to watch out for two things: a fairly rare consistency and the absence of protruding marks, pebbles and coarse dust on the surface. To do this, after each layer has dried, the wall needs to be cleaned, but without using an abrasive mesh, just roughly peel off with a spatula, at the same time polishing the edge of the tool.
Grouting and processing
As for sanding, it is performed at the final stage of surface preparation. To work with an abrasive mesh, be sure to use a flat trowel. Finish alignment is performed with precise single movements using the P60-P80 grid. It is not necessary to exert significant pressure on the tool, otherwise the float will begin to jump over the surface or form deep scratches. The final smoothing of the surface is recommended to be carried out with a finer mesh P120 in circular intersecting movements..
After cleaning, the walls must be cleaned of dust with a damp cloth, and then primed. The adhesion of wallpaper glue to gypsum putty is not satisfactory, however, gluing to an untreated surface can make the adhesion dead and it will be very difficult to soak and scrape off the base of the canvas when removing the wallpaper. For the final priming, use deep penetrating universal acrylic primers, impregnation with which will also provide additional adhesion between layers..