If we are not talking about a new building, when carrying out repair work, you have to decide what to do with the old coating on the walls. Ideally, it should be removed, but this is a laborious process that lengthens the repair time. If paint has been applied to the walls, there is a desire to leave it. Let's find out in what cases it is possible to glue wallpaper on water-based paint and how to do it in order to achieve a high-quality and durable coating?
Will the wallpaper stay on the "water emulsion"?
It is permissible to glue a new finishing material directly onto the old paint, but only under certain conditions, the main of which is the strength of the paintwork.
Consider the cases when it is necessary to remove paint from the walls:
- If it does not adhere well to the surface, it peels off from it in large fragments.
Sometimes it is difficult to visually determine how firmly the painted layer holds. You can check with adhesive tape: a piece of it is glued to the wall, and then comes off. The absence of paint particles on the adhesive tape is an indicator of the strength of the coating.
- The surface of the paint was covered with a network of small cracks and chips.
- There are pockets of mold or fungus on the wall.
In all other cases, the application of wallpaper on a "water-based" or oil paint is possible with appropriate preliminary preparation.
Checking the old coating
What can happen if you stick wallpaper directly on a layer of paint? A happy outcome in this case is almost guaranteed to be excluded. The canvases can simply fall off due to low adhesion to the wall, peel off along with the paint, and become covered with cracks. Therefore, checking and preparing the walls is mandatory.
First of all, the type of paint is determined. Not only the properties of the coating depend on it, but also the technology of its preparation before gluing wallpaper on painted walls.
- Oil paint has a specific smell, forms a thicker layer and peels off the wall in separate fragments much easier.
- Enamel is similar in properties to oil, but usually holds much better.
- The layer of water emulsion, acrylic or latex, has a smaller thickness. Its strength of adhesion to the wall is much higher.
After making sure that the old paint is indeed water-based, you should carefully examine its surface. At this stage, they look for the signs described above, and also check the strength of adhesion to the base of the wall with adhesive tape.
The technology of gluing wallpaper on water-based paint
Before wallpapering, you can not remove the paint layer, subject to 2 conditions:
- with firm confidence in its strength and quality;
- with strict adherence to technology during preparatory work.
Disadvantages of walls painted with dispersion dyes may already be revealed during the preparation process. So, when applying a primer, which is a mandatory step, peeling of the surface or the appearance of blisters can be observed. In this case, the removal of the old finish is mandatory.
Materials and tools
Materials may require:
- Putty to eliminate minor defects on the walls.
- Primer. Its application is mandatory. It is better to give preference to deep penetration compositions based on acrylic. If the colored wall has a dark tint, then with the help of a pigmented white primer it can be “painted” so that the old coating does not show through under the light canvases.
- Non-woven wallpaper. They are preferred for use in this case: lighter than vinyl and stronger than paper.
- Adhesive composition. Better from a reputable manufacturer. This is the case when a low price most likely indicates low quality. Save on wallpaper glue is not worth it.
Tools for work can be found in the arsenal of even a novice master:
- Brush or vacuum cleaner.
- Spatula and grater. It will be required if you have to eliminate minor wall defects.
- Roller and brush. Needed when priming, as well as in the process of fixing wallpaper.
- Level, sharp scissors, paint knife, pencil.
- Rubber roller. It is convenient for them to smooth the panels, preventing the formation of bubbles.
Wall preparation
Stages of work:
- If necessary, smooth and level with putty irregularities and cracks.
- The entire surface is rubbed with fine sandpaper or an abrasive mesh. This will increase the adhesion of the smooth coating.
- The walls are free from dust. You can use a brush, but a vacuum cleaner is better.
- A deep penetration primer is applied. This operation must be repeated at least twice, and in perpendicular directions. The second time primed only after the first layer is completely dry.
After such processing, pasting is carried out in a standard way, guided by the rules for the selected type of wallpaper.
Gluing process
Wallpapering Instructions:
- With the help of a measuring tool, lines are laid on the wall that will help to correctly place individual fragments. This is much more reliable than gluing "by eye".
- Pieces of wallpaper are cut to the desired size. For insurance, it is better to leave a small margin of 2-3 cm.
If there is a pattern, a thoughtful cutting of the roll is required. It is often more profitable to cut off the necessary fragment from a new pipe than to cut and discard significant pieces from the one that has been started.
- According to the recommendations of the seller indicated on the package, wallpaper paste is prepared.
- Glue is evenly applied to the fragment with a roller or brush. At sticking non-woven wallpaper, most preferred for this case, the wall is also covered with adhesive, avoiding drops or smudges. The process of gluing vinyl on a paper basis is described here.
- The piece is carefully applied to the marks on the base and smoothed out with a rubber roller, a special spatula or a cloth in the direction from the center to the edges. So the folds are removed and air is expelled from under the surface of the wallpaper.
When creating a coating that has a common pattern and consists of separate stripes, an important point is the quality laying of the first fragment. Its oblique location will entail a distortion of the rest, which is difficult or almost impossible to correct.
- Similarly, adjusting the pattern, the following strips are glued. To make the joints stand out less, it is better to start the process from the window.
- After the wallpaper dries, the excess is removed with a paint knife. More evenly, it will turn out to be done on a plinth or baguette.
A qualitative result is impossible without creating an appropriate microclimate in the room: drafts are excluded for the entire process and a temperature of +18 °C is provided. At higher temperatures, wallpaper may lag, at lower temperatures it will not dry well.
It will be easier to identify surface flaws even during the pasting process if you provide lighting in the room from several sources so that the rays fall on the wall at an acute angle.
What if the paint fails the test?
In this case, it is necessary to carefully remove the coating from the water-based emulsion, trying not to damage the base of the wall. The easiest way to do this is with a spatula, moistening the surface with hot water. This is the safest and most environmentally friendly way.
In the future, the wall is leveled, primed and the wallpaper is glued in the usual manner.
If the paint turned out to be oily
A poor-quality, poorly adhered layer of such a coating is removed in the most appropriate way. Oil paint is more difficult to remove from the wall than water-based paint. Methods for removing old paint of different types are described in detail. here.
A durable old oil-based coating is pasted over with wallpaper after preparation: to increase adhesion, the wall is rubbed with coarse sandpaper, and then covered with a primer layer. On such a surface, the wallpaper will hold firmly and for a long time.
