How To Putty Plasterboard Walls Under The Wallpaper And Why

2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54

• Why putty drywall under the wallpaper
• Which putty to choose
• Surface preparation
• Pre-filling
• Final plasterboard filler

After sheathing the walls with GKL sheets, their surface is smooth and even. Therefore, those who independently make repairs in an apartment or house often have a question: is it necessary to putty drywall under the wallpaper. It would seem that it is enough just to close up the seams and caps from the screws, and paper to paper is perfectly glued. But, like any work, preparing drywall for wallpapering has its own characteristics that affect the quality of the final wall decor.

Why putty drywall under the wallpaper

Do I need to completely putty drywall under the wallpaper? There are at least two important reasons for this operation:

1. If the wallpaper is made in light colors or has a small thickness, then through them, the joints and any irregularities on the surface of the gypsum board will clearly show through. The result will be an impression of inaccuracy, which can be avoided by filling the entire drywall.
2. But the main reason that you need to putty drywall under the wallpaper lies in the fact that any decor on the walls can get bored over time. This means that the old wallpaper will have to be removed, which is not so easy to do if there is no layer of putty underneath. Removing the old coating can damage the drywall sheets to such an extent, otherwise you will have to align or even change. So doubts about whether it is necessary to completely putty drywall under the wallpaper should not arise at least in order to avoid unnecessary work in the future when replacing them.

The walls should be completely putty under the wallpaper if thin wallpaper is used or the surface is poorly prepared.

Which putty to choose

There are no fundamental recommendations which putty is best suited for drywall under the wallpaper. The special qualities of the mixtures, for example, fire resistance or frost resistance, do not play any role in this case, it is more important to pay attention to the purpose of the putty and the room in which it will be used. So, gypsum putty is more suitable for dry rooms, since it is afraid of large changes in humidity and may crack. Therefore, for a bathroom or kitchen, it is better to use a cement-based putty.

The leveling compound is good for sealing seams, cracks and dents. It has a coarse-grained texture, therefore, as a finishing one, it is suitable only if the wallpaper material has a large thickness and density.

The universal polymeric putty can be used both for leveling the surface and for finishing. It is suitable for rooms with any humidity. And its consumption is less than that of other types of putties.

Choosing what kind of putty to putty drywall under the wallpaper, it is better to give preference to the dry mixture, since it is stored longer and can be used dosed, mixing as much as needed. Usually, the manufacturer of the putty indicates on the packaging instructions for working with the mixture and the required proportions, while you need to pay attention that some putties must be infused. To obtain a homogeneous mass, it is advisable to use a construction mixer, but if it is not there, then a special drill attachment will do.

Surface preparation

Before starting to putty drywall, it must be cleaned of dirt and dust and carefully inspected for scratches, deep dents and protruding screws. An ordinary wide spatula can help with this. Driving it along the plane of the plaster, it is easy to detect various defects.

Unscrewed self-tapping screws should be tightened with a screwdriver, slightly drowning their heads into the top layer of drywall. If there are screws, the caps of which have entered too deeply into the body of the gypsum board (more than half the thickness of the sheet), then they must be removed and screwed in a new place, at a distance of at least 50 mm from the old attachment point. A smaller distance is not recommended, as a crack may form between the holes, which is likely to spread further, which means that this sheet will need to be replaced.

If the drywall sheets at the joints do not have a factory bevel, then their edges must be cut at an angle of 45 degrees. This is necessary in order for the putty to penetrate deep into the seam. In addition, there should be no delamination of the paper from the gypsum at the edges of the sheets. If such a defect is found, the detached cardboard must be carefully trimmed with a knife, and the place must be primed. In more detail, how and with what to cover the joints of drywall.

After visual inspection and detection of all flaws, the plasterboard wall must be primed. It is better to use water-based mixtures as a primer, since they soak only the cardboard layer and do not deform it. The primer should be applied evenly over the entire surface of the drywall, in a thin layer. When it is completely dry, you can start pre-filling.

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Pre-filling

Do-it-yourself preliminary plastering of drywall under wallpaper is aimed at leveling the surface and includes:

• sealing seams and joints;
• filling screws;
• filling corners;
• alignment of dents and other defects.

Putty of seams between sheets and joints of gypsum with walls, ceiling and floor should be started with the sticker of reinforcing tape - serpyanka. It is important to glue it so that the groove to be sealed is in the middle of the tape. The putty can now be applied. The work is carried out from top to bottom, while it is convenient to use two spatulas - narrow and wide. The first can fill the seam with a mixture, and the second can level it along the surface with longitudinal movements. Putties should not be spared, since when it dries it gives significant shrinkage. The result should be a completely filled seam, with no gaps or visible indentations. It is better if there is a slight excess of putty - then it can be removed with an abrasive mesh.

The putty is applied crosswise on the screws. So it completely fills the grooves from the fastener caps and hides its heads.

When plastering drywall walls under wallpaper is performed, perhaps the most difficult operation is to putty the corners … For the outer corner, a perforated corner made of aluminum or, if the corner is arched or curved, plastic is often used. Setting up such a profile is easy enough. To do this, you need to attach a corner to the place in which it is mounted. Make marks with a pencil, then cut the drywall along lines about 3 mm from the marks as viewed from the corner, then use a chisel to remove the cardboard to a depth slightly deeper than the thickness of the corner. The resulting grooves are filled with putty, and then the corner profile is pressed into them so that it is slightly deeper relative to the plane of the walls. The putty protruding through the perforation is smoothed with a wide spatula with the addition of a mixture to obtain a surface aligned with the plane of the sheet. Video about plastering walls and ceilings.

The inner corners are slightly more difficult to putty. First, they, like the seams, are reinforced with a serpentine. Secondly, in order to evenly remove both adjoining sides, they are putty in turn - first one side, then, after the first is completely dry, the second. The work is facilitated by a special spatula for corners, which can be easily found.

Dents, deep scratches and other defects are repaired in a standard manner. Moreover, if the putty needs to be applied in several layers, then each subsequent layer is applied only when the previous one dries. To assess how smoothly the wall is putty, you can use the usual building level.

After finishing the preliminary filling of the drywall walls, it is necessary to wipe them with a sanding net, clean and re-coat with a primer.

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Final plasterboard filler

Finishing plasterboard under the wallpaper will allow you to get a flawless surface for further finishing. For this stage, a wide spatula is suitable, and the mixture itself should be comparable in density to sour cream.

The putty is applied with wide sweeping movements, so that its layer is as even and thin as possible. If, nevertheless, it is not possible to avoid small beads, they are later smoothed with sandpaper. The main thing here is accuracy, slowness and thoroughness.

After the finish layer has completely dried, the surface is cleaned of dust and primed again. This will eliminate possible minor defects and prepare the drywall walls for wallpapering.