If you want to rework a wall, for example by applying decorative plaster or stucco to it, it is necessary to start with a good wall. This means that there must be no residues of other finishes on the wall, such as residues of wallpaper glue. When wallpapering, an adhesive is used that ensures that the wallpaper remains in place, but is also relatively easy to remove. However, the wallpaper glue itself does leave a lot of residue when removing wallpaper. To remove this is often quite a job.
Remove wallpaper
Removing wallpaper is often a relatively simple job. It is often enough to steam off the wallpaper with a suitable device. In many cases, the wallpaper simply comes off and it is often only the edges of the wallpaper that are more difficult to remove; in many cases because a plinth or something similar has been applied over the wallpaper. However, once the wallpaper has been removed using this method, there will always be a residue on the wall. This residue is wallpaper glue, which still feels a bit sticky after steaming. If nothing is done with it, the wallpaper glue dries up again by itself, but leaving the remains of wallpaper glue in place is not a good basis for further treatment of the wall, with the exception of re-wallpaper.
Risk of leaving wallpaper glue residue
The risk that arises from leaving old wallpaper glue in a new finish is that the glue will become visible through the new finish. For example, if it is painted over or another treatment is applied, spots with a lot of wallpaper glue residue often appear yellowish through the finish. It may also be the case that an overpainted wall starts to peel off in certain places. This occurs in places where there is still a lot of wallpaper glue. It is therefore important to remove all wallpaper glue before choosing a different finish. This is to avoid any additional work afterwards.
Finding remnants of old wallpaper glue
One of the easiest ways to discover the wallpaper glue is right after removing the old wallpaper. The removal of old wallpaper is often done by means of a steam device, whereby the wallpaper glue becomes moist. After removing the old wallpaper, it is often noticeable that there are spots on the wall that feel sticky; these are the places where there is still wallpaper glue on it. Even if the wallpaper was collected a little longer ago, wallpaper glue is still relatively easy to trace. If wallpaper glue gets wet, it will become tacky again. So wet an old wall, for example with a plant sprayer or sponge, and then wait a few minutes. If the surface is then tacky, there is wallpaper glue on it.
Remove wallpaper glue residues with water and a sponge
The easiest and least drastic way to remove the remains of wallpaper glue is to wet and keep the surface well and then remove the wallpaper glue with a sponge. The easiest way to do this is to thoroughly wet the entire wall once using a good wet sponge, for example, and then keep the surface wet every few minutes with a plant sprayer. Keep the wall wet for about an hour; this is necessary to ensure that the water penetrates well into the wallpaper glue and all cracks where wallpaper glue is still present. After about an hour we can assume that the water has penetrated well and the wall can be scrubbed off well with a sponge. This will wipe the wallpaper glue off the wall. Make sure that the water with wallpaper glue does not contaminate the floor covering or laminate, in both cases this can lead to annoying spots that are difficult to remove. Particularly with floor covering it is very difficult to remove such spots.
Check the wall for residue
After the wall has been thoroughly scrubbed, it must be checked whether the wallpaper glue has really gone away. This can be done by wetting the wall again and checking if the wall is still sticky. If this is not the case, the wallpaper glue has been removed properly. If the wall still feels tacky, the named method of removing the wallpaper glue can be repeated again. Sometimes it can take twice to remove the wallpaper glue properly.
Removal of wallpaper glue by sanding
If it is not possible to use the above method to remove the wallpaper glue, sandpaper can also be used. This method is a bit more drastic than wetting and wiping away the wallpaper glue, but there are situations in which this is still a good alternative. For example, if it concerns a relatively rough wall, in which some irregularities have to be sanded away anyway, it would only mean extra work to remove the wallpaper glue with water in advance. In such cases, the wallpaper glue can easily be sanded off with a somewhat coarser grit. If there is only light sanding, it is also necessary in this way to check afterwards whether the wallpaper glue is actually gone. In this case, too, you can do this by just wetting the wall and checking if there is still a sticky substance on the wall. If not, the wallpaper glue has been removed successfully.
If pick-up is not possible
If removing old wallpaper glue by sanding is also not possible, it is also possible to re-apply wallpaper over the wall. By using fiberglass wallpaper for this, it is still possible to choose a texture, or no texture, on the wall and then simply paint it over. When applying glass fiber wallpaper it is important that the wall in question does not have any irregularities, since such irregularities continue to shine through in the new wallpaper.
