To save time, outdated wallpaper is only too happy to simply be pasted over. The workload is significantly less, but the result is all the worse. Apart from the fact that existing bumps such as overlapping seams or bubbles also appear on the new strips, there is a real risk that the freshly applied paste will loosen the old wallpaper from the wall - and thus also the new ones. In addition, a smooth pattern does not look really smooth if there are layers of wallpaper with textures or woodchip underneath. Either way, you'll be doing yourself and the wall a favor by removing the old wallpaper before installing new ones. How this works best is explained as follows.
If the old wallpaper is already coming off by itself, so that its edges or corners are sticking out, you would like to pull it off the wall in one go. Unfortunately, this is not possible because the paste still holds most of the strips in place. At the latest when you try to tear off the loose pieces, you will notice that the work is not done in a few simple steps. The right preparation, which is based on a sophisticated system that can be divided into three steps, is all the more important. These are as follows:
Step 1: Soak and perforate wallpaper
To loosen the paste, you need to soak the wallpaper. There are three different methods for uncoated paper wallpaper. Either you use warm water and add a little washing-up liquid to it, or you use a special wallpaper remover. A pressure sprayer is suitable for soaking the walls as evenly as possible - it treats the wallpaper across the board. As an alternative to the two tools mentioned, you can also use a special steam wallpaper remover that soaks the paper wallpaper with the help of steam. Completely without chemicals.
Coated wallpapers, which have a water-repellent function, cannot be soaked as easily as those made of paper. They must first be perforated so that the water can penetrate to the paste. A so-called spiked roller is best suited for this: It scratches the wallpaper at certain points so that moisture can penetrate through the material. The application is very easy and also protects the base coat, which should not be damaged for the new wallpaper. After perforating, you can apply the rinse water or the wallpaper remover with the pressure sprayer as usual.
Let the rinsing water soak in until the strips turn dark – before you start removing the wallpaper. If you use a wallpaper remover, you should stick to the prescribed exposure time on the packaging. If you get to work too soon, the strips will not come off cleanly, so you will have a lot of trouble scraping off the remains. Go to work calmly and patiently: slowly and carefully peel off the wallpaper and use one or more spatulas if a strip does not come off properly in some places on the wall. Alternatively, a wallpaper scraper can also be used.
Step 3: Touch up any imperfections
When you've removed all the wallpaper leftovers, the wall should be nice and smooth. If this is not the case, it makes sense to carry out a few minor repairs before changing the wallpaper - to eliminate any unevenness. Smaller hairline cracks, chipped plaster or holes in the walls can be repaired with putty. You can also apply a deep primer (e.g. for plaster, gypsum or concrete) before wallpapering, painting, plastering or filling. As a result, the lengths can be effortlessly peeled off the next time, this applies above all to woodchip wallpaper and paper wallpaper that has been coated several times.
One more tip at the end: You can usually dispose of the leftover wallpaper in the residual waste. However, if you have particularly large quantities, you can take them to a recycling center.
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