Use a spirit level to mark the perpendicular line for the first strip. This will ensure that all subsequent strips are glued straight. Place the top of the first strip up to the ceiling with an overlap and align with the perpendicular line drawn. Use a foam roller to press out any bubbles and smooth out any wrinkles. For the other strips, glue them on, flatten the edges and use the foam roller to remove all bubbles and wrinkles.
In the area where the ceiling meets the wall, press the wallpaper overlap, smooth with a wallpaper scraper and cut carefully with a knife.
Apply the adhesive to the wall or to the papered substrate with a brush, paintbrush or roller. Switch off the electricity when gluing over sockets and switches, unscrew the cover when gluing the wallpaper, stick the wallpaper on and then cut out. When gluing window recesses, allow the wallpaper to overhang and then cut it off accurately.
Do not wallpaper behind the radiator body itself. Always choose a visually suitable line to finish the roll of wallpaper at the radiator. For the radiator, just adjust the wallpaper by 10-15 cm.
Cut a strip of wallpaper at the corners so that it overlaps the next wall by about 2 cm. Cut this overlap in several places. The rest of the strip or a new strip is now applied over this overlap. For wallpaper with a thick texture, wallpaper the corner with only a small overlap.
A general rule of thumb when applying wallpaper to the ceiling is to start gluing the wallpaper on the ceiling from the window towards the centre of the room. Using a spirit level, mark two points at a distance of 50 cm in one line from the parallel wall. This will ensure that the other strips are always level, even if the wall is not straight. Stick the first strip along the line, always leaving a slight overlap of the wallpaper strip at the start, run a foam roller over the strip to smooth out bubbles and unevenness. Use a plastic spatula to press the excess roll into a corner or wall and trim with a knife. Wallpapering the ceiling always goes better in two.