Paper-based wallpaper expands during the soaking period, the strip becomes slightly wider and longer. If soaking times are different for various strips of wallpaper, it can lead to creases, open seams after drying, blistering and incorrect pattern alignment at the edges.
Creases after drying
If the soaking time is too short, the length of wallpaper continues to expand on the wall until it reaches its final length and width. When drying, unsightly creases appear due to the contraction. These are difficult or impossible to remove later.
Open seams after drying
If soaking times are too short and the room temperature is too high or there is a draught, open seams will appear after drying. If the wallpaper has not been able to expand completely and dries faster than the paste due to draughts or room temperatures above 18 degrees, the drying tension causes seams to burst.
Air bubbles
Air bubbles are another result of short soaking times, as the wallpaper continues to expand on the wall. This is due to the wood fibres in the paper. If the wallpaper dries too quickly as a result of high room temperatures or draughts, air is trapped which results in the formation of bubbles.
Incorrect pattern alignment at the edges
For patterned wallpaper, if individual strips of wallpaper have different soaking times, the edges will not align properly. These differences in expansion are tricky to deal with, making the wallpapering process considerably more difficult and/or longer because there might be no other solution than to start again.