You are ALWAYS better off removing the paper underneath. Somethimes you won’t notice a problem, but if the wallpaper underneath starts to peel, then you have a problem. You could have lumpy walls! If you have a moisture problem or if one develops, you can be sure that the old wallpaper will peel off. Remember, it may look good right away, but after a while it might become obvious that you cut corners. If you want it to look fantastic, do it right! Previous owners in my home used to paper over existing paper, and it doesn’t look professional or neat after a little while.
You are ALWAYS better off removing the paper underneath. Somethimes you won’t notice a problem, but if the wallpaper underneath starts to peel, then you have a problem. You could have lumpy walls! If you have a moisture problem or if one develops, you can be sure that the old wallpaper will peel off. Remember, it may look good right away, but after a while it might become obvious that you cut corners. If you want it to look fantastic, do it right! Previous owners in my home used to paper over existing paper, and it doesn’t look professional or neat after a little while.
You should always remove the existing paper before re papering.
This method is only as good as the glue on the original paper, I think the best thing is to remove the first layer.