Repairing a Peeling Seam
Seams normally peel because of poor initial application or because of an overlap. Overlaps are sometimes unavoidable, and (particularly with vinyl papers) they tend to peel easily if white glue was not used on the overlap during initial application. In either case, overlaps or peeling seams are easily repaired by using the following technique.
Sometimes when paper dries, the seams between sheets peel and look unsightly (Image 1).
Carefully use a utility knife to pry back the overlap just enough to apply adhesive beneath it (Image 2).
Apply a small amount of white glue, taking care not to get it on the front of the wallpaper (Image 3).
Apply gentle pressure with a seam roller to flatten the seam edges together (Image 4).
Wipe the seam clean with a wet sponge (Image 5).
Dry the seam with a cloth, working in one direction to smooth the seam (Image 6).