Preparation of the surface for wallpapering
After removing the old wallpaper, rinse the wall with hot water, to remove the remnants of glue and soak stubbornly sticking scraps of paper. Then fill in holes and cracks. If you peel off the wallpaper (as long as it was not easily peelable wallpaper) presented no difficulties, means, that the surface is dusty, flaky or moist. Scrape off any flaking paint, investigate and remove the causes of moisture. Pull the wall with a layer of oil primer paint, to provide a uniform surface for the wallpaper to be applied. If you want to wallpaper a well-painted wall.
wash it with soap and water. It would be good to apply a layer of sizing. You can buy ready-made sizing or prepare an aqueous solution of wallpaper glue.
For thin linings, such as foil, showing all the inequalities, thorough surface preparation is even more important than with traditional wallpaper. It is best to stick a layer of backing wallpaper, and then – if the foil is translucent – paint over with neutral emulsion.