Formerly when ordinary printed wall coverings were all that were readily available, it was common practice to paper over existing wallpaper, often to the point where four or five successive layers would accumulate. This is no longer considered acceptable (and will not work at all over today’s washable and vinyl wall coverings), and it is always best to strip all old coverings before hanging new ones. Even if the old material looks sound, hanging a newly pasted wall covering over it may cause it to lift from the wall, creating ugly bubbles that are impossible to disguise. This also applies to the backing paper that is left on the wall after dry-stripping a vinyl wall covering; there is no guarantee that it is perfectly bonded to the wall, and so hanging another wall covering over it could give very poor results.
Once the room is cleared and dustsheets (drop cloths) Ire spread over the floor and any remaining furniture, the next step is to identify what type of wall covering is to be removed. An ordinary printed paper will absorb water splashed on it immediately; other types will not. The printed plastic layer of a vinyl wall covering will peel off dry, but thesu6ce of a washable paper will not come off in the same way unless it is a duplex paper made in two layers. With paper-backed fabric wall coverings, it is often possible to peel the fabric away from its paper backing; try this before turning to more complicated methods of removal.
To strip printed wallpapers, wet the surface with a sponger or a garden spray gun. Wait for the water to penetrate, and repeat if necessary.
Using a stiff wallpaper scraper – not a filling (putty) knife – start scraping the old paper from the wall at a seam. If necessary, wet the surface again while you are working.
Turn off the power before stripping around switches and other fittings, then loosen the faceplate screws to strip the wallpaper behind the fitting.
After removing the bulk of the old wallpaper, go back over the wall surface and remove any remaining paper with a sponge or spray gun and a scraper.
For quicker results, use a steam stripper to remove washable papers. Press the steaming plate to the next area of the wall while stripping the area just steamed.
Strip vinyl wall coverings by lifting a corner to separate the vinyl layer from the paper backing. Strip it off by pulling it away from the wall surface.
Always soak and remove the plain backing paper left on the wall after stripping away the vinyl. It may well not be a sound lining for a new wall covering.