Surface prep determines how well coverings adhere, hence how good the job looks and how long it lasts. Ideally, surfaces should be clean, dry, flat, and stable. Before hanging wallcoverings, assess existing surfaces; remove, replace, or repair them as necessary; and then prime and seal them. Sealing surfaces improves adhesion and, just as important, allows you to remove coverings later without destroying the underlying drywall or plaster.
In the old days, a wall was sized, or brushed with a glutinous mixture to improve the adher
ence of the wallpaper. But sizing is rarely done today because it’s chemically incompatible with many pastes, causing them to crystallize, lump, and bubble, creating voids where the covering is unattached. Instead, professionals use one of the primer-sealers described in "Primer-Sealers for Wallcoverings,” below.
Before you start prep work, move furniture from the room or move it to the room’s center and cover it with a tarp. That will allow you to work faster and be safer. О Speaking of safety, always use a voltage tester to be sure electrical power is off where you’re working. Also set up ladders and scaffolds so they don’t wobble. Wear a respirator mask when applying chemicals, and clean up waste as you go.
