Getting to Know Wallpaper-Removal Techniques
New wallcovering can transform a room, going from boring to beautiful. But before you can determine the best approach to removing wallpaper, you need to know the type of wallcovering and the type of wall surface that's under the wallpaper.
Knowing what you're up against
In most cases, walls are either drywall (gypsum sandwiched between layers of paper) or plaster smoothed over lath (either strips of wood or metal mesh). You can usually tell what you have by the feel (plaster is harder, colder, and smoother than drywall) or by tapping on it (drywall sounds hollow, and plaster doesn't). When in doubt, remove an outlet cover to see the exposed edges.
Drywall is more vulnerable to water damage; you must avoid overwetting it. And use care when you're scraping because drywall gouges more easily than plaster.
What about the wallpaper? Be optimistic — assume that the paper is dry-strippable. Lift a corner of the paper from the wall with a putty knife. Grasp the paper with both hands and slowly attempt to peel it back at a very low angle. If it all peels off, you're home free.
If the wallpaper doesn't peel off, or if only the decorative surface layer peels off, you must saturate the wallpaper or the remaining backing with water and wallpaper remover solvent and then scrape it off.
Some papers, such as foils or those coated with a vinyl or acrylic finish, are not porous. If you're removing such wallpapers, you must scratch, perforate, or roughen the entire surface to permit the solution to penetrate below the nonporous surface to the adhesive. You can test for porosity by spraying a small area with hot water and wallpaper remover. If the paper is porous, you should see the paper absorb the water immediately. After the paper is wetted, you can scrape it off.
Now that you know what you're dealing with, you can choose an appropriate removal technique for the entire surface. Depending on your situation, choose one of three wallpaper-removal approaches: dry-stripping, wallpaper remover, or steam.
Choosing a removal technique
The technique you use for removing the old wallpaper depends on what kind of paper you're taking down and what kind of surface is underneath (see the previous section, "Knowing what you're up against"). The following sections outline the steps involved in the different approaches. (For a video explanation of wallpaper removal, check out How to Remove Old Wallpaper.)
If a wallpaper is dry-strippable, you just need to loosen each strip at the corners with a putty knife and slowly peel it back at a 10- to 15-degree angle.
Don't pull the wallpaper straight out or you may damage the underlying surface, especially if it's drywall.
After you remove all the paper, follow the adhesive removal procedures the next section describes. If only the top, decorative layer peels off, leaving a paper backing behind, it's a peelable paper. Dry-strip the entire top layer and then follow the steps in the next section to take off the backing and adhesive.
If you plan to repaper and the old backing is secure and in good condition, you may be able to hang the new wallcovering right on top of it. Discuss this option with your wallpaper dealer.
Soaking and scraping it off
To remove nonstrippable paper or any paper backing that remains after dry-stripping a peelable paper's decorative layer, turn first to warm water and wallpaper removal solvent. Soak the surface with a wallpaper remover solution. Although a spray bottle works, the most effective way to get the solution on the wall and not all over the floor is to use a paint roller. Then scrape the sodden paper off with a wide taping knife or a wallpaper scraper.
Don't wet a larger area than you can scrape off within about 15 minutes. You shouldn't let water soak into drywall for longer than that, or it may cause unnecessary damage. Usually, you can wet about a 3-foot-wide, floor-to-ceiling section at a time.
Scrape off the wet wallpaper and let it fall to the floor. The canvas drop cloth or towels that you put down absorbs most of the dripping solution and keeps your shoe soles a little cleaner.
If the wallpaper is nonporous, you must roughen or perforate the surface so that the remover solution can penetrate and dissolve the adhesive. To roughen the surface, use coarse sandpaper on either a pad sander or a hand-sanding block. You can also use a neat gizmo called a Paper Tiger or another perforating tool devised for use on wallpaper applied over drywall. Rounded edges on these tools help ensure that you don't cause damage that may require subsequent repair. Don't use the scraper after the wallpaper is wet, though; you may damage the drywall. (Check out How to Take Off Wallpaper from Drywall by Soaking and Scraping for the details.)
If you're successful in using the soak-and-scrape approach, you can finish up the job. If not, it's time to pull out the big gun: a wallpaper steamer.
Giving it a steam bath
You're talking major work if you must remove more than one layer of wall-paper or remove wallpaper that has been painted over. And if the wallpaper was not applied to a properly sealed surface, removing it without damaging the wall can be next to impossible. For these tough jobs, you may have to rent a wallpaper steamer (about $15 for a half-day) or buy a do-it-yourself model (about $50). A wallpaper steamer is a hotplate attached to a hose extending from a hot water reservoir that heats the water and directs steam to the hotplate.
Although you can use a steamer and wallpaper scraper with relative confidence on plaster walls, use caution on drywall, which is much more vulnerable to water damage and is more easily gouged.
Fill the steamer with water and let it heat up, and keep a baking pan handy to put the hotplate in when you're not using it. Starting at the top of the wall, hold the hotplate against the wall in one area until the wallpaper softens. Move the hotplate to an adjacent area as you scrape the softened wallpaper with a wallpaper razor scraper and let it fall onto the plastic as described in the preceding section. When you're through scraping one area, the steamer usually has softened the next area, depending on the porosity of the paper. (The process is explained in How to Take Off Wallpaper from Drywall with a Wallpaper Steamer.)
Both steam and the water that condenses from it can drip off the hotplate and burn you. To prevent hot water from dripping down your arm, stand on a stepstool when you're working above chest height. Wear rubber gloves and a long-sleeved shirt, too.