There are a handful of ways to get rid of stubborn wallpaper that won't strip away, including homemade and commercial removers.
You can make homemade remover with equal parts water and vinegar or 25 percent liquid laundry softener and 75 percent water. Before you begin, protect your floor by taping a plastic sheet to the baseboards.
Once you get started, tackle one wall at a time. Use a sponge to cover the entire wall with water and repeat twice. Next, apply several coats of the remover to a section measuring about 3 square feet with a sponge, paint roller or liquid sprayer. Wait about 15 minutes and then peel off wallpaper with a scraper. Use a sponge or sponge mop and warm water to remove any remaining residue. Wipe away pasty residue from the wall using warm water and a sponge. Once you've done that, remove the tape from the plastic sheet protecting the floor and fold the corners toward the middle so that wallpaper scraps gather in the center. Discard both the sheet and scraps.
While commercial and homemade removers are made from different ingredients, they work for the same reason. An acid or base in the remover works as a catalyst for a chemical reaction with the water called hydrolysis, which breaks down the adhesive glue.
Wallpaper adhesive is sensitive to both acids and bases, which is why it responds effectively to wallpaper removers that have either an acid or a base as an active ingredient. Both kinds of remover penetrate the wallpaper's top layer, reaching the backing to break down and dissolve the glue.
Hydrolysis occurs when either acidic or basic wallpaper remover interacts with adhesive glue. Here's how it happens: Water is introduced to the adhesive in the presence of an acid or base, which allows water to break some of the molecular bonds in the adhesive. Water is then incorporated into some of the molecules that make up the adhesive.
Think of wallpaper adhesive as a brick wall. It won't topple over if you push against it because mortar holds all the bricks together. Remover breaks down the brick wall (i.e., the glue) by dissolving the mortar in between the bricks. Nothing is holding all the molecules together anymore and the bricks fall apart. The wall is no longer a wall; instead, it's just a pile of bricks (or individual molecules).
Now, let's consider a homemade remover made of vinegar and water. Acetic acid in the vinegar allows hydrolysis to take place. The adhesive that once glued the wallpaper to the wall no longer exists.
Read on to learn more about commercial wallpaper removers.