Wallpaper has always been a quick, colorful way to give a room style and visual interest. Unfortunately, ripped seams, bubbles, tears and other damage are common. And if you don't fix these problems right away, you'll end up having to replace the entire piece of wallcovering.
The good news: Fixing wallpaper isn't especially difficult, though it does take a few specialized tools and techniques. We'll focus on the three most common wallpaper repairs: loose seams, punctures and trapped air bubbles.
To make repairs as invisible as possible, work slowly and carefully. Rushing yields sloppy work that's much harder to fix the second time around.
Vertical seams between strips of wallpaper become loose for a variety of reasons. Too much glue might have been squeezed out of the seam when it was rolled flat. Or, with prepasted vinyl wallcoverings, seams start to peel open because the factory-applied adhesive didn't stick to the vinyl.
What's more, seams on outside wall corners are prone to bumps and abrasions.
No matter where the loose seam is or what caused it, the repair procedure is the same: Dip a small artist's brush into wallpaper-seam adhesive (about $3 for a 4-ounce tube at paint and wallcovering stores).
Spread an even coat of adhesive onto the underside of the exposed seam. Then use a wooden seam roller to flatten the seam. Clean off any excess adhesive with a damp sponge.
If a loose seam has a small, horizontal tear, be sure to roll the two flaps of the tear back down in their original position. Place the top piece--the one with the decorative vinyl surface--over the bottom flap to effectively hide the ragged white line of the backing paper.
Rip and Puncture Repair
Severe rips and punctures mean you'll have to cut out the damaged area, fix the drywall if needed and install a wallpaper patch. You'll need a piece of matching wallpaper to use as the patch. If you don't have a remnant, buy a small sample at a wallcovering store.
If the pattern is no longer available, steal a piece from inside a closet or hallway.
A double-cut patch is the best way to make the repair nearly invisible. Start by taping the wallpaper patch over the damaged area with its pattern perfectly aligned with the one on the wall.
If the patterns don't line up precisely, don't panic; wallpaper tends to stretch a little once it's wet and rolled out. Simply align the patterns as close as possible.
With the patch taped in place, use a razor knife and straightedge to cut through both paper layers. Be sure to completely cut through each corner. Remove the patch and set it aside.
Next, carefully peel the damaged paper section off the wall. It probably will leave behind some felt backing; you can remove this sticky fuzz with a warm, damp sponge. Then patch any divots in the wall with a nonshrinking vinyl spackling compound .
If the wallpaper patch is prepasted paper, soak it in warm water for 30 seconds. Then "book" it by folding it over, paste to paste, to activate the adhesive. Let it set for about five minutes, then peel it apart and press the patch to the wall.
Use your fingertips to adjust the patch and align the pattern. Smooth the area with a damp sponge, then wipe off any excess paste. If the patch isn't prepasted or if you lifted it from another location, apply it to the wall with wallpaper paste.
Trapped air bubbles and blisters are almost always caused by an installation problem. Often, a speck of dirt or paint chip keeps the paper from bonding and allows a bubble to form with time and humidity. Or the installer didn't force out all of the air. Either way, the only cure is to cut open the blister, release the air and reglue the spot.
Most bubbles and blisters are just air pockets, but it pays to check. Press a finger against the bubble. Feel a speck of something? Cut an X through the paper and remove it with tweezers or a razor knife. Then, squeeze seam adhesive through the slit and roll the paper flat.
If the bubble really is just air, you can fix the problem with a glue-injecting syringe; it makes a less-conspicuous repair than cutting a slit. We bought ours, an Advance Equipment Co. model, at a Sherwin-Williams paint store for $5.50 (Buena Park,  522-0311; Costa Mesa,  241-8667; Huntington Beach,  847-2944; Los Alamitos,  490-3337; Santa Ana,  547-3366; or call  474-3794).
Reprinted from the pages of Today's Homeowner Magazine. To receive more expert advice on improving your home, call (800) 456-6369 or visit the Web site at http://www.todayshomeowner.com.