Q: We've learned that the wallpaper throughout the home we just bought was not applied with sizing. A contractor we consulted said the paper won't come off without ruining the walls. He suggested we paint over the existing wallpaper. Is that a good idea? - Ruth

A: The advice of the Quality Paint Institute, a paint-education organization, regarding painting wallpaper could be summed up as: "Well, if you must..." QPI ordinarily advises against painting wallpaper because its inks and dyes can bleed through the paint. Before turning to paint, you should exhaust your options for removing that wallpaper. In many cases, you just need to soak the wallpaper with water or a stripping solution available at paint stores (apply it with a sprayer or sponge) then scrape the paper off. In tough cases, use a scoring tool (also available at paint stores) to make narrow tears in the paper, letting the water or solution get behind the wallpaper. Really tenacious wallpaper may not let go until you rent a steamer. Always be careful to avoid damaging the wall when scraping off wallpaper.

If you decide that you need to paint wallpaper, QPI advises a thorough test of the results before you start painting an entire room or house. Start by making sure the wallpaper is clean and well-attached, especially at the seams. Use white glue to secure any loose corners. Then perform a test run on a hidden section of wall (it should include a seam for a full test) to make sure you get the desired results. Apply an oil-based, stain-blocking primer. The next day, apply a second primer coat to half the test area. On the third day, apply a flat latex paint over the entire test area. QPI says a flat finish hides wallpaper unevenness better than an eggshell or satin finish.

After the paint dries, decide how it looks. Inspect the differences between the areas that had one and two coats of primer to see how this affects the results.