Lightweight drywall sounds like an oxymoron. But USG says that its Sheetrock UltraLight Panels are up to 30 percent lighter than conventional 1/2-inch panels. The company credits the weight loss to a “colloidal-chemistry” formulation that makes the material not just lighter but stronger, and says that the product can be applied over 24-inch on-center ceiling joists with no chance of sagging. It comes in most standard sizes and costs about 10 percent more than traditional Sheetrock. USG Corp., 800/874-4968, usg.com.