Terms of the Trade: What Is a Putty Knife?

A putty knife scraping grout on red tile.

A putty knife is most commonly used for applying putty or compound to the joints, seams, and flaws of walls. But it can actually be used for more applications, such as spreading plaster; scraping off paint, wallpaper, or glue; and as a substitute screwdriver using the edge of the blade. This wide, flexible blade and the short handle make it a useful tool to have at your disposal no matter what your diy skill level.