what grit sandpaper for walls

When sanding walls, the grit of sandpaper you should use depends on the state of the wall. As a general rule, you should start with a coarse or medium 80-grit sandpaper to get rid of any large ridges or uneven areas. Once all the large obstacles have been removed, you can change to a finer sandpaper such as 120- or 150-grit sandpaper to achieve a smooth finish that is smooth to the touch. If youre sanding drywall and you have holes in the walls or deep gouges, youre better off first filling them in and then sanding over them to get rid of excess joint compound. For previously painted water-based paint, sand with a fine-grit sandpaper. For oil-based paint, a medium-grit sandpaper (100- to 150-grit) should be used. It is important to wear a mask to avoid inhaling any dust, and to contain the dust by closing the door of the room where youre working.