It used to be that interior walls were finished with layers of wet plaster troweled onto wooden strips, or lathe, that were nailed to wall studs. But that changed almost a century ago when the gypsum panel that’s named Sheetrock. Because of its success, other manufacturers have long since gotten into the act.
Known generally as drywall, this material is sold in thin, paper colored sheets that awre typically 4ft wide by 8 or 10ft long. They come in various thicknesses, and it is easy to install with nails or screws; panel seams between pieces are layered with thin paper tape and covered with drywall compound.
1. Before taping perimiter seams, lay down a thin bed of compound along the seam using a 4in wide knife. Press paper tape onto the joint, then wipe away the excess material. When the tape is dry, apply a second coat of compound with a 6in knife.
2. When the coat is dried, sand it lightly with the fine grit sandpaper. Apply one or two more coats on top, using the 6in knife.
3. Joints that run parallel to the drywall sheet’s long axis should be coated to 12in wide; those that run perpendicular to the axis (on the ends of the sheets) need to be coated to twice that dimension because drywall is not tapered at the ends as it is on the edges, making it harder to hide those joints.
Cover them with a very wide seam that has an extremely shallow taper. On subsequent passes, eliminate ridges and other imperfections by reducing the compound on the knife to a small glob.