What is Drywall?

What is drywall? It refers to either a product used to cover interior walls or the method of hanging the product. In either case, drywall replaced traditional plastering in the mid-twentieth century. For hundreds of years, plaster had been used to cover interior walls. It was a labor intensive process. Narrow boards called lath were nailed to the framing studs. Then plaster was applied and pressed into the gaps between the laths. This allowed the plaster to adhere to the wall. The plaster was then built up in layers. It was not a process that was easy to master and it required a craftsman to look right. Then drywall came along.

Drywall, the product, is a panel of gypsum plaster that is encased by fiber matting or heavy papers. Panels are usually manufactured in 4-foot widths and various lengths. The gypsum plaster is mixed with liquid to create slurry. The slurry is then poured on to one side of the encasing material. Another sheet is applied to the top. The whole thing is dried and compressed. Once drying is done, the product is trimmed for length and width. It comes packaged in stacks on large pallets wrapped in plastic. The pallets can be brought directly to the work site or picked up individually at the home store.

Drywall, the process, covers the methods used for using the product to sheathe interior walls. The product is cut and nailed directly to the studs. Holes are created for outlets, wall switches, and light fixtures. Once the product is adhered to the wall, gaps are covered with reinforced tape. The tape and all of the nail heads are covered with joint compound in successive layers. The compound is allowed to dry, then sanded down to a smooth finish. This simplicity, when compared to plastering, makes installing drywall something a typical do-it-yourselfer can do themselves. Repairs and new construction alike is relatively easy to master.

Drywall comes in many types that are used in different applications. The regular panels come in thicknesses from ¼” to ¾”. Fire resistant varieties are available in different thicknesses. These panels are impregnated with various substances that improve fire resistance. For applications where moisture may be a problem, greenboard is used. Cement board is used for showers and sauna rooms. Some drywall contains damping polymers to reduce sound penetration. Other drywall varieties are mold resistant and paperless. With each year, new varieties become available.

— Professional Power Tool Guide