Drywall

Drywall, also called gypsum board or plasterboard, is a panel made primarily of gypsum plaster pressed between two sheets of thick paper, used to finish the interior walls and ceilings of most modern buildings. Drywall largely replaced traditional wet plaster wall construction over the course of the twentieth century because it installs much faster, requires less skilled labor, and avoids the lengthy drying time that wet plaster construction demands before a space is ready for painting and occupancy.

Composition and Manufacturing

Standard drywall panels are manufactured by sandwiching a core of gypsum, a naturally occurring mineral, calcium sulfate dihydrate, between two layers of specialized paper that provide surface strength and a smooth, paintable finish. Gypsum itself has a useful property for building materials: it contains chemically bound water within its crystal structure, which is released as steam when gypsum is heated significantly, giving standard drywall a degree of inherent fire resistance since the panel absorbs heat energy converting that bound water to steam before the material behind it reaches damaging temperatures. Specialized drywall variants modify this basic composition for specific performance needs, including moisture-resistant board for bathrooms and other damp areas, fire-rated board with additional glass fiber reinforcement for enhanced fire resistance ratings, and soundproofing board with denser core material or laminated layers to improve acoustic isolation between spaces.

Installation Process

Installing drywall involves screwing or nailing panels to the underlying wall or ceiling framing, whether wood or metal studs, with joints between adjacent panels, along with any screw or nail heads, then covered using paper or fiberglass mesh tape embedded in joint compound, a paste-like material that bonds the tape and fills surface irregularities. Multiple coats of joint compound are typically applied and sanded smooth between coats, since achieving an invisible, flat joint between panels requires building up and feathering out the compound gradually rather than attempting to fill the joint in a single thick application. The finished level of smoothness required varies by application, with rating systems used in some markets to specify finish quality levels ranging from a basic fire-taped finish adequate for utility spaces to a smooth, imperfection-free finish required for surfaces that will receive glossy paint or will be viewed under raking light that reveals even minor surface irregularities.

Fire-Rated Wall and Ceiling Assemblies

Beyond individual panel fire resistance, drywall is a key component of fire-rated wall and ceiling assemblies, tested and certified combinations of specific framing, drywall type, layer count, and fastening pattern that achieve a documented fire-resistance rating measured in hours. Building codes require specific fire-rated assemblies at locations such as walls separating individual dwelling units, stairwells, and corridors that serve as life-safety egress routes, and any penetration through a fire-rated assembly, such as an electrical outlet box, pipe, or duct, must be properly sealed or fire-stopped to maintain the assembly tested rating, since an unsealed penetration can allow fire and smoke to bypass the wall protection entirely regardless of how well the surrounding drywall itself performs.

Sustainability and Waste Considerations

Drywall generates a significant volume of construction waste, both from manufacturing offcuts and from demolition of existing buildings, prompting growing attention to drywall recycling programs that grind waste gypsum board for reuse as an ingredient in new drywall manufacturing or as a soil amendment in agriculture, since gypsum also has beneficial properties for certain soil conditions. Some manufacturers have also increased the proportion of recycled or synthetic gypsum, including gypsum captured as a byproduct of industrial flue gas desulfurization processes at power plants, reducing reliance on mined natural gypsum while simultaneously putting an industrial byproduct to productive use rather than treating it purely as waste requiring disposal.

Acoustic Performance Considerations

Beyond fire resistance, drywall assemblies significantly affect how well sound transmits between adjacent spaces, a performance measured using a sound transmission class rating that quantifies how much an assembly reduces airborne sound passing through it. Builders can improve acoustic performance within a standard stud wall through several techniques without necessarily changing the drywall itself, including adding resilient channels that decouple the drywall from the framing to reduce vibration transfer, increasing the number or thickness of drywall layers, and filling the wall cavity with sound-absorbing insulation. Multifamily housing codes in many jurisdictions set minimum sound transmission class requirements for walls and floors separating individual dwelling units, making acoustic drywall assembly design a standard part of apartment and condominium construction documentation rather than an optional upgrade.

Meeting these ratings typically requires coordinating drywall selection with insulation type and framing detail early in design, rather than treating acoustic performance as a problem to solve after construction is already underway.

Builders who plan acoustic assemblies alongside the rest of a project schedule generally avoid the costly rework that retrofitting sound control into an already-finished wall assembly tends to require.

Testing labs offer field verification of installed sound transmission class performance, giving owners and builders an added layer of confidence before a project reaches final inspection.

This verification step has become increasingly standard on multifamily and mixed-use projects where occupant comfort complaints related to noise can otherwise generate costly disputes after move-in.

Getting the assembly right the first time remains far more cost-effective than attempting acoustic corrections after walls and finishes are already in place.

Manufacturers continue to refine drywall core formulations, improving fire and moisture performance while keeping installation methods largely consistent with long-established trade practice.

Editorially reviewed by Specialty Digest Editorial TeamLast reviewed November 3, 2026Researched and drafted with AI assistanceReport an issue