Plasterboard is a building panel made from a core of gypsum (a naturally occurring mineral) sandwiched between two sheets of heavy paper. It’s used to create interior walls and ceilings in homes and commercial buildings, and it’s one of the most common construction materials in the world. You’ll also hear it called drywall, wallboard, or gypsum board, depending on where you live.
What Plasterboard Is Made Of
The core ingredient is calcium sulfate hemihydrate, a powder produced by heating crushed gypsum rock in a kiln to drive off excess water, then grinding it to a fine consistency. During manufacturing, this powder is mixed with water and a range of additives to form a wet slurry. That slurry is poured between two continuous sheets of recycled paper, one forming the front face and one forming the back. As the slurry moves down a conveyor belt, the calcium sulfate recrystallizes and hardens back into solid gypsum, bonding chemically and mechanically to the paper liners. The board is then cut to length and passed through large dryers to remove remaining moisture.
The additives in the core aren’t just filler. Foaming agents create tiny air voids that reduce the board’s weight. Starch improves the bond between gypsum and paper. Accelerators and retarders control how quickly the slurry sets, giving manufacturers precise control over production speed. The result is a rigid, flat panel that’s surprisingly easy to cut and install.
Standard Sizes and Thicknesses
The most common sheet size is 2400 × 1200 mm (roughly 8 × 4 feet), which covers 2.88 square meters and suits standard wall and ceiling heights. Smaller sheets at 1800 × 900 mm work well for patch repairs and tight spaces, while longer sheets up to 3600 × 1200 mm are used in commercial settings or tall rooms where fewer joints mean a cleaner finish.
Thickness determines both strength and application:
- 9.5 mm: Weighs about 22 kg per standard sheet. Used for ceilings with closely spaced joists, curved walls, and boarding over existing surfaces.
- 12.5 mm: Weighs about 27 kg per standard sheet. The default choice for most walls and ceilings.
- 15 mm: Weighs about 35 kg per standard sheet. Used for fire-rated walls and party walls between properties.
- 19 mm: Weighs about 43 kg per standard sheet. Provides a 60-minute fire rating in a single layer.
Types of Plasterboard
Standard plasterboard handles most interior jobs, but specialized versions exist for specific conditions.
Fire-Rated Board
Gypsum is naturally fire-resistant because of the water locked inside its crystal structure. When heated, that water releases as steam through a process called calcination. A wall built with gypsum board won’t transmit heat above 100°C (212°F) until every bit of gypsum in the panel has fully calcined. In standardized fire tests, the furnace temperature can exceed 980°C (1,800°F), yet the unexposed side stays cool for a rated period. Fire-rated boards, sometimes labeled Type X or Type C, contain glass fibers that reinforce the core as it calcines, or minerals like vermiculite that expand when heated to offset shrinkage. Building regulations typically require walls, partitions, and ceilings to provide 30, 60, 90, or 120 minutes of fire resistance. By varying board type and the number of layers, any of those ratings can be achieved.
Moisture-Resistant Board
Designed for kitchens, bathrooms, and utility rooms, moisture-resistant plasterboard uses additives in the core and treated paper facings to reduce water absorption. It’s not waterproof, so it shouldn’t be used in direct contact with standing water, but it holds up well in humid environments where standard board would soften over time.
Acoustic Board
Acoustic plasterboard has a denser gypsum core than standard board. The basic principle is simple: the heavier and denser a barrier, the harder it is for airborne sound to pass through it. Testing standards for drywall systems aim to block sounds of around 80 decibels under laboratory conditions. Acoustic board is most effective when used as part of a complete soundproofing system with resilient channels or insulation in the cavity, rather than as a standalone solution.
Foil-Backed Board
This type has a metallised polyester film bonded to the back face, acting as a vapor barrier. It’s used in rooms with high humidity or in external walls where you want to prevent moisture from migrating into the wall cavity. The foil layer also provides a small amount of thermal reflectance.
How Plasterboard Is Installed
There are two main methods, and the right one depends on what’s behind the board.
For solid masonry walls (brick or block), the most common approach is “dot and dab.” Blobs of adhesive are applied to the wall in a grid pattern, and the plasterboard is pressed onto them and leveled. This is fast, avoids the need for a frame, and creates a small air gap between the board and the masonry.
For stud walls, which are lightweight timber or metal frames used to create room partitions, the board is screwed directly to the studs. Stud walls are especially common on upper floors because they’re much lighter than masonry, reducing the load on the structure below. A screw gun with a depth-setting clutch drives screws just below the paper surface without breaking through it. A T-square helps you mark and score straight cuts, and a utility knife is all you need to cut standard board: score through the paper on one side, snap the board along the line, then cut the paper on the back.
Finishing a Plasterboard Surface
Raw plasterboard has visible joints between sheets and screw heads dotting the surface. Two finishing methods address this.
Taping and jointing (also called “dry finishing”) involves pressing paper or mesh tape into the seams between boards, then covering the tape and screw heads with layers of joint compound. Each layer is allowed to dry, then sanded smooth. The process is repeated two or three times, with each coat feathered wider than the last to blend the joint invisibly into the surrounding board. When done well, it produces a surface ready for paint.
Skim coating takes a different approach. A thin layer of finishing plaster is applied over the entire surface of the board, not just the joints. This creates a completely seamless finish with a harder, more uniform surface. Skimming takes more skill and is messier, but many decorators prefer it because it hides minor imperfections and provides an excellent base for both paint and wallpaper.
Recycling and Disposal
Plasterboard is almost entirely recyclable. The gypsum core can be separated from the paper liners and reused in new board production or as a soil amendment in agriculture. The paper component is also recyclable. In the European Union, plasterboard recycling contributes to a target of 70% recovery of construction and demolition waste. Sending plasterboard to landfill is increasingly restricted in many countries because the paper lining can degrade and produce hydrogen sulfide gas under certain conditions. Best-case recycling scenarios, where no gypsum waste goes to landfill, show measurably lower greenhouse gas emissions across the product’s life cycle compared to disposal. If you’re doing a renovation, most waste transfer stations now accept plasterboard separately for recycling.