Plasterboard, also known as drywall or wallboard, is a ubiquitous building material composed of several layers that provide structure, fireproofing, and design versatility. Peeling back these layers reveals the clever engineering and chemistry within.

The Core: Plaster Power

At the heart of plasterboard is a dense layer of hardened gypsum plaster. Gypsum is a mineral that has an unusual quality - when roasted and mixed with water, it changes phase from a powder into a solid, plaster form in a process called rehydration. The setting of plaster can be precisely controlled to produce a strong crystalline matrix.

Gypsum deposits are abundant globally, mined and then crushed into a fine white powder. This powder mixes with water, starch, foam, and other minor ingredients to produce plaster slurry. Between two thick paper liners, the slurry is sandwiched and spread to precise widths and thickness along huge conveyor belt production lines before the plaster sets.

As the plaster cures, a robust yet porous structure emerges, encased safely between protective paper barriers. Plaster offers fire resistance too as the gypsum crystals capture moisture, delaying the spread of flames. The qualities of density, crystallization, porosity, and dehydration make gypsum plaster an ideal material at the core of plasterboard.

The Protective Layers: Paper Armor

Surrounding the set gypsum plaster is typically two sheets of thick, molded paper. The paper liners provide a smooth surface for decorating and contribute strength through fibers that are knitted with crystallizing plaster. The paper also barricades moisture and improves fire resistance.

Paper production utilizes wood pulp or recycled paper fibers plus fillers like clay and limestone. The fibers bond under heat and pressure, forming long floppy sheets. Special paper-making machines then imprint the paper with patterns that increase surface area. As plaster fills these voids, it creates a mechanical anchor, joining paper to core.

Additives like glass fibers may also integrate into the paper as reinforcement. Fire and moisture resistance treatments such as wax or silicon permeate the paper barrier. The customized paper layers bolster and protect the gypsum plaster within.
Between Core and Paper: The Bonding Zone

Adhesion between paper lining and gypsum core is vital to prevent delamination and maintain stiffness. Integrating fibers into paper helps grip plaster, but additional glues and modifiers enhance this attachment further.

Starch adhesive coats paper fibers, bonding firmly with crystals in the hardening plaster. Some manufacturers apply polyvinyl acetate glue to the paper liner rather than using fiber additives and starches within paper production itself. Any holes in paper layers get filled with plaster slurry during board forming too.

Edge treatment also boosts bonding strength. Tapering paper fibers along the plasterboard edges creates improved friction and grip. The industry continues innovating chemical and mechanical techniques to optimize adhesion of paper to plaster core.

The Facings: Surface Design Options

Plasterboard’s paper liners provide an ideal surface for decorative finishes. The neutral white color, smooth texture, and absorbency take paints and wall coverings well. Manufacturers boost plasterboard versatility and value by enhancing paper facings.

Common options include vinyl coatings with embedded glass fibers. These create more durable abrasion- and moisture-resistant surfaces. Foil or foam backings add insulation while allowing decoration over the top surface. Some plasterboards receive primer seals or even complete roller-applied paint coverage, ready for installation.

Decorative panels for walls and ceilings build on these facing treatments with textured patterns that mimic wood, brick, stone, or metals. Custom wall sculpts apply plaster over base boards too. Such surface enhancements expand plasterboard aesthetics and market share within construction and do-it-yourself channels, building upon the fundamental paper liner design.

Plasterboard Profile: Sheet Size Standards

While variations exist, common plasterboard dimensions help builders efficiently clad interior spaces. Lengths up to 16 feet allow fast coverage of high walls and ceilings with fewer seams. Width runs from 30 to 54 inches, sufficient to span wall studs or roofing members on framing spaced 16 to 24 inches apart.

At its thickest point, standard core plasterboard measures 1⁄2 or 5⁄8 inches. Tapered edges slim down to 1⁄4 inch, assisting an easier fit into wall joints and concealment of seams during decorating. Piecing together boards is thus fast and seamless.

Lighter weight boards offer core reduction and corresponding limits on building code fire ratings and structural spans. Specialty profiles in curved, double-thickness, or fire-rated designs tailor boards for custom finishes and extreme climates or regulations. Overall, though, standard sheets parallel conventional building frameworks.

Plasterboard Strength: Structural Testing

Surface appeal alone fails to support building integrity. Plasterboard must perform physically too. Testing methods assess strength, demonstrating how plasterboard withstand construction stresses plus years of building movement and maintenance.
Force resistance evaluates plasterboard’s structure under straight vertical hanging loads for ceilings and shear stresses parallel to the board’s face from wind or impact. Multiple stud attachment points typically disperse such forces.

Flexural assessments bend samples in the direction perpendicular to board orientation. Strength here determines spanning capacity between structural members. Concentrated weights also push downward on small surface areas to evaluate point load capacity. In both tests, samples may deflect but should not rupture or detach from framing.

Bonding pull-off tests check paper adhesion using vacuum suction cups tugging paper facing from plaster core. Fastener withdrawal assays attach screws or nails through boards then tug outward, regulating the quality of plaster crystallization around embedded fasteners.
By combining metrics on compression, tension, bending, and attachment capacities, test standards guide minimum plasterboard grades for levels of construction based on building codes or warranty requirements.

Plasterboard Performance: Workability and Fire Resistance

In addition to strength, plasterboard demonstrates performance in construction workability and fire resistance. Composition again tailors these practical properties.

The set plaster core stands up to impacts, gouges, and fastener installation then resets around screws or nails, unlike brittle materials that might crack or crumble. Tough paper layers resist ripping or tear-out around fasteners as well. The plasterboard builds in forgiveness against common handling damages.

Fire ratings rely on chemistry and composition too. The plaster core contains chemically bound water that evaporates during intense heating, momentarily cooling boards and slowing heat transfer. Meanwhile paper chairs provide a protective barrier layer. Combined with non-flammable glass fiber mesh reinforcements, tested assemblies deliver certified fire resistance.

Final Words

The next time you gaze at a plaster wall or ceiling, consider the technology layered inside. Precision chemistry transforms mineral ore, plant pulp, and synthetic binders into one of construction’s most ubiquitous materials. Advanced understanding of composition continues expanding plasterboard performance too. Builders stick by versatile wallboard thanks to the strength within its stratification.