How to choose
Compare plywood, MDF, OSB and plasterboard around structure, moisture, finish, weight and dust.
Quick answer
Start with whether the sheet is structural, exposed to moisture, visible, load-bearing or only a finish surface. Thickness alone does not make different sheet families interchangeable.
Scope: Product selection does not replace structural design, hazardous-material identification or competent installation.
Four options to compare
Best for: Projects where edge finish, machining and surface appearance matter.
Main trade-off: MDF machines cleanly but is heavy, creates fine dust and needs suitable moisture protection.
Must check: Grade, thickness, edge treatment, fixing method and dust control.
Best for: Projects needing layered strength and better screw holding than fibreboard.
Main trade-off: Plywood quality, face grade, voids and exposure class vary widely.
Must check: Structural/exposure declaration, ply construction and supported span.
Best for: Documented OSB or other board grades used within their rated exposure and structural scope.
Main trade-off: A utility surface may be unsuitable for visible finish or persistent wetting.
Must check: Exact board grade, support spacing, edge sealing and installation guidance.
Best for: Plasterboard or task-specific boards within a documented wall/ceiling system.
Main trade-off: Fire, moisture, acoustic and load performance belongs to the complete system, not the board name alone.
Must check: Board type, framing, fixings, jointing and any system certification.
Separate appearance, stiffness, screw holding, moisture exposure, fire/acoustic system requirements and weight. If the project needs a designed structural value, use a competent specification.
Machining fibreboard and timber sheets creates dust. Use source extraction and controls appropriate to the material and process, and do not disturb suspect older boards without checking them.
What this guide cannot check
Do not claim universal safety, guaranteed suitability, professional approval or permission to undertake protected work. Check current instructions, exact identifiers and local circumstances before acting.