Which term refers to a warp across the width of the face of wood, with edges higher or lower than the centre?

• A. Density
• B. Creep
• C. Creosote
• D. Cupping

Answer: (D)

Cupping is a warp across the width of the wood’s face where the edges are higher or lower than the center. It happens when moisture content is uneven between the two faces, so one side dries or swells differently from the other. As the board loses or gains moisture unevenly, it curves across its width, creating a shape where the edges rise or fall relative to the middle. This specific distortion differs from other terms that describe different properties or behaviors: density is about mass per volume, creep is slow deformation under a sustained load, and creosote is a preservative chemical used to treat wood. To reduce cupping, balance moisture on both faces, store boards flat and properly supported, and acclimate them before use.