Which substance is used to protect timber by penetrating the fibres against attack by borers and fungi?

• A. Cupping
• B. Density
• C. Creosote
• D. Craft production

Answer: (C)

Timber protection relies on substances that penetrate the fibres to reach and protect the interior where decay and insect attack begin. Creosote is a coal-tar–based preservative that soaks into the wood, filling the cell spaces so the protective chemicals are distributed throughout the fibre network. This deep penetration helps deter fungi and borers by releasing toxic compounds inside the timber, creating a long-lasting barrier rather than just a surface coating. It’s especially useful for exterior or ground-contact timber because the protection is embedded within the wood itself.

Cupping describes moisture-induced warping of timber, not a protective chemical. Density is a physical property of wood, indicating mass per volume, and craft production refers to making items by hand or with machines, not a chemical treatment.