Which term describes a wood preservative that penetrates timber fibres to protect against borers, wood lice and fungi?

• A. Cupping
• B. Density
• C. Creosote
• D. Design for assembly

Answer: (C)

The concept here is a preservative that actually soaks into the wood rather than just coating the surface. Creosote is a coal-tar–based preservative that penetrates into timber fibres, diffusing through the wood’s pores and cell walls. This penetrating action gives durable protection against wood‑boring insects and fungi, making it a common choice for outdoor or structural timber where decay and infestation are concerns. The other terms don’t describe a preservative: cupping refers to distortion from moisture movement, density is a measure of mass per volume, and design for assembly is a design approach about how parts fit together. Creosote’s penetrating, biocidal action is what makes it the best fit here, though its use is regulated in many places due to toxicity and environmental considerations.