noun
interior finish material; interior finishing material
Refers to materials used for interior finishing in construction, such as flooring, wall coverings, and ceiling materials.
この内装材は耐火性に優れています。
This interior finish material has excellent fire resistance.
新しいオフィスには環境に優しい内装材
We used eco-friendly interior finishing materials for the new office.
建材 is a broader term for building materials in general, including structural elements, whereas 内装材 is limited to interior finishing materials.
Compound of 内装 (interior finishing) + 材 (material).