Historical wood structures face a significant challenge in preserving architectural heritage while meeting modern safety and durability standards, i.e., higher structural rigidity, soundproofing, and better thermal performance and fire protection. Wood structural floors among these structures are particularly vulnerable due to age, wear, and load requirements. Traditional methods of strengthening, such as complete replacement or adding additional supports, often compromise the original aesthetics and structural integrity. This paper explores various aspects of applying adhesive-based timber-concrete composite structures as a sustainable and efficient solution for strengthening historical wood structural floors while preserving their architectural authenticity. A high moisture-tolerant adhesive is used to bond the timber floor beams to a thin layer of fresh concrete placed on the top. The structural behavior of such composite beams is studied using finite element models and non-destructive material tests. The results indicate that the adhesive-based interlayer connection provides increased stiffness and load-carrying capacity, which leads to efficient composite members that can be conveniently employed in historical preservation projects. By reducing the need for extensive demolition and reconstruction, this approach aligns with conservation and sustainable development principles.