We investigate the application of organosilane-based coatings as functional materials for the protective structural layer of wooden artifacts. To evaluate the protective efficacy, advanced sensing and characterization techniques—including colorimetry for color change analysis and the sessile drop method for optical contact angle measurement—were employed to perceive and quantify surface property variations. Organosilanes, specifically methyltrimethoxysilane (MTMS), can form stable Si–O–C bonds with cellulose through hydrolysis and condensation, creating a durable hydrophobic network within the wood. In this research, we compare the developed coating with polyethylene glycol (PEG) 2000, PEG 4000, and a commercial protective agent. Experimental results, quantified through these sensing instruments, demonstrate that the developed coating achieves high hydrophobicity with contact angles ranging from 90° to 120°, significantly outperforming the PEG-based groups. Furthermore, colorimetric sensing analysis indicates minimal color variation, with a total color difference (ΔE*) as low as 0.68 for Taiwan red cypress, thereby preserving the visual integrity of the artifacts. The coating also exhibits the fastest drying time and superior stain and acid resistance. These findings suggest that integrating functional material development with sensing evaluation offers a scientifically sound and highly operable technique for the sustainable conservation of wooden cultural heritages.