A research project, Wood and Wood-Hybrid Midrise Buildings, was undertaken to develop information to be used as the basis for alternative/acceptable solutions for mid-rise construction using wood structural elements. As part of this project, three materials were selected for investigation as encapsulation materials for combustible structural elements: Type X gypsum board (12.7 mm thick and 15.9 mm thick), cement board (12.7 mm thick), and gypsum-concrete (25 mm thick and 39 mm thick). This report documents the results of cone calorimeter tests conducted to investigate the performance of the three encapsulation materials.