| 摘要 |
PROBLEM TO BE SOLVED: To enhance the fire resistance and to facilitate the assembly operation of stairs by forming stair component members from a plaster board having a high specific gravity. SOLUTION: Stairs are made of a gypsum board having a thickness which can offer a satisfactory fire resistance, with which metal pillars 5, metal ceiling beams 6 and metal floor beams 7 can be covered. A plurality of horizontally laid stair treads 17 and a plurality of vertically arranged risers 15 are provided so as to couple open string panels 13 therebetween which are arranged on opposite sides of the stairs, the stair treads 17 and the lower surface of the risers 15 are covered with a facing member 16, the open string panels 13, the stair boards 14, the risers 15 and the facing member 16 being made of a gypsum board having a high specific gravity. Accordingly, the fire resistance can be enhanced, and further, nailing can be made for joining the stair components together since they are made of the gypsum board having a high specific gravity, thereby it is possible to facilitate the assembly of the stairs 12. |
