| 摘要 |
PURPOSE:To lighten a ceiling material by forming a tongue and a groove for mutually connecting the ceiling materials at the end sections of the ceiling material and mounting non-combustible materials on the underside side of the ceiling material and the underside of the tongue. CONSTITUTION:A ceiling material 1 consisting of the two layer structure of a base material 2 and a rear material 3 is formed, and a tongue 5 and a groove 6 mutually connecting the ceiling materials 1 are shaped at both end sections of the ceiling material 1. A taped surface 8 upward inclined toward a front end is formed on the underside of the tongue 5, and a nail is driven from the tapered surface 8, thus preventing the projection of a nailhead from the underside 3a of the rear material 3. A calcium silicate board 50 is used as the rails of the base material 2 and the rear material 3, and the calcium silicate board 50 is employed as a surface 4 on the underside side of the ceiling material 1 and a surface 7 on the underside side of the tongue 5. Accordingly, weight per one ceiling material can be reduced. |
