CEILING BASE MEMBER, CEILING STRUCTURE, BUILDING, AND CONSTRUCTION METHOD OF BUILDING

To provide a ceiling base member capable of improving workability for attaching an airtight member so as to straddle between ceiling joist receivers.SOLUTION: A ceiling base member for a building comprises: a ceiling joist receiver which extends in a first direction and to which a hanging member can be connected; and a base airtight member having a covering portion adhered to an upper surface of the ceiling joist receiver via an adhesive layer so as to cover the whole of the upper surface of the ceiling joist receiver and at least one extension portion extending from the covering portion in at least one of second directions perpendicular to the first direction and extending in the first direction along the covering portion.SELECTED DRAWING: Figure 2 【課題】野縁受け間に跨がるように気密部材を取り付けるための施工性を向上することが可能な天井下地用部材を提供する。【解決手段】建築物の天井下地用部材は、第１の方向に延びるとともに、吊り部材を接続可能な野縁受けと、前記野縁受けの上面の全体を覆うように接着層を介して前記野縁受けの上面に接着された被覆部と、前記被覆部から前記第１の方向と直交する第２の方向の少なくとも一方に延びるとともに前記被覆部に沿って前記第１の方向に延びる少なくとも１つの延出部と、を有する下地用気密部材と、を備えている。【選択図】図２