A device for installing drywall or other sheet materials on a ceiling where access to the joists is limited by an existing ceiling or vapor barrier. The device aligns with the leading edge of an installed sheet, braces against the floor, and provides a support ledge for the trailing edge of a new sheet as it is installed. A clearance gap in the device allows it to be removed while leaving a flush seam between the two sheets. The same device serves to support the leading edge of the new sheet as it is raised into position.