of the membrane 18 is then adjusted keeping in mind that when attached and inflated it will become the converse of the configuration observed in the draped mode thus the height and configuration of the ceiling to be formed is predetermined by adjusting the drape of the membrane 18 to a contour complemental to the shape desired to be made prior to inflation of same as shown in fig5 the membrane 18 may be attached to the upper edge of the outer wall panel 15 by means of a strip 19 which is attached to the upper peripheral edge of the outer wall panel 15 with the membrane 18 captured therebetween alternatively the strip 19 may be placed on the interior panel 14 by placing the strip on the interior surface as shown in phantom in fig5 after all the portals such as windows and doors are closed and sealed an air blower is used to draw air from the outside of the structure to the inside of the structure thereby creating a slight high pressure area within the structure which forces the membrane 18 to inflate and rise upwardly to the configuration desired the strip 19 holds the membrane 18 in place and seals same along the entire upper periphery of the wall panels 14 and.