Abstract: The roofing structure includes roof sheets forming an inverted V-shape, together with a plurality of inverted T-bars extending between and secured to the lower ends of the roof sheets. Turnbuckles are provided in each T-bar to provide a contracting force tending to pull the ends of the T-bars towards each other and thus counter the gravitational force component tending to spread the lower ends of the roof sheets. The T-bars serve an additional function in defining support areas for ceiling panels in the form of the horizontal cross portions of the inverted T-shapes.