PURPOSE: To enhance work efficiency and insulation properties by forming female type and male type connection parts respectively on the end of a roof on both sides and enabling a roof to be covered by way of an insulation material.

CONSTITUTION: A female type connection end 4, which is folded to the upper side in the shape of S, is installed to one end of an oblong roof 1, thereby forming a projected piece engagement groove 2 and an insulation material insert recessed groove 3 while a male type connection end 7, which comprises an engagement. projected piece 7 folded in the shape of C and an engagement part 6, is installed to the bottom side of the roof on the opposite side-end. Folded parts 12 and 13 are installed respectively to enhance the strength. Then, reaction wood 21 and an engagement part 22 are mounted to the end of eaves so that they may be engaged with an engagement part 5 of the male type connection end 7 by way of an insulation material 15. Then, a next stage male type connection end 7 is covered over the insulation material insertion recessed groove 3 of the female type connection end 4, thereby inserting the engagement projected piece 5 of the male type connection end 7 into the projected piece engagement groove 2 of the female type connection end 4 for engagement.