PURPOSE: To prevent damages brought about by falling of welding sparks, and to prevent rainwater from flowing down to lower stories.

CONSTITUTION: A fireproof core material 6 is wrapped with an external cover material 7. An upper covering material 8 is attached to the upper side of the external cover material 7. An internal extending edge 8a of the upper covering material 8 is stuck to a steel plate 2 on a floor 1 while an external extending edge 8b of the upper covering material 8 is stuck to an external wall 4. The upper covering material 8 is made of a material that is resistive against water and welding sparks.