PURPOSE: To facilitate the attachment of damp-proof membrane by a method wherein a receiver fitment, having a receiving piece projecting upwardly on continuous footing, is provided and a sleeper is attached to the receiving piece while the damp-proof membrane is secured and attached by the receiving piece and the sleeper.

CONSTITUTION: The substantially Z-shape receiver fitment 4 is attached to the upper surface of a leg piece 24 of a L-shape foundation fitment 22 fixed to the continuous footing 3 by a mounting piece 11 and an anchor bolt 21, the upper horizontal part 57 of upright side plate 54 of a bag-like boby 6 accommodated in a spece 2 under a floor is set below the receiving piece 12 and is fixed by the receiving piece and the lower surface of the sleeper 5. According to this constitution, the bag-like body 6 of a damp-proof membrane may be attached easily without damaging it.