PURPOSE: To obtain excellent construction work efficiency and secure spring water space between a foundation slab and a floor slab so as to preclude the possibility of generating a trouble such as the clogging of a drain pipe.

CONSTITUTION: After placing concrete 3 for a foundation slab 1 and the lower part of a footing beam 2, spring water disposal members 10 made of concrete or foam polystyrene and provided with spring water disposal spaces 8 at the lower faces are laid in rows. Foam polystyrene plates 11 are stacked thereon up to the lower face height of a floor slab 6. The foam polystyrene plates 11 are adopted as a permanent form, and concrete for the floor slab 6 and footing beam 2 is placed thereon.