BUILDING

PROBLEM TO BE SOLVED: To provide a building that is prevented from water leakage flowing in a gap between a bathroom unit and a building enclosure wall, even if the water leakage to the outside of the bathroom occurs from a joint portion between a fitting frame of a frame material and a sash frame caused by insufficient caulking and the damage of caulking due to aged deterioration.SOLUTION: A building is characterized by: installing a water stop member 5 formed of a sheet-like water-impermeable material so that a bottom face covering part 51 covers a bottom face 11a of a building frame opening part 11 and an external wall covering part 53 covers the lower part of the building frame opening part 11 of a building frame wall 1; fitting a building frame fitting part 32 of a sash frame 3 in the building frame opening part 11 so as to be received from the lower part to the bottom face covering part 51, and providing a water flashing weir 6 across the full width in the width direction of the building frame opening part 11 on the bottom face covering part 51; and providing a water leakage guiding structure for guiding so that the water leakage from a bathroom 2 flowing downward of the fitting frame 41 drops on the bottom face covering part 51 outside the building outside from the weir 6 through a joint portion between a fitting frame 41 and the building frame fitting part 32 from an imperfect portion of caulking 7.