(57) Method for the construction and anchorage of a building structure or the like, preferably a launched and floating building (11 or several building sections, to a foundation. On the construction site there is prepared a foundation whose crown or head portion is located below the draught of the floating building structure (1). The structure (1) is supported against the foundation by means of pillars or legs such that at least the substantial portion of the loads is transmitted by the pillars to the foundation. The foundation is surrounded with a sheet pile wall with an opening through which the building structure is floated in over the foundation, and the opening is closed once the structure has been moved in over the foundation. The building structure is supported against the foundation and the water inside the pile sheet wall is thereafter evacuated.