A metal holder for disposing a guide structure on a concrete foundation, the holder having a top part in the form of an open housing which serves for lateral retention of the guide structure and in which fastening means can engage, the housing being provided with anchoring parts at the underside, wherein the housing is provided with a metal baseplate disposed in a plastic mortar panel which adjoins all round the housing by a horizontal top surface and which adjoins a layer of plastic mortar on the underside, said layer of plastic mortar completely surrounding the anchoring parts of the housing.