A concrete anchor comprises a head-section (A), a shaft (B) defining a longitudinal axis (6) and a tip section (C). The anchor has essentially the cross-section of a thin-walled tube with a channel extending along its central axis. Shaft (B) exhibits an external thread with a thread height and a thread pitch construed to enable the anchor to selftap a thread in building insulation material. Such an anchor is being used to in prefabricated concrete elements to secure insulation materials to the concrete body. To achieve this a mould for a concrete element is being provided, a concrete layer is poured into it and at least one layer of insulation material placed on the concrete layer. Then at least one concrete anchor according to the invention is screwed or driven through the insulation material layer into the concrete layer while the concrete has not yet fully hardened.
