Method for producing a building ceiling device which forms a ceiling of a building at least to a large extent, particularly preferably completely, which comprises at least one insulation material element (10a, 28a) that is made at least partially of a synthetic rigid foam, the insulation material element (10a, 28a) being made at least to a large extent of a thermoset material and being free from a thermoplastic material like for example polystyrene, being flame-retardant in accordance with class B and/or class C of the standard EN 13501-1 and having a thermal conductivity of less than 0,030 W/mK, the building ceiling device further comprising at least one support element, which is at least partially made of a freely mouldable and curable construction material and which receives a weight force of the insulation material element (10a, 28a) at least to a large extent, wherein in at least one pre-assembly step a mould, in particular a casting mould, is produced at least partially from the insulation material element and at least one further insulation material element, and wherein in at least one connecting step the freely mouldable and curable construction material is introduced into the mould formed at least by the insulation material elements (10, 28a) and is connected to the support element at least by substance-to-substance bond by a curing of the construction material, the insulation material element comprising at least one cover layer, which is in the connecting step connected to the construction material at least by substance-to-substande bond, characterised in that the cover layer is applied on a side of the synthetic rigid foam that is turned toward the support element. which forms a ceiling of a building at least to a large extent, particularly preferably completely, which comprises at least one insulation material element (10a, 28a) that is made at least partially of a synthetic rigid foam, the insulation material element (10a, 28a) being made at least to a large extent of a thermoset material and being free from a thermoplastic material like for example polystyrene, being flame-retardant in accordance with class B and/or class C of the standard EN 13501-1 and having a thermal conductivity of less than 0,030 W/mK, the building ceiling device further comprising at least one support element, which is at least partially made of a freely mouldable and curable construction material and which receives a weight force of the insulation material element (10a, 28a) at least to a large extent, wherein in at least one pre-assembly step a mould, in particular a casting mould, is produced at least partially from the insulation material element and at least one further insulation material element, and wherein in at least one connecting step the freely mouldable and curable construction material is introduced into the mould formed at least by the insulation material elements (10, 28a) and is connected to the support element at least by substance-to-substance bond by a curing of the construction material, the insulation material element comprising at least one cover layer, which is in the connecting step connected to the construction material at least by substance-to-substande bond, characterised in that the cover layer is applied on a side of the synthetic rigid foam that is turned toward the support element.