Construction of a ground-level, covered terrace directly attached to the house

Did you screw the lamp upstairs on with steel screws? It's already leaking rust juice. It should be fastened with stainless steel screws

We just bought the house and the lamps were attached like that. Everything will be properly fixed soon.

Without concrete, the gravel would basically be separated from the house facade only by stud foil - I just have the fear that over time (from below or above) moisture will somehow form on the house.

With concrete, moisture would be kept at the base.

Without concrete, the gravel would basically only be separated from the house facade by a stud foil - and I just fear that over time (from below or above) moisture will somehow form on the house

Why should moisture accumulate there? You certainly have a gravel cushion under the house as well as around the frost skirts. Water can drain away there. As long as your house is not built in a hollow, no water will come from below.

Moisture would be retained at the base with concrete.

Since we also want to place a pergola (on four posts) directly against the house and foundations are necessary here, these must also be concreted directly against the house (facade and base). Does there need to be insulation or something similar between the concrete and the house?

Before the final coat of paint, a mineral sealing slurry (e.g. baumit DS 26 Flex) is applied to the base, which permanently protects the base plaster (usually a cement-based plaster) from moisture. Only after the sealing slurry is applied, a fleece-laminated studded membrane (fleece facing the soil) is attached to the base and extended up to the ground level. In the base area, a silicone resin paint is recommended because it is highly hydrophobic and still vapor-permeable.